Book II. of the _Novum Organon Renovatum_. But each step in each of

ON THE

PHILOSOPHY

OF

DISCOVERY.

Cambridge:

PRINTED BY C. J. CLAY, M.A.

AT THE UNIVERSITY PRESS.

ON THE

PHILOSOPHY OF DISCOVERY,

CHAPTERS HISTORICAL AND CRITICAL;

BY

WILLIAM WHEWELL, D.D.

MASTER OF TRINITY COLLEGE, CAMBRIDGE, AND

CORRESPONDING MEMBER OF THE INSTITUTE OF FRANCE.

INCLUDING THE COMPLETION OF THE THIRD EDITION

OF THE PHILOSOPHY OF THE INDUCTIVE SCIENCES.

[Illustration: Hand passing torch to hand]

ΛΑΜΠΑΔΙΑ ΕΧΟΝΤΕΣ ΔΙΑΔΩΣΟΥΣΙΝ ΑΛΛΗΛΟΙΣ

LONDON:

JOHN W. PARKER AND SON, WEST STRAND.

1860.

The following are the latest editions of the series of works which has

been published connected with the present subject:

_History of the Inductive Sciences_, 3 Vols. 1857.

_History of Scientific Ideas_, 2 Vols. 1858.

_Novum Organon Renovatum_, 1 Vol. 1858.

_On the Philosophy of Discovery_, 1 Vol. 1860.

To the _History of the Inductive Sciences_ are appended two Indexes (in

Vol. 1.), an Index of Proper Names, and an Index of Technical Terms.

These Indexes, and the Tables of Contents of the other works, will

enable the reader to refer to any person or event included in this

series.

PREFACE

The two works which I entitled _The History of the Inductive Sciences_,

and _The Philosophy of the Inductive Sciences_, were intended to

present to the reader a view of the steps by which those portions of

human knowledge which are held to be most certain and stable have

been acquired, and of the philosophical principles which are involved

in those steps. Each of these steps was a scientific _Discovery_, in

which a _new_ conception was applied in order to bind together observed

facts. And though the conjunction of the observed facts was in each

case an example of logical _Induction_, it was not the inductive

process merely, but the _novelty_ of the result in each case which gave

its peculiar character to the History; and the Philosophy at which

I aimed was not the Philosophy of Induction, but the _Philosophy of

Discovery_. In the present edition I have described this as my object

in my Title.

A great part of the present volume consists of chapters which composed

the twelfth Book of the Philosophy in former editions, which Book was

then described as a 'Review of Opinions on the nature of Knowledge

and the Method of seeking it.' I have added to this part several new

chapters, on Plato, Aristotle, the Arabian Philosophers, Francis Bacon,

Mr. Mill, Mr. Mansel, the late Sir William Hamilton, and the German

philosophers Kant, Fichte, Schelling and Hegel. I might, if time had

allowed, have added a new chapter on Roger Bacon, founded on his _Opus

Minus_ and other works, recently published for the first time under the

direction of the Master of the Rolls; a valuable contribution to the

history of philosophy. But the review of this work would not materially

alter the estimate of Roger Bacon which I had derived from the _Opus

Majus_.

But besides these historical and critical surveys of the philosophy of

others, I have ventured to introduce some new views of my own; namely,

views which bear upon the philosophy of religion. I have done so under

the conviction that no philosophy of the universe can satisfy the minds

of thoughtful men which does not deal with such questions as inevitably

force themselves on our notice, respecting the Author and the Object

of the universe; and also under the conviction that every philosophy

of the universe which has any consistency must suggest answers, at

least conjectural, to such questions. No _Cosmos_ is complete from

which the question of Deity is excluded; and all Cosmology has a side

turned towards Theology. Though I am aware therefore how easy it is, on

this subject, to give offence and to incur obloquy, I have not thought

it right to abstain from following out my philosophical principles

to their results in this department of speculation. The results do

not differ materially from those at which many pious and thoughtful

speculators have arrived in previous ages of the world; though they

have here, as seems to me, something of novelty in their connection

with the philosophy of science. But this point I willingly leave to the

calm decision of competent judges.

I have added in an Appendix various Essays, previously published at

different times, which may serve perhaps to illustrate some points of

the history and philosophy of science.

TRINITY LODGE,

_February 8, 1856_.

ON

THE PHILOSOPHY OF DISCOVERY.

CONTENTS.

The chapters marked thus * appear now for the first time.

The chapters marked thus † have appeared in other works.

CHAP. I. INTRODUCTION.

CHAP. II. PLATO.

CHAP. III. * ADDITIONAL REMARKS ON PLATO.

1. The Doctrine of Ideas.

2. The Doctrine of the One and Many.

3. The notion of the nature and aim of Science.

4. The Survey of existing Sciences.

5. The Constitution of the human Mind.

CHAP. IV. ARISTOTLE.

CHAP. V. * ADDITIONAL REMARKS ON ARISTOTLE.

1. Induction.

2. Invention.

3. The One in the Many.

4. The "Five Words."

5. Aristotle's contribution to the Physical Sciences.

6. Aristotle's Astronomy.

7. Aristotle on Classification.

8. F. Bacon on Aristotle.

9. Discovery of Causes.

10. Plato and Aristotle.

11. Aristotle against Plato's _Ideas_.

CHAP. VI. THE LATER GREEKS.

CHAP. VII. THE ROMANS.

CHAP. VIII. * ARABIAN PHILOSOPHERS.

CHAP. IX. THE SCHOOLMEN OF THE MIDDLE AGES.

CHAP. X. THE INNOVATORS OF THE MIDDLE AGES.

Raymond Lully.

CHAP. XI. THE INNOVATORS OF THE MIDDLE AGES--_continued_.

Roger Bacon.

CHAP. XII. THE REVIVAL OF PLATONISM.

1. Causes of Delay in the Advance of Knowledge.

2. Causes of Progress.

3. Hermolaus Barbarus, &c.

4. Nicolaus Cusanus.

5. Manilius Ficinus.

6. Francis Patricius.

7. Picus, Agrippa, &c.

8. Paracelsus, Fludd, &c.

CHAP. XIII. THE THEORETICAL REFORMERS OF SCIENCE.

1. Bernardinus Telesius.

2. Thomas Campanella.

3. Andrew Cæsalpinus.

4. Giordano Bruno.

5. Peter Ramus.

6. The Reformers in General.

7. Melancthon.

CHAP. XIV. THE PRACTICAL REFORMERS OF SCIENCE.

1. Character of the Practical Reformers.

2. Leonardo da Vinci.

3. Copernicus.

4. Fabricius.

5. Maurolycus.

6. Benedetti.

7. Gilbert.

8. Galileo.

9. Kepler.

10. Tycho.

CHAP. XV. FRANCIS BACON.

1. (I.) General Remarks.

2. Common estimate of him.

3. We consider only Physical Science.

4. He is placed at the head of the change:

5. (II.) _He proclaims a New Era_;

6. (III.) _By a Change of Method_;

7. Including successive Steps;

8. Gradually ascending.

9. (IV.) _He contrasts the Old and the New Method._

10. (V.) _Has he neglected Ideas?_

11. No.

12. Examples of Ideas treated by him.

13. He has failed in applying his Method;

14. (VI.) _To the Cause of Heat._

15. He seeks Causes before Laws.

16. (VII.) _His Technical Form worthless._

17. He is confused by words.

18. His "Instances."

19. Contain some good Suggestions.

20. (VIII.) _His "Idols."_

21. (IX.) _His view of Utility._

22. (X.) _His Hopefulness._

23. (XI.) _His Piety._

CHAP. XVI. * ADDITIONAL REMARKS ON FRANCIS BACON.

1. Mr. Ellis's views.

2. Mr. Spedding's views.

CHAP. XVII. FROM BACON TO NEWTON.

1. Harvey.

2. Descartes.

3. Gassendi.

4. Actual Progress in Science.

5. Otto Guericke, &c.

6. Hooke.

7. Royal Society.

8. Bacon's _New Atalantis_.

9. Cowley.

10. Barrow.

CHAP. XVIII. NEWTON.

1. Animating effect of his Discoveries.

2. They confirm Bacon's views.

3. Newton shuns Hypotheses.

4. His views of Inductive Philosophy.

5. His "Rules of Philosophizing."

6. _The First Rule._

7. What is a "True Cause"?

8. _Such_ as are real?

9. Or _those_ which are proved?

10. Use of the Rule.

11. Rule otherwise expressed.

12. _The Second Rule._

13. What are Events "of the same kind"?

14. _The Third Rule_:

15. Not safe.

16. _The Fourth Rule._

17. Occult Qualities.

18. Ridiculed.

19. Distinction of Laws and Causes.

CHAP. XIX. LOCKE AND HIS FRENCH FOLLOWERS.

1. Cause of Locke's popularity.

2. Sensational School.

3. His inconsistencies.

4. Condillac, &c.

5. Importance of Language.

6. Ground of this.

7. The Encyclopedists.

8. Helvetius.

9. Value of Arts.

10. Tendency to Reaction.

CHAP. XX. THE REACTION AGAINST THE SENSATIONAL SCHOOL.

1. "Nisi intellectus ipse."

2. Price's "Review."

3. Stewart defends Price.

4. Archbishop Whately.

5. Laromiguière.

6. M. Cousin.

7. M. Ampère.

8. His Classification of Sciences.

9. Kant's Reform of Philosophy.

10. Its Effect in Germany.

CHAP. XXI. FURTHER ADVANCE OF THE SENSATIONAL SCHOOL.

M. Auguste Comte.

1. M. Comte on three States of Science.

2. M. Comte rejects the Search of Causes.

3. Causes in Physics.

4. Causes in other Sciences.

5. M. Comte's Practical Philosophy.

6. M. Comte on Hypotheses.

7. M. Comte's Classification of Sciences.

CHAP. XXII. † MR. MILL'S LOGIC.

(I.) What is Induction? §§ 1-14.

(II.) Induction or Description, §§ 15-23.

(III.) In Discovery a new Conception is introduced, §§ 24-37.

(IV.) Mr. Mill's Four Methods of Inquiry, §§ 38-40.

(V.) His Examples, §§ 41-48.

(VI.) Mr. Mill against Hypotheses, §§ 49, 50.

(VII.) Against prediction of Facts, §§ 51-53.

(VIII.) Newton's Vera Causa, §§ 54, 55.

(IX.) Successive Generalizations, §§ 56-62.

(X.) Mr. Mill's Hope from Deductions, §§ 63-67.

(XI.) Fundamental opposition of our Doctrines, §§ 68-71.

(XII.) Absurdities in Mr. Mill's Logic, §§ 72-74.

CHAP. XXIII. * POLITICAL ECONOMY AS AN INDUCTIVE SCIENCE.

1. Moral Sciences.

2. Political Economy.

3. Wages, Profits, and Rents.

4. Premature Generalizations.

5. Correction of these by Induction--Rent.

6. " Wages.

7. " Population.

CHAP. XXIV. † MODERN GERMAN PHILOSOPHY.

(I.) Science is the Idealization of Facts, §§ 1-8.

(II.) Successive German Philosophies.

Kant, Fichte, Schelling, Hegel, §§ 9-16.

CHAP. XXV. † THE FUNDAMENTAL ANTITHESIS AS IT EXISTS IN THE MORAL WORLD.

Moral Progress is the Realization of Ideas.

CHAP. XXVI. * OF THE "PHILOSOPHY OF THE INFINITE."

God is Eternal.

CHAP. XXVII. * SIR WILLIAM HAMILTON ON INERTIA AND WEIGHT.

1. Primary and Secondary Qualities.

2. Meaning of the Distinction.

3. Sir W. Hamilton adds "Secundo-Primary."

4. Inertia.

5. Sir W. Hamilton's arguments and reply.

6. Gravity.

Sir W. Hamilton's arguments and reply.

CHAP. XXVIII. † INFLUENCE OF GERMAN SYSTEMS OF PHILOSOPHY IN BRITAIN.

1. Stewart on Kant.

2. Mr. G. H. Lewes on Kant.

4-6. Mr. Mansel on Kant.

His objection to our Fundamental Ideas, and Reply.

7-10. New Axioms are possible.

11-13. Mr. Mansel's Kantianism.

14-16. Axioms are not from experience.

CHAP. XXIX. * NECESSARY TRUTH IS PROGRESSIVE.

Objections considered.

CHAP. XXX. * THE THEOLOGICAL BEARING OF THE PHILOSOPHY OF DISCOVERY.

1-4. How can necessary truths be actual?

5, 6. Small extent of necessary truth.

7. How did things come to be as they are?

8. View of the Theist.

9-12. Is this Platonism?

13. Idea of Time.

14, 15. Ideas of Force and Matter.

16. Creation of Matter.

17. Platonic Ideas.

18-21. Idea of Kind.

22. Idea of Substance.

23. Idea of Final Cause.

24, 25. Human immeasurably inferior to Divine.

26. Science advances towards the Divine Ideas.

27. Recapitulation.

CHAP. XXXI. * MAN'S KNOWLEDGE OF GOD.

1, 2. Opinions.

3. From Nature we learn something of God.

4-6. Though but little.

7, 8. From ourselves we learn something concerning God.

9-11. Objections answered.

12. Creation.

13. End of the World.

14. Moral and Theological views enter.

CHAP. XXXII. * ANALOGIES OF PHYSICAL AND RELIGIOUS PHILOSOPHY.

1, 2. Idealization of Facts and Realization of Ideas;

3, 4. Both imperfect.

5, 6. Divine Ideas perfect.

7-9. Realization of Divine Love.

10-13. Realization of Divine Justice.

14. Analogy of Physical and Moral Philosophy.

15, 16. Supernatural Beginning, Middle, and End indicated.

17. Suggestion of a Future State.

18-20. Confirmation from the Intellect of Man.

21. From the Moral Nature of Man.

APPENDIX.

PAGE

APPEND. A. OF THE PLATONIC THEORY OF IDEAS 403

B. ON PLATO'S SURVEY OF THE SCIENCES 417

BB. ON PLATO'S NOTION OF DIALECTIC 429

C. OF THE INTELLECTUAL POWERS ACCORDING

TO PLATO 440

D. CRITICISM OF ARISTOTLE'S ACCOUNT OF

INDUCTION 449

E. ON THE FUNDAMENTAL ANTITHESIS OF

PHILOSOPHY 462

F. REMARKS ON A REVIEW OF THE PHILOSOPHY

OF THE INDUCTIVE SCIENCES 482

G. ON THE TRANSFORMATION OF HYPOTHESES

IN THE HISTORY OF SCIENCE 492

H. ON HEGEL'S CRITICISM OF NEWTON'S

PRINCIPIA 504

Appendix to the Memoir on Hegel's Criticism

of Newton's Principia 513

K. DEMONSTRATION THAT ALL MATTER IS

HEAVY 522

ON THE

PHILOSOPHY

OF

DISCOVERY.

Wär' nicht das Auge sonnenhaft

Wie könnten wir das Licht erblicken?

Lebt' nicht in uns des Gottes eigne Kraft

Wie könnte uns das Göttliche entzücken?

GOETHE.

Were nothing sunlike in the Eye

How could we Light itself descry?

Were nothing godlike in the Mind

How could we God in Nature find?

CHAPTER I.

INTRODUCTION.

By the examination of the elements of human thought in which I have

been engaged, and by a consideration of the history of the most clear

and certain parts of our knowledge, I have been led to doctrines

respecting the progress of that exact and systematic knowledge which

we call Science; and these doctrines I have endeavoured to lay before

the reader in the History of the Sciences and of Scientific Ideas. The

questions on which I have thus ventured to pronounce have had a strong

interest for man from the earliest period of his intellectual progress,

and have been the subjects of lively discussion and bold speculation in

every age. I conceive that in the doctrines to which these researches

have conducted us, we have a far better hope that we possess a body of

permanent truths than the earlier essays on the same subjects could

furnish. For we have not taken our examples of knowledge at hazard,

as earlier speculators did, and were almost compelled to do; but have

drawn our materials from the vast store of unquestioned truths which

modern science offers to us: and we have formed our judgment concerning

the nature and progress of knowledge by considering what such science

is, and how it has reached its present condition. But though we have

thus pursued our speculations concerning knowledge with advantages

which earlier writers did not possess, it is still both interesting

and instructive for us to regard the opinions upon this subject which

have been delivered by the philosophers of past times. It is especially

interesting to see some of the truths which we have endeavoured to

expound, gradually dawning in men's minds, and assuming the clear

and permanent form in which we can now contemplate them. I shall

therefore, in the ensuing chapters, pass in review many of the opinions

of the writers of various ages concerning the mode by which man best

acquires the truest knowledge; and I shall endeavour, as we proceed,

to appreciate the real value of such judgments, and their place in the

progress of sound philosophy.

In this estimate of the opinions of others, I shall be guided by

those general doctrines which I have, as I trust, established in the

histories already published. And without attempting here to give any

summary of these doctrines, I may remark that there are two main

principles by which speculations on such subjects in all ages are

connected and related to each other; namely, the opposition of _Ideas_

and _Sensations_, and the distinction of _practical_ and _speculative_

knowledge. The opposition of Ideas and Sensations is exhibited to us

in the antithesis of Theory and Fact, which are necessarily considered

as distinct and of opposite natures, and yet necessarily identical,

and constituting Science by their identity. In like manner, although

practical knowledge is in substance identical with speculative, (for

all knowledge is speculation,) there is a distinction between the two

in their history, and in the subjects by which they are exemplified,

which distinction is quite essential in judging of the philosophical

views of the ancients. The alternatives of identity and diversity,

in these two antitheses,--the successive separation, opposition, and

reunion of principles which thus arise,--have produced, (as they may

easily be imagined capable of doing,) a long and varied series of

systems concerning the nature of knowledge; among which we shall have

to guide our course by the aid of the views already presented.

I am far from undertaking, or wishing, to review the whole series of

opinions which thus come under our notice; and I do not even attempt to

examine all the principal authors who have written on such subjects. I

merely wish to select some of the most considerable forms which, such

opinions have assumed, and to point out in some measure the progress

of truth from age to age. In doing this, I can only endeavour to seize

some of the most prominent features of each time and of each step, and

I must pass rapidly from classical antiquity to those which we have

called the dark ages, and from them to modern times. At each of these

periods the modifications of opinion, and the speculations with which

they were connected, formed a vast and tangled maze, the byways of

which our plan does not allow us to enter. We shall esteem ourselves

but too fortunate, if we can discover the single track by which ancient

led to modern philosophy.

I must also repeat that my survey of philosophical writers is here

confined to this one point,--their opinions on the nature of knowledge

and the method of science. I with some effort avoid entering upon other

parts of the philosophy of those authors of whom I speak; I knowingly

pass by those portions of their speculations which are in many cases

the most interesting and celebrated;--their opinions concerning the

human soul, the Divine Governor of the world, the foundations or

leading doctrines of politics, religion, and general philosophy. I

am desirous that my reader should bear this in mind, since he must

otherwise be offended with the scanty and partial view which I give in

this place of the philosophers whom I enumerate.

CHAPTER II.

PLATO.

There would be small advantage in beginning our examination earlier

than the period of the Socratic School at Athens; for although the

spirit of inquiry on such subjects had awakened in Greece at an earlier

period, and although the peculiar aptitude of the Grecian mind for

such researches had shown itself repeatedly in subtle distinctions

and acute reasonings, all the positive results of these early efforts

were contained in a more definite form in the reasonings of the

Platonic age. Before that time, the Greeks did not possess plain and

familiar examples of exact knowledge, such as the truths of Arithmetic,

Geometry, Astronomy and Optics became in the school of Plato; nor

were the antitheses of which we spoke above, so distinctly and fully

unfolded as we find them in Plato's works.

The question which hinges upon one of these antitheses, occupies

a prominent place in several of the Platonic dialogues; namely,

whether our knowledge be obtained by means of Sensation or of Ideas.

One of the doctrines which Plato most earnestly inculcated upon his

countrymen was, that we do not _know_ concerning sensible objects, but

concerning ideas. The first attempts of the Greeks at metaphysical

analysis had given rise to a school which maintained that material

objects are the only realities. In opposition to this, arose another

school, which taught that material objects have no permanent reality,

but are ever waxing and waning, constantly changing their substance.

"And hence," as Aristotle says[1], "arose the doctrine of ideas which

the Platonists held. For they assented to the opinion of Heraclitus,

that all sensible objects are in a constant state of flux. So that if

there is to be any knowledge and science, it must be concerning some

permanent natures, different from the sensible natures of objects;

for there can be no permanent science respecting that which is

perpetually changing. It happened that Socrates turned his speculations

to the moral virtues, and was the first philosopher who endeavoured

to give universal definitions of such matters. He wished to reason

systematically, and therefore he tried to establish definitions, for

definitions are the basis of systematic reasoning. There are two things

which may justly be looked upon as steps in philosophy due to Socrates;

inductive reasonings, and universal definitions;--both of them steps

which belong to the foundations of science. Socrates, however, did not

make universals, or definitions separable from the objects; but his

followers separated them, and these essences they termed _Ideas_." And

the same account is given by other writers[2]. "Some existences are

sensible, some intelligible: and according to Plato, if we wish to

understand the principles of things, we must first separate the _ideas_

from the _things_, such as the ideas of Similarity, Unity, Number,

Magnitude, Position, Motion: second, that we must assume an absolute

Fair, Good, Just, and the like: third, that we must consider the ideas

of relation, as Knowledge, Power: recollecting that the Things which

we perceive have this or that appellation applied to them because

they partake of this or that Idea; those things being _just_ which

participate in the idea of The Just, those being _beautiful_, which

contain the idea of The Beautiful." And many of the arguments by which

this doctrine was maintained are to be found in the Platonic dialogues.

Thus the opinion that true knowledge consists in sensation, which had

been asserted by Protagoras and others, is refuted in the _Theætetus_:

and, we may add, so victoriously refuted, that the arguments there

put forth have ever since exercised a strong influence upon the

speculative world. It may be remarked that in the minds of Plato and

of those who have since pursued the same paths of speculation, the

interest of such discussions as those we are now referring to, was by

no means limited to their bearing upon mere theory; but was closely

connected with those great questions of morals which have always a

practical import. Those who asserted that the only foundation of

knowledge was sensation, asserted also that the only foundation of

virtue was the desire of pleasure. And in Plato, the metaphysical

part of the disquisitions concerning knowledge in general, though

independent in its principles, always seems to be subordinate in its

purpose to the questions concerning the knowledge of our duty.

Since Plato thus looked upon the Ideas which were involved in each

department of knowledge as forming its only essential part, it was

natural that he should look upon the study of Ideas as the true mode

of pursuing knowledge. This he himself describes in the _Philebus_[3].

"The best way of arriving at truth is not very difficult to point out,

but most hard to pursue. All the arts which have ever been discovered,

were revealed in this manner. It is a gift of the gods to man, which,

as I conceive, they sent down by some Prometheus, as by Prometheus

they gave us the light of fire; and the ancients, more clear-sighted

than we, and less removed from the gods, handed down this traditionary

doctrine: that whatever is said to be, comes of One and of Many, and

comprehends in itself the Finite and the Infinite in coalition

(being One Kind, and consisting of Infinite Individuals). And this

being the state of things, we must, in each case, endeavour to seize

the One Idea (the idea of the Kind) as the chief point; for we shall

find that it is there. And when we have seized this one thing, we may

then consider how it comprehends in itself two, or three, or any other

number; and, again, examine each of these ramifications separately;

till at last we perceive, not only that One is at the same time One

and Many, but also _how many_. And when we have thus filled up the

interval between the Infinite and the One, we may consider that we

have done with each one. The gods then, as I have said, taught us by

tradition thus to contemplate, and to learn, and to teach one another.

But the philosophers of the present day seize upon the One, at hazard,

too soon or too late, and then immediately snatch at the Infinite; but

the intermediate steps escape them, in which resides the distinction

between a truly logical and a mere disputatious discussion."

It would seem that what the author here describes as the most perfect

form of exposition, is that which refers each object to its place in

a classification containing a complete series of subordinations, and

which gives a definition of each class. We have repeatedly remarked

that, in sciences of classification, each new definition which gives a

tenable and distinct separation of classes is an important advance in

our knowledge; but that such definitions are rather the last than the

first step in each advance. In the progress of real knowledge, these

definitions are always the results of a laborious study of individual

cases, and are never arrived at by a pure effort of thought, which is

what Plato appears to have imagined as the true mode of philosophizing.

And still less do the advances of other sciences consist in seizing

at once upon the highest generality, and filling in afterwards all

the intermediate steps between that and the special instances. On the

contrary, as we have seen, the ascents from particular to general are

all successive; and each step of this ascent requires time, and labour,

and a patient examination of actual facts and objects.

It would, of course, be absurd to blame Plato for having inadequate

views of the nature of progressive knowledge, at the time when

knowledge could hardly be said to have begun its progress. But we

already find in his speculations, as appears in the passages just

quoted from his writings, several points brought into view which will

require our continued attention as we proceed. In overlooking the

necessity of a gradual and successive advance from the less general to

the more general truths, Plato shared in a dimness of vision[4] which

prevailed among philosophers to the time of Francis Bacon. In thinking

too slightly of the study of actual nature, he manifested a bias from

which the human intellect freed itself in the vigorous struggles which

terminated the dark ages. In pointing out that all knowledge implies

a unity of what we observe as manifold, which unity is given by the

mind, Plato taught a lesson which has of late been too obscurely

acknowledged, the recoil by which men repaired their long neglect of

facts having carried them for a while so far as to think that facts

were the whole of our knowledge. And in analysing this principle of

Unity, by which we thus connect sensible things, into various Ideas,

such as Number, Magnitude, Position, Motion, he made a highly important

step, which it has been the business of philosophers in succeeding

times to complete and to follow out.

But the efficacy of Plato's speculations in their bearing upon physical

science, and upon theory in general, was much weakened by the confusion

of practical with theoretical knowledge, which arose from the ethical

propensities of the Socratic school. In the Platonic Dialogues, Art and

Science are constantly spoken of indiscriminately. The skill possessed

by the Painter, the Architect, the Shoemaker, is considered as a just

example of human science, no less than the knowledge which the geometer

or the astronomer possesses of the theoretical truths with which he

is conversant. Not only so; but traditionary and mythological tales,

mystical imaginations and fantastical etymologies, are mixed up, as

no less choice ingredients, with the most acute logical analyses, and

the most exact conduct of metaphysical controversies. There is no

distinction made between the knowledge possessed by the theoretical

psychologist and the physician, the philosophical teacher of morals

and the legislator or the administrator of law. This, indeed, is the

less to be wondered at, since even in our own time the same confusion

is very commonly made by persons not otherwise ignorant or uncultured.

On the other hand, we may remark finally, that Plato's admiration of

Ideas was not a barren imagination, even so far as regarded physical

science. For, as we have seen[5], he had a very important share in

the introduction of the theory of epicycles, having been the first to

propose to astronomers in a distinct form, the problem of which that

theory was the solution; namely, "to explain the celestial phenomena

by the combination of equable circular motions." This demand of an

ideal hypothesis which should exactly express the phenomena (as well

as they could then be observed), and from which, by the interposition

of suitable steps, all special cases might be deduced, falls in well

with those views respecting the proper mode of seeking knowledge

which we have quoted from the _Philebus_. And the Idea which could

thus represent and replace all the particular Facts, being not only

sought but found, we may readily suppose that the philosopher was, by

this event, strongly confirmed in his persuasion that such an Idea

was indeed what the inquirer ought to seek. In this conviction all

his genuine followers up to modern times have participated; and thus,

though they have avoided the error of those who hold that facts alone

are valuable as the elements of our knowledge, they have frequently run

into the opposite error of too much despising and neglecting facts, and

of thinking that the business of the inquirer after truth was only a

profound and constant contemplation of the conceptions of his own mind.

But of this hereafter.

FOOTNOTES:

[Footnote 1: _Metaph._ xii. 4.]

[Footnote 2: Diog. Laert. _Vit. Plat._]

[Footnote 3: T. ii. p. 16, c, d. ed. Bekker, t. v. p. 437.]

[Footnote 4: See the remarks on this phrase in the next chapter.]

[Footnote 5: _Hist. Ind. Sc._ b. iii. c. ii.]

CHAPTER III.

ADDITIONAL REMARKS ON PLATO.

The leading points in Plato's writings which bear upon the philosophy

of discovery are these:

1. The Doctrine of Ideas.

2. The Doctrine of the One and the Many.

3. The notion of the nature and aim of Science.

4. The survey of existing Sciences.

1. The Doctrine of Ideas is an attempt to solve a problem which in all

ages forces itself upon the notice of thoughtful men; namely, How can

certain and permanent knowledge be possible for man, since all his

knowledge must be derived from transient and fluctuating sensations?

And the answer given by this doctrine is, that certain and permanent

knowledge is _not_ derived from _Sensations_, but from _Ideas_. There

are in the mind certain elements of knowledge which are not derived

from sensation, and are only imperfectly exemplified in sensible

objects; and when we reason concerning sensible things so as to obtain

real knowledge, we do so by considering such things as partaking of

the qualities of the Ideas concerning which there can be truth. The

sciences of Geometry and Arithmetic show that there _are_ truths which

man can know; and the Doctrine of Ideas explains how this is possible.

So far the Doctrine of Ideas answers its primary purpose, and is a

reply (by no means the least intelligible and satisfactory reply) to

a question still agitated among philosophers: What is the ground of

geometrical (and other necessary) truth?

But Plato seems, in many of his writings, to extend this doctrine much

further; and to assume, not only Ideas of Space and its properties,

from which geometrical truths are derived; but of Relations, as the

Relations of Like and Unlike, Greater and Less; and of mere material

objects, as Tables and Chairs. Now to assume Ideas of such things as

these solves no difficulty and is supported by no argument. In this

respect the Ideal theory is of no value in Science.

It is curious that we have a very acute refutation of the Ideal theory

in this sense, not only in Aristotle, the open opponent of Plato on

this subject, but in the Platonic writings themselves: namely, in the

Dialogue entitled _Parmenides_; which, on this and on other accounts, I

consider to be the work not of Plato, but of an opponent of Plato[6].

2. I have spoken, in the preceding chapter, of Plato's doctrine that

truth is to be obtained by discerning the One in the Many. This

expression is used, it would seem, in a somewhat large and fluctuating

way, to mean several things; as for instance, finding the one _kind_ in

many _individuals_ (for instance, the one idea of dog in many dogs);

or the one _law_ in many _phenomena_ (for instance, the eccentrics and

epicycles in many planets). In any interpretation, it is too loose and

indefinite a rule to be of much value in the formation of sciences,

though it has been recently again propounded as important in modern

times.

3. I have said, in the preceding chapter, that Plato, though he saw

that scientific truths of great generality might be obtained and

were to be arrived at by philosophers, overlooked the necessity of a

_gradual_ and _successive_ advance from the less general to the more

general; and I have described this as a 'dimness of vision.' I must now

acknowledge that this is not a very appropriate phrase; for not only

no acuteness of vision could have enabled Plato to see that gradual

generalization in science of which, as yet, no example had appeared;

but it was very fortunate for the progress of truth, at that time, that

Plato had imagined to himself the object of science to be general

and sublime truths which prove themselves to be true by the light of

their own generality and symmetry. It is worth while to illustrate this

notice of Plato by some references to his writings.

In the Sixth Book of the _Republic_, Plato treats of the then existing

sciences as the instruments of a philosophical education. Among the

most conspicuous of these is astronomy. He there ridicules the notion

that astronomy is a sublime science because it makes men look _upward_.

He asserts that the really sublime science is that which makes men look

at the _realities_, which are suggested by the appearances seen in the

heavens: namely, the spheres which revolve and carry the luminaries

in their revolutions. Now it was no doubt the determined search for

such "realities" as these which gave birth to the Greek _Astronomy_,

that first and critical step in the progress of science. Plato, by his

exhortations, if not by his suggestions, contributed effectually, as

I conceive, to this step in science. In the same manner he requires

a science of _Harmonics_ which shall be free from the defects and

inaccuracies which occur in actual instruments. This belief that the

universe was full of mathematical relations, and that these were the

true objects of scientific research, gave a vigour, largeness of mind,

and confidence to the Greek speculators which no more cautious view of

the problem of scientific discovery could have supplied. It was well

that this advanced guard in the army of discoverers was filled with

indomitable courage, boundless hopes, and creative minds.

But we must not forget that this disposition to what Bacon calls

_anticipation_ was full of danger as well as of hope. It led Plato

into error, as it led Kepler afterwards, and many others in all ages

of scientific activity. It led Plato into error, for instance, when it

led him to assert (in the _Timæus_) that the four elements, Earth, Air,

Fire and Water, have, for the forms of their particles respectively,

the Cube, the Icosahedron, the Pyramid, and the Octahedron; and again,

when it led him to despise the practical controversies of the musicians

of his time; which controversies were, in fact, the proof of the

truth of the mathematical theory of Harmonics. And in like manner it

led Kepler into error when it led him to believe that he had found the

reason of the number, size and motion of the planetary orbits in the

application of the five regular solids to the frame of the universe[7].

How far the caution in forming hypotheses which Bacon's writings urge

upon us is more severe than suits the present prospects of science,

we may hereafter consider; but it is plainly very conceivable that

a boldness in the invention and application of hypotheses which was

propitious to science in its infancy, may be one of the greatest

dangers of its more mature period: and further, that the happy effect

of such a temper depended entirely upon the candour, skill and labour

with which the hypotheses were compared with the observed phenomena.

4. Plato has given a survey of the sciences of his time as Francis

Bacon has of _his_. Indeed Plato has given two such surveys: one,

in the _Republic_, in reviewing, as I have said, the elements of a

philosophical education; the other in the _Timæus_, as the portions

of a theological view of the universe--such as has been called a

_Theodicæa_, a justification of God. In the former passage of Plato,

the sciences enumerated are Arithmetic, Plane Geometry, Solid Geometry,

Astronomy and Harmonics[8]. In the _Timæus_ we have a further notice

of many other subjects, in a way which is intended, I conceive, to

include such knowledge as Plato had then arrived at on the various

parts of the universe. The subjects there referred to are, as I have

elsewhere stated[9], these: light and heat, water, ice, gold, gems,

rust and other natural objects:--odours, taste, hearing, lights,

colour, and the powers of sense in general:--the parts and organs of

the body, as the bones, the marrow, the brain, flesh, muscles, tendons,

ligaments and nerves; the skin, the hair, the nails; the veins and

arteries; respiration; generation; and in short, every obvious point

of physiology. But the opinions thus delivered in the _Timæus_ on the

latter subject have little to do with the progress of real knowledge.

The doctrines, on the other hand, which depend upon geometrical and

arithmetical relations are portions or preludes of the sciences which

the fulness of time brought forth.

5. I may, as further bearing upon the Platonic notion of science,

notice Plato's view of the constitution of the human mind. According

to him the Ideas which are the constituents of science form an

Intelligible World, while the visible and tangible things which we

perceive by our senses form the Visible World. In the visible world we

have shadows and reflections of actual objects, and by these shadows

and reflections we may judge of the objects, even when we cannot do

so directly; as when men in a dark cavern judge of external objects

by the shadows which they cast into the cavern. In like manner in the

Intelligible World there are conceptions which are the usual objects of

human thought, and about which we reason; but these are only shadows

and reflections of the Ideas which are the real sources of truth.

And the Reasoning Faculty, the Discursive Reason, the _Logos_, which

thus deals with conceptions, is subordinate to the Intuitive Faculty,

the Intuitive Reason, the _Nous_, which apprehends Ideas[10]. This

recognition of a Faculty in man which contemplates the foundations--the

_Fundamental Ideas_--of science, and by apprehending such Ideas, makes

science possible, is consentaneous to the philosophy which I have

all along presented, as the view taught us by a careful study of the

history and nature of science. That new Fundamental Ideas are unfolded,

and the Intuitive Faculty developed and enlarged by the progress of

science and by an intimate acquaintance with its reasonings, Plato

appears to have discerned in some measure, though dimly. And this is

the less wonderful, inasmuch as this gradual and successive extension

of the field of Intuitive Truth, in proportion as we become familiar

with a larger amount of derived truth, is even now accepted by few,

though proved by the reasonings of the greatest scientific discoverers

in every age.

The leading defect in Plato's view of the nature of real science is his

not seeing fully the extent to which experience and observation are the

basis of all our knowledge of the universe. He considers the luminaries

which appear in the heavens to be not the true objects of astronomy,

but only some imperfect adumbration of them;--mere diagrams which may

assist us in the study of a higher truth, as beautiful diagrams might

illustrate the truths of geometry, but would not prove them. This

notion of an astronomy which is an astronomy of Theories and not of

Facts, is not tenable, for Theories _are_ Facts. Theories and Facts

are equally _real_; true Theories are Facts, and Facts are familiar

Theories. But when Plato says that astronomy is a series of problems

suggested by visible things, he uses expressions quite conformable

to the true philosophy of science; and the like is true of all other

sciences.

FOOTNOTES:

[Footnote 6: This matter is further discussed in the Appendix, Essay A.]

[Footnote 7: These matters are further discussed in the Appendix, Essay

B.]

[Footnote 8: See Appendix, Essay B.]

[Footnote 9: _Hist. Ind. Sc._ b. ii. Additions to 3rd Ed.]

[Footnote 10: See these views further discussed in the Appendix, Essay

C.]

CHAPTER IV.

ARISTOTLE.

The views of Aristotle with regard to the foundations of human

knowledge are very different from those of his tutor Plato, and are

even by himself put in opposition to them. He dissents altogether

from the Platonic doctrine that Ideas are the true materials of our

knowledge; and after giving, respecting the origin of this doctrine,

the account which we quoted in the last chapter, he goes on to reason

against it. "Thus," he says[11], "they devised Ideas of all things

which are spoken of as universals: much as if any one having to count a

number of objects, should think that he could not do it while they were

few, and should expect to count them by making them more numerous. For

the kinds of things are almost more numerous than the special sensible

objects, by seeking the causes of which they were led to their Ideas."

He then goes on to urge several other reasons against the assumption of

Ideas and the use of them in philosophical researches.

Aristotle himself establishes his doctrines by trains of reasoning. But

reasoning must proceed from certain First Principles; and the question

then arises, Whence are these First Principles obtained? To this he

replies, that they are the result of _Experience_, and he even employs

the same technical expression by which we at this day describe the

process of collecting these principles from observed facts;--that they

are obtained by _Induction_. I have already quoted passages in which

this statement is made[12]. "The way of reasoning," he says[13], "is

the same in philosophy, and in any art or science: we must collect

the _facts_ (τὰ ὑπὰρχοντα), and the things to which the facts happen,

and must have as large a supply of these as possible, and then we must

examine them according to the terms of our syllogisms." ... "There are

peculiar principles in each science; and in each case these principles

must be obtained from _experience_. Thus astronomical observation

supplies the principles of astronomical science. For the phenomena

being rightly taken, the demonstrations of astronomy were discovered;

and the same is the case with any other Art or Science. So that if

the facts in each case be taken, it is our business to construct the

demonstrations. For if _in our natural history_ (κατὰ τὰν ἱστορί αν)

we have omitted none of the facts and properties which belong to the

subject, we shall learn what we can demonstrate and what we cannot."

And again[14], "It is manifest that if any sensation be wanting, there

must be some knowledge wanting, which we are thus prevented from

having. For we acquire knowledge either _by Induction_ (ἐπαγωγῆ) or

by Demonstration: and Demonstration is from universals, but Induction

from particulars. It is impossible to have universal theoretical

propositions except by Induction: and we cannot make inductions without

having sensation; for sensation has to do with particulars."

It is easy to show that Aristotle uses the term _Induction_, as we use

it, to express the process of collecting a general proposition from

particular cases in which it is exemplified. Thus in a passage which

we have already quoted[15], he says, "Induction, and Syllogism from

Induction, is when we attribute one extreme term to the middle by means

of the other." The import of this technical phraseology will further

appear by the example which he gives: "We find that several animals

which are deficient in bile are long-lived, as man, the horse, the

mule; hence we infer that _all_ animals which are deficient in bile are

long-lived."

We may observe, however, that both Aristotle's notion of induction,

and many other parts of his philosophy, are obscure and imperfect, in

consequence of his refusing to contemplate ideas as something distinct

from sensation. It thus happens that he always assumes the ideas

which enter into his proposition as _given_; and considers it as the

philosopher's business to determine whether such propositions are true

or not: whereas the most important feature in induction is, as we have

said, the _introduction_ of a new idea, and not its employment when

once introduced. That the mind in this manner gives unity to that which

is manifold,--that we are thus led to speculative principles which have

an evidence higher than any others,--and that a peculiar sagacity in

some men seizes upon the conceptions by which the facts may be bound

into true propositions,--are doctrines which form no essential part

of the philosophy of the Stagirite, although such views are sometimes

recognized, more or less clearly, in his expressions. Thus he says[16],

"There can be no knowledge when the sensation does not continue in

the mind. For this purpose, it is necessary both to perceive, and to

have some _unity_ in the mind (αἰσθανομένοις εχειν ἔν τι[17] ἐν τῇ

ψυχῇ); and many such perceptions having taken place, some difference

is then perceived: and from the remembrance of these arises Reason.

Thus from Sensation comes Memory, and from Memory of the same thing

often repeated comes Experience: for many acts of Memory make up one

Experience. And from Experience, or from any Universal Notion which

takes a permanent place in the mind,--from the _unity in the manifold_,

the same some one thing being found in many facts,--springs the first

principle of Art and of Science; of Art, if it be employed about

production; of Science, if about existence."

I will add to this, Aristotle's notice of _Sagacity_; since, although

little or no further reference is made to this quality in his

philosophy, the passage fixes our attention upon an important step in

the formation of knowledge. "Sagacity" (ἀγχίνοια), he says[18], "is a

hitting by guess (εὐστοχία τις) upon the middle term (the conception

common to two cases) in an inappreciable time. As for example, if any

one seeing that the bright side of the moon is always towards the sun,

suddenly perceives why this is; namely, because the moon shines by the

light of the sun:--or if he sees a person talking with a rich man, he

guesses that he is borrowing money;--or conjectures that two persons

are friends, because they are enemies of the same person."--To consider

only the first of these examples;--the conception here introduced,

that of a body shining by the light which another casts upon it, is

not contained in the observed facts, but introduced by the mind. It

is, in short, that conception which, in the act of induction, the mind

superadds to the phenomena as they are presented by the senses: and to

invent such appropriate conceptions, such "eustochies," is, indeed, the

precise office of inductive sagacity.

At the end of this work (the _Later Analytics_) Aristotle ascribes

our knowledge of principles to Intellect (νοῦς), or, as it appears

necessary to translate the word, _Intuition_[19]. "Since, of our

intellectual habits by which we aim at truth, some are always true, but

some admit of being false, as Opinion and Reasoning, but Science and

Intuition are always true; and since there is nothing which is more

certain than Science except Intuition; and since Principles are better

known to us than the Deductions from them; and since all Science is

connected by reasoning, we cannot have Science respecting Principles.

Considering this then, and that the beginning of Demonstration cannot

be Demonstration, nor the beginning of Science, Science; and since, as

we have said, there is no other kind of truth, Intuition must be the

beginning of Science."

What is here said, is, no doubt, in accordance with the doctrines which

we have endeavoured to establish respecting the nature of Science,

if by this _Intuition_ we understand that contemplation of certain

Fundamental Ideas, which is the basis of all rigorous knowledge. But

notwithstanding this apparent approximation, Aristotle was far from

having an habitual and practical possession of the principles which he

thus touches upon. He did not, in reality, construct his philosophy by

giving Unity to that which was manifold, or by seeking in Intuition

principles which might be the basis of Demonstration; nor did he

collect, in each subject, fundamental propositions by an induction

of particulars. He rather endeavoured to divide than to unite; he

employed himself, not in combining facts, but in analysing notions;

and the criterion to which he referred his analysis was, not the facts

of our experience, but our habits of language. Thus his opinions

rested, not upon sound inductions, gathered in each case from the

phenomena by means of appropriate Ideas; but upon the loose and vague

generalizations which are implied in the common use of speech.

Yet Aristotle was so far consistent with his own doctrine of the

derivation of knowledge from experience, that he made in almost

every province of human knowledge, a vast collection of such special

facts as the experience of his time supplied. These collections are

almost unrivalled, even to the present day, especially in Natural

History; in other departments, when to the facts we must add the right

Inductive Idea, in order to obtain truth, we find little of value

in the Aristotelic works. But in those parts which refer to Natural

History, we find not only an immense and varied collection of facts and

observations, but a sagacity and acuteness in classification which it

is impossible not to admire. This indeed appears to have been the most

eminent faculty in Aristotle's mind.

The influence of Aristotle in succeeding ages will come under our

notice shortly.

FOOTNOTES:

[Footnote 11: _Metaph._ xii. 4.]

[Footnote 12: _Hist. Ind. Sc._ b. i. c. iii. sect. 2.]

[Footnote 13: _Analyt. Prior._ i. 30.]

[Footnote 14: _Analyt. Post._ i. 18.]

[Footnote 15: _Analyt. Prior._ ii. 23, περὶ τῆς ἐπαγωγῆς.]

[Footnote 16: _Analyt. Post._ ii. 19.]

[Footnote 17: But the best reading seems to be not ἔν τι but ἔτι:

and the clause must be rendered "both to perceive and to retain the

perception in the mind." This correction does not disturb the general

sense of the passage, that the first principles of science are obtained

by finding the One in the Many.]

[Footnote 18: _Analyt. Post._ i. 34.]

[Footnote 19: _Ibid._ ii. 19.]

CHAPTER V.

ADDITIONAL REMARKS ON ARISTOTLE.

1. One of the most conspicuous points in Aristotle's doctrines as

bearing upon the philosophy of Science is his account of that mode of

attaining truth which is called _Induction_; for we are accustomed

to consider Induction as the process by which our Sciences have been

formed; and we call them collectively the _Inductive Sciences_.

Aristotle often speaks of Induction, as for instance, when he says that

Socrates introduced the frequent use of it. But the cardinal passage

on this subject is in his _Analytics_, in which he compares Syllogism

and Induction as two modes of drawing conclusions[20]. He there says

that all belief arises either from Syllogism or from Induction: and

adds that Induction is, when by means of one extreme term we infer

the other extreme to be true of the middle term. The example which

he gives is this: knowing that particular animals are long-lived, as

elephant, horse, mule; and finding that these animals agree in having

no gall-bladder; we infer, by _Induction_, that _all_ animals which

have no gall-bladder are long-lived. This may be done, he says, if the

middle and the second extreme are convertible: as the following formal

statement may show.

Elephant, horse, mule, &c. are long-lived.

Elephant, horse, mule, &c. are all gall-less.

If we might convert this proposition, and say

All gall-less animals are as elephant, horse, mule, &c.:

we might infer _syllogistically_ that

All gall-less animals are long-lived.

And though we cannot infer this syllogistically, we infer it by

Induction, when we have a sufficient amount of instances[21].

I have already elsewhere given this account of Induction, as a process

employed in the formation of our knowledge[22]. What I have now to

remark concerning Aristotle is, that it does not appear to have

occurred to him, that in establishing such a proposition as that which

he gives as his instance, the main difficulty is the _discovery_ of

a _middle term_ which will allow us to frame such a proposition as

we need. The zoologist who wanted to know what kind of animals are

long-lived, might guess long before he guessed that the absence of the

gall-bladder supplied the requisite middle term; (if the proposition

were true; which it is not.) And in like manner in other cases, it

is difficult to find a middle term, which enables us to collect a

proposition by Induction. And herein consists the imperfection of his

view of the subject; which considers the main point to be the proof

of the proposition when the conceptions are _given_, whereas the main

point really is, the _discovery_ of conceptions which will make a true

proposition possible.

2. Since the main characteristic of the steps which have occurred in

the formation of the physical sciences, is not merely that they are

propositions collected by Induction, but by the introduction of a _new_

conception; it has been suggested that it is not a characteristic

designation of these Sciences to call them _Inductive Sciences_. Almost

every discovery involves in it the introduction of a new conception,

as the element of a new proposition; and the novelty of the conception

is more characteristic of the stages of discovery than the inductive

application of it. Hence as bearing upon the Philosophy of Discovery,

the statements of Aristotle concerning Induction, though acute and

valuable, are not so valuable as they might seem. Even Francis Bacon,

it has been asserted, erred in the same way (and of course with less

excuse) in asserting Induction, of a certain kind, to be the great

instrument for the promotion of knowledge, and in overlooking the

necessity of the _Invention_ which gives Induction its value.

3. The invention or discovery of a conception by which many facts

of observation are conjoined so as to make them the materials of a

proposition, is called in Plato, as we have seen, _finding the One in

the Many_.

In the passage quoted from the _Later Analytics_, Aristotle uses the

same expression, and speaks very justly respecting the formation of

knowledge. Indeed the _Titles_ of the chapters of this and many parts

of Aristotle's works would lead us to expect just such a Philosophy

of Discovery as is the object of our study at present. Thus we have,

_Anal. Post._ B. II. chap. 13: "How we are to hunt (θηρεύειν) the

predications of a Definition." Chap. 14: "Precepts for the invention

of Problems and of a Middle Term:" and the like. But when we come to

read these chapters, they contain little that is of value, and resolve

themselves mostly into permutations of Aristotle's logical phraseology.

4. The part of the Aristotelian philosophy which has most permanently

retained its place in modern Sciences is a part of which a use has been

made quite different from that which was originally contemplated. The

"Five words" which are explained in the Introduction to Aristotle's

_Categories_: namely, the words _Genus_, _Species_, _Difference_,

_Property_, _Accident_, were introduced mainly that they might be used

in the propositions of which Syllogisms consist, and might thus be the

elements of reasoning. But it has so happened that these words are

rarely used in Sciences of Reasoning, but are abundantly and commonly

used in the Sciences of Classification, as I have explained in

speaking of the Classificatory Sciences[23].

5. Of Aristotle's actual contributions to the Physical Sciences I have

spoken in the History of those Sciences[24]. I have[25] stated that

he conceived the globular form of the earth so clearly and gave so

forcibly the arguments for that doctrine, that we may look upon him as

the most effective teacher of it. Also in the Appendix to that History,

published in the third edition, I have given Aristotle's account of the

Rainbow, as a further example of his industrious accumulation of facts,

and of his liability to error in his facts.

6. We do not find Aristotle so much impressed as we might have expected

by that great monument of Grecian ingenuity, the theory of epicycles

and excentrics which his predecessor Plato urged so strongly upon the

attention of his contemporaries. Aristotle proves, as I have said,

the globular form of the earth by good and sufficient arguments. He

also proves by arguments which seem to him quite conclusive[26], that

the earth is in the center of the universe, and immoveable. As to the

motions of the rest of the planets, he says little. The questions

of their order, and their distances, and the like, belong, he says,

to Astrology[27]. He remarks only that the revolution of the heaven

itself, the outermost revolution, is simple and the quickest of all:

that the revolutions of the others are slower, each moving in a

direction opposite to the heaven in its own circle: and that it is

reasonable that those which are nearest to the first revolution should

take the longest time in describing their own circle, and those that

are furthest off, the least time, and the intermediate ones in the

order of their distances, "as also the mathematicians show."

In the _Metaphysics_[28] he enumerates the circular movements which

had been introduced by the astronomers Eudoxus and Calippus for the

explanation of the phenomena presented by the sun, moon and planets.

These, he says, amount to fifty-five; and this, he says, must be the

number of essences and principles which exist in the universe.

7. In the Sciences of Classification, and especially in the

classification of animals, higher claims have been made for Aristotle,

which I have discussed in the History[29]. I have there attempted to

show that Aristotle's classification, inasmuch as it enumerates all

the parts of animals, may be said to contain the _materials_ of every

subsequent classification: but that it cannot be said to anticipate

any modern system, because the different grades of classification are

not made _subordinate_ to one another as a _system_ of classification

requires. I have the satisfaction of finding Mr. Owen agreeing with me

in these views[30].

8. Francis Bacon's criticism on Aristotle which I have quoted in the

Appendix to the History[31], is severe, and I think evidently the

result of prejudice. He disparages Aristotle in comparison with the

other philosophers of Greece. 'Their systems,' he says, 'had some

savour of experience, and nature, and bodily things; while the Physics

of Aristotle, in general, sound only of Logical Terms.

'Nor let anyone be moved by this: that in his books _Of Animals_,

and in his _Problems_, and in others of his tracts, there is often a

quoting of experiments. For he had made up his mind beforehand; and did

not consult experience in order to make right propositions and axioms,

but when he had settled his system to his will, he twisted experience

round and made her bend to his system.'

I do not think that this can be said with any truth. I know no

instances in which Aristotle has twisted experience round, and made

her bend to his system. In his _Problems_, he is so far from giving

dogmatical solutions of the questions proposed, that in most cases, he

propounds two or three solutions as mere suggestions and conjectures.

And both in his History of Animals, as I have said, and in others of

his works, the want of system gives them an incoherent and tumultuary

character, which even a false system would have advantageously removed;

for, as I have said elsewhere, it is easier to translate a false system

into a true one, than to introduce system into a mass of confusion.

9. It is curious that a fundamental error into which Aristotle fell in

his view of the conditions which determine the formation of Science

is very nearly the same as one of Francis Bacon's leading mistakes.

Aristotle says, that Science consists in knowing the _causes_ of

things, as Bacon aims at acquiring a knowledge of the _forms_ or

_essences_ of things and their qualities. But the history of all the

sciences teaches us that sciences do not begin with such knowledge, and

that in few cases only do they ever attain to it. Sciences begin by a

knowledge of the _laws_ of _phenomena_, and proceed by the discovery

of the scientific ideas by which the phenomena are colligated, as I

have shown in other works[32]. The discovery of causes is not beyond

the human powers, as some have taught. Those who thus speak disregard

the lessons taught by the history of Physical Astronomy, of Geology, of

Physical Optics, Thermotics and other sciences. But the discovery of

causes, and of the essential forms of qualities, is a triumph reserved

for the later stages of each Science, when the knowledge of the laws of

phenomena has already made great progress. It was not to be expected

that Aristotle would discern this truth, when, as yet, there was no

Science extant in which it had been exemplified. Yet in Astronomy, the

theory of epicycles and excentrics had immense value, and even has

still, as representing the laws of phenomena; while the attempt to find

in it, as Aristotle wished to do, the ultimate causes of the motions

of the universe, could only mislead. The Aristotelian maxim, which

sounds so plausible, and has been so generally accepted, that "to know

truly is to know the causes of things," is a bad guide in scientific

research. Instead of it we might substitute this: that "though we may

aspire to know at last _why_ things are, we must be content for a long

time with knowing _how_ they are."

10. Hence if we are asked whether Plato or Aristotle had the truer

views of the nature and property of Science, we must give the

preference to Plato; for though his notion of a real Intelligible

World, of which the Visible world was a fleeting and changeable shadow,

was extravagant, yet it led him to seek to determine the forms of the

Intelligible Things, which are really the laws of visible phenomena;

while Aristotle was led to pass lightly over such laws, because they

did not at once reveal the causes which produced the phenomena.

11. Aristotle, throughout his works, takes numerous occasions to

argue against Plato's doctrine of Ideas. Yet these Ideas, so far as

they were the Intelligible Forms of Visible Things, were really fit

objects of philosophical research; and the search after them had a

powerful influence in promoting the progress of Science. And we may

see in the effect of this search the answer to many of Aristotle's

strongest arguments. For instance, Aristotle says that Plato, by way of

explaining things, adds to them as many Ideas, and that this is just

as if a man having to reckon a large number, were to begin by adding

to it another large number. It is plain that to this we may reply,

that the adopting the Ideas of Cycles, along with the motions of the

Planets, does really explain the motions; and that the Cycles are not

simply added to the phenomena, but include and supersede the phenomena:

a finite number of Cycles include and represent an infinite number of

separate phenomena.

To Aristotle's argument that Ideas cannot be the Causes or Principles

of Things, we should reply, that though they cannot be this, they may

nevertheless be, and must be, the Conditions and Principles of our

Knowledge, which is what we want them to be.

I have given an account of the main features of Aristotle's philosophy,

so far as it concerns the Physical Sciences, in the History of the

Inductive Sciences, Book I.

FOOTNOTES:

[Footnote 20: _Analyt. Prior._ ii. 25.]

[Footnote 21: See on this subject Appendix, Essay D.]

[Footnote 22: See the chapter on Certain Characteristics of Scientific

Induction in the _Phil. Ind. Sc._ or in the _Nov. Org. Renov._]

[Footnote 23: _Phil. Ind. Sc._ b. viii. c. i. art. 11, or _Hist. Sc.

Id._ b. viii.]

[Footnote 24: B. i. c. xi. sect. 2.]

[Footnote 25: B. iii. c. i. sect. 9.]

[Footnote 26: _De Cælo_, ii. 13.]

[Footnote 27: _Ibid._ ii. 10.]

[Footnote 28: xii. 8.]

[Footnote 29: B. xvi. c. vi.]

[Footnote 30: _On the Classification of Mammalia, &c.: a Lecture

delivered at Cambridge_, May 10, 1859, p. 3.]

[Footnote 31: B. i. c. xi.]

[Footnote 32: _History of Scientific Ideas_, and _Novum Organum

Renovatum_.]

CHAPTER VI.

THE LATER GREEKS.

Thus while Plato was disposed to seek the essence of our knowledge

in Ideas alone, Aristotle, slighting this source of truth, looked to

Experience as the beginning of Science; and he attempted to obtain, by

division and deduction, all that Experience did not immediately supply.

And thus, with these two great names, began that struggle of opposite

opinions which has ever since that time agitated the speculative

world, as men have urged the claims of Ideas or of Experience to our

respect, and as alternately each of these elements of knowledge has

been elevated above its due place, while the other has been unduly

depressed. We shall see the successive turns of this balanced struggle

in the remaining portions of this review.

But we may observe that practically the influence of Plato predominated

rather than that of Aristotle, in the remaining part of the history

of ancient philosophy. It was, indeed, an habitual subject of dispute

among men of letters, whether the sources of true knowledge are

to be found in the Senses or in the Mind; the Epicureans taking

one side of this alternative, and the Academics another, while the

Stoics in a certain manner included both elements in their view. But

none of these sects showed their persuasion that the materials of

knowledge were to be found in the domain of Sense, by seeking them

there. No one appears to have thought of following the example of

Aristotle, and gathering together a store of observed facts. We may

except, perhaps, assertions belonging to some provinces of Natural

History, which were collected by various writers: but in these, the

mixed character of the statements, the want of discrimination in

the estimate of evidence, the credulity and love of the marvellous

which the authors for the most part displayed, showed that instead

of improving upon the example of Aristotle, they were wandering

further and further from the path of real knowledge. And while they

thus collected, with so little judgment, such statements as offered

themselves, it hardly appears to have occurred to any one to enlarge

the stores of observation by the aid of experiment; and to learn

what the laws of nature were, by trying what were their results in

particular cases. They used no instruments for obtaining an insight

into the constitution of the universe, except logical distinctions

and discussions; and proceeded as if the phenomena familiar to their

predecessors must contain all that was needed as a basis for natural

philosophy. By thus contenting themselves with the facts which the

earlier philosophers had contemplated, they were led also to confine

themselves to the ideas which those philosophers had put forth. For

all the most remarkable alternatives of hypothesis, so far as they

could be constructed with a slight and common knowledge of phenomena,

had been promulgated by the acute and profound thinkers who gave the

first impulse to philosophy: and it was not given to man to add much

to the original inventions of _their_ minds till he had undergone

anew a long discipline of observation, and of thought employed upon

observation. Thus the later authors of the Greek Schools became little

better than commentators on the earlier; and the commonplaces with

which the different schools carried on their debates,--the constantly

recurring argument, with its known attendant answer,--the distinctions

drawn finer and finer and leading to nothing,--render the speculations

of those times a _scholastic_ philosophy, in the same sense in which

we employ the term when we speak of the labours of the middle ages. It

will be understood that I now refer to that which is here my subject,

the opinions concerning our knowledge of nature, and the methods in

use for the purpose of obtaining such knowledge. Whether the moral

speculations of the ancient world were of the same stationary kind,

going their round in a limited circle, like their metaphysics and

physics, must be considered on some other occasion. [33] Mr. Grote,

in his very interesting discussion of Socrates's teaching, notices

also[34] the teaching of Hippocrates, which he conceives to have in

one respect the same tendency as the philosophy of Socrates; namely,

to turn away from the vague aggregate of doctrines and guesses which

constituted the Physical Philosophy of that time, and to pursue instead

a special and more practical course of inquiry: Hippocrates selecting

Medicine and Socrates selecting Ethics. By this limitation of their

subject, they avoided some of the errors of their predecessors. For,

as Mr. Grote has also remarked, "the earlier speculators, Anaxagoras,

Empedocles, Democritus, the Pythagoreans, all had still present to

their minds the vast and undivided problems which have been transmitted

down from the old poets; bending their minds to the invention of some

system which would explain them all at once, or assist the imagination

in conceiving both how the Kosmos first began and how it continued to

move on." There could be no better remedy for this ambitious error of

the human mind than to have a definite subject of study, such as the

diseases and the health of the human body. Accordingly, we see that the

study of medicine did draw its cultivators away from this ancient but

unprofitable field. Hippocrates[35] condemns those who, as Empedocles,

set themselves to make out what man was from the beginning, how he

began first to exist, and in what manner he was constructed. This is,

he says, no part of medicine. In like manner he blames and refutes

those who make some simple element, Hot, or Cold, or Moist, or Dry, the

cause of diseases, and give medical precepts professing to be founded

on this hypothesis.

These passages are marked by the prudence which practical study

suggests to a calm and clear-sighted man. They can hardly be said to

have opened the way to a Science of Medicine; for in the sense in which

we here use the word _Science_, namely, a collection of general truths

inferred from facts by successive discoverers, we have even yet no

Science of Medicine. The question with regard to the number and nature

of the Elements of which bodies are composed began to be agitated, as

we have seen, at a very early period of Greek philosophy, and continued

long to be regarded as a chief point of physiological doctrine. In

Galen's work we have a treatise entitled, _On the Elements according

to Hippocrates_; and the writer explains[36] that though Hippocrates

has not written any work with the title _On the Elements_, yet that

he has in his _Treatise on the Nature of Man_ shown his opinion on

that subject. That the doctrine of the Four Elements, Hot, Cold,

Moist, Dry, subsisted long in the schools, we have evidence in Galen.

He tells us[37] that when he was a student of nineteen years old a

teacher urged this lore upon him, and regarded him as very contentious

and perverse, because he offered objections to it. His account of the

Dialogue between him and the teacher is curious. But in Hippocrates the

doctrine of these four elements is replaced, in a great measure, by the

doctrine of the Four Humours of which the human body is constituted;

namely, Blood, Phlegm, Yellow Bile and Black Bile. Galen dwells with

emphasis upon Hippocrates's proof that there must be more than one such

element[38].

"What," he asks, "is the method of finding the Elements of bodies?

There can, in my opinion, be no other than that which was introduced by

Hippocrates; namely, we must inquire whether there be only one element,

everywhere the same in kind, or whether there are more than one,

various and unlike each other. And if the Element be not one only, but

several, various and dissimilar, we must inquire in the second place,

how many elements there are, and what, and of what kind they are, and

how related in their association.

"Now that the First Element is not one only of which both our bodies

and those of all other creatures were produced, Hippocrates shows

from these considerations. And it is better first to put down his own

expressions and then to expound them. 'I assert that if man consisted

of one element only he could not fall sick; for there would be nothing

which could derange his health, if he were all of one Element.'"

The doctrine of One Element did not prevail much after the time of

Hippocrates: the doctrine of Four Elements continued, as I have said,

long to hold possession of the Schools, but does not appear as an

important part of the doctrine of Hippocrates. The doctrine of the Four

Humours (Blood, Phlegm, Yellow Bile and Black Bile) is more peculiarly

his, and long retained its place as a principle of physiological

Science.

But we are here not so much concerned with his discoveries in medicine

as with his views respecting the method of acquiring sound knowledge,

and in this respect, as has been said, he recommends by his practice

a prudent limitation of the field of inquiry, a rejection of wide,

ambitious, general assertions, and a practical study of his proper

field.

In ascribing these merits to Hippocrates's medical speculations as

to the ethical speculations of his contemporary Socrates, we assign

considerable philosophical value to Hippocrates, no less than to

Socrates. These merits were at that time the great virtues of physical

as well as of ethical philosophy. But, as Mr. Grote well observes, the

community of character which then subsisted between the physical and

ethical speculations prevailing at that time, ceased to obtain in later

times. Indeed, it ceased to exist just at that time, in consequence of

the establishment of scientific astronomy by the exertions of Plato

and his contemporaries. From that time the Common Sense (as we call it)

of a man like Socrates, though it might be a good guide in ethics, was

not a good guide in physics. I have shown elsewhere[39] how the Common

Sense of Socrates was worthless in matters of astronomy. From that time

one of the great intellectual lessons was, that in order to understand

the external world, we must indeed observe carefully, but we must also

guess boldly. Discovery here required an inventive mind like Plato's

to deal with and arrange new and varied facts. But in ethics all the

facts were old and familiar, and the generalizations of language by

which they were grouped as Virtues and Vices, and the like, were common

and well-known words. Here was no room for invention; and thus in the

ethical speculations of Socrates or of any other moral teacher, we are

not to look for any contributions to the Philosophy of Discovery.

Nor do I find anything on this subject among later Greek writers,

beyond the commendation of such intellectual virtues as Hippocrates and

Galen, and other medical writers, schooled by the practice of their

art, enjoined and praised. But before we quit the ancients I will point

out some peculiarities which may be noticed in the Roman disciples of

the Greek philosophy.

FOOTNOTES:

[Footnote 33: The remainder of this chapter is new in the present

edition.]

[Footnote 34: _Hist. of Greece_, Part ii. chap. 68.]

[Footnote 35: _De Antiqua Medicina_, c. 20.]

[Footnote 36: Lib. i. c. 9.]

[Footnote 37: _De Elem._ i. 6.]

[Footnote 38: In former editions I have not done justice to this

passage.]

[Footnote 39: _Hist. Ind. Sc._ Addition to Introduction in Third

Edition.]

CHAPTER VII.

THE ROMANS.

The Romans had no philosophy but that which they borrowed from the

Greeks; and what they thus received, they hardly made entirely their

own. The vast and profound question of which we have been speaking,

the relation between Existence and our Knowledge of what exists, they

never appear to have fathomed, even so far as to discern how wide and

deep it is. In the development of the ideas by which nature is to be

understood, they went no further than their Greek masters had gone,

nor indeed was more to be looked for. And in the practical habit of

accumulating observed facts as materials for knowledge, they were much

less discriminating and more credulous than their Greek predecessors.

The descent from Aristotle to Pliny, in the judiciousness of the

authors and the value of their collections of facts, is immense.

Since the Romans were thus servile followers of their Greek teachers,

and little acquainted with any example of new truths collected from

the world around them, it was not to be expected that they could have

any just conception of that long and magnificent ascent from one set

of truths to others of higher order and wider compass, which the

history of science began to exhibit when the human mind recovered

its progressive habits. Yet some dim presentiment of the splendid

career thus destined for the intellect of man appears from time to

time to have arisen in their minds. Perhaps the circumstance which

most powerfully contributed to suggest this vision, was the vast

intellectual progress which they were themselves conscious of having

made, through the introduction of the Greek philosophy; and to this

may be added, perhaps, some other features of national character. Their

temper was too stubborn to acquiesce in the absolute authority of the

Greek philosophy, although their minds were not inventive enough to

establish a rival by its side. And the wonderful progress of their

political power had given them a hope in the progress of man which

the Greeks never possessed. The Roman, as he believed the fortune of

his State to be destined for eternity, believed also in the immortal

destiny and endless advance of that Intellectual Republic of which he

had been admitted a denizen.

It is easy to find examples of such feelings as I have endeavoured

to describe. The enthusiasm with which Lucretius and Virgil speak of

physical knowledge, manifestly arises in a great measure from the

delight which they had felt in becoming acquainted with the Greek

theories.

Me vero primum dulces ante omnia Musæ

Quarum sacra fero ingenti perculsus amore

Accipiant, cœlique vias et sidera monstrent,

Defectus Solis varios, Lunæque labores!...

Felix qui potuit rerum cognoscere causas!

Ye sacred Muses, with whose beauty fir'd,

My soul is ravisht and my brain inspir'd:

Whose Priest I am, whose holy fillets wear,

Would you your Poet's first petition hear,

Give me the ways of wand'ring stars to know,

The depth of Heaven above and Earth below;

Teach me the various labours of the Moon,

And whence proceed th' eclipses of the Sun;

Why flowing Tides prevail upon the main,

And in what dark abyss they shrink again;

What shakes the solid Earth; what cause delays

The Summer Nights; and shortens Winter Days....

Happy the man who, studying Nature's Laws,

Through known effects can trace the secret cause!

Ovid[40] expresses a similar feeling.

Felices animos quibus hæc cognoscere primis

Inque domos superas scandere cura fuit!...

Admovere oculis distantia sidera nostris

Ætheraque ingenio supposuere suo.

Sic petitur cœlum: non ut ferat Ossam Olympus

Summaque Peliacus sidera tanget apex.

Thrice happy souls! to whom 'twas given to rise

To truths like these, and scale the spangled skies!

Far distant stars to clearest view they brought,

And girdled ether with their chain of thought.

So heaven is reached:--not as of old they tried

By mountains piled on mountains in their pride.

And from the whole tenour of these and similar passages, it is evident

that the intellectual pleasure which arises from our first introduction

to a beautiful physical theory had a main share in producing this

enthusiasm at the contemplation of the victories of science; although

undoubtedly the moral philosophy, which was never separated from the

natural philosophy, and the triumph over superstitious fears, which

a knowledge of nature was supposed to furnish, added warmth to the

feeling of exultation.

We may trace a similar impression in the ardent expressions which

Pliny[41] makes use of in speaking of the early astronomers, and which

we have quoted in the _History_. "Great men! elevated above the common

standard of human nature, by discovering the laws which celestial

occurrences obey, and by freeing the wretched mind of man from the

fears which eclipses inspired."

This exulting contemplation of what science had done, naturally led the

mind to an anticipation of further achievements still to be performed.

Expressions of this feeling occur in Seneca, and are of the most

remarkable kind, as the following example will show[42]:

"Why do we wonder that comets, so rare a phenomenon, have not yet had

their laws assigned?--that we should know so little of their beginning

and their end, when their recurrence is at wide intervals? It is not

yet fifteen hundred years since Greece,

Stellis numeros et nomina fecit,

'reckoned the stars, and gave them names.' There are still many nations

which are acquainted with the heavens by sight only; which do not yet

know why the moon disappears, why she is eclipsed. It is but lately

that among us philosophy has reduced these matters to a certainty. The

day shall come when the course of time and the labour of a maturer age

shall bring to light what is yet concealed. One generation, even if it

devoted itself to the skies, is not enough for researches so extensive.

How then can it be so, when we divide this scanty allowance of years

into no equal shares between our studies and our vices? These things

then must be explained by a long succession of inquiries. We have but

just begun to know how arise the morning and evening appearances,

the stations, the progressions, and the retrogradations of the fixed

stars which put themselves in our way;--which appearing perpetually

in another and another place compel us to be curious. Some one will

hereafter demonstrate in what region the comets wander; why they move

so far asunder from the rest; of what size and nature they are. Let

us be content with what we have discovered: let posterity contribute

its share to truth." Again he adds[43] in the same strain: "Let us

not wonder that what lies so deep is brought out so slowly. How many

animals have become known for the first time in this age! And the

members of future generations shall know many of which we are ignorant.

Many things are reserved for ages to come, when our memory shall

have passed away. The world would be a small thing indeed, if it did

not contain matter of inquiry _for_ all the world. Eleusis reserves

something for the second visit of the worshipper. _So too Nature

does not at once disclose all_ HER _mysteries_. We think ourselves

initiated; we are but in the vestibule. The arcana are not thrown open

without distinction and without reserve. This age will see some things;

that which comes after us, others."

While we admire the happy coincidence of these conjectures with the

soundest views which the history of science teaches us, we must not

forget that they are merely conjectures, suggested by very vague

impressions, and associated with very scanty conceptions of the laws

of nature. Seneca's _Natural Questions_, from which the above extract

is taken, contains a series of dissertations on various subjects of

Natural Philosophy; as Meteors, Rainbows, Lightnings, Springs, Rivers,

Snow, Hail, Rain, Wind, Earthquakes and Comets. In the whole of these

dissertations, the statements are loose, and the explanations of little

or no value. Perhaps it may be worth our while to notice a case in

which he refers to an observation of his own, although his conclusion

from it be erroneous. He is arguing[44] against the opinion that

Springs arise from the water which falls in rain. "In the first place,"

he says, "I, a very diligent digger in my vineyard, affirm that no rain

is so heavy as to moisten the earth to the depth of more than ten feet.

All the moisture is consumed in this outer crust, and descends not to

the lower part." We have here something of the nature of an experiment;

and indeed, as we may readily conceive, the instinct which impels man

to seek truth by experiment can never be altogether extinguished.

Seneca's experiment was deprived of its value by the indistinctness of

his ideas, which led him to rest in the crude conception of the water

being "consumed" in the superficial crust of the earth.

It is unnecessary to pursue further the reasonings of the Romans on

such subjects, and we now proceed to the ages which succeeded the fall

of their empire.

FOOTNOTES:

[Footnote 40: Lib. i. _Fast._]

[Footnote 41: _Hist. Nat._ i. 75.]

[Footnote 42: _Quæst. Nat._ vii. 25.]

[Footnote 43: _Quæst. Nat._ vii. 30, 31.]

[Footnote 44: _Ibid._ iii. 7.]

CHAPTER VIII.

ARABIAN PHILOSOPHERS.

I have noticed certain additions to Physical Science made by the

Arabians; namely, in Astronomy[45]. The discovery of the motion of

the Sun's Apogee by Albategnius, and the discovery of the Moon's

_Variation_ by Aboul-Wefa; and in Optics[46] the assertion of Alhazen

that the angle of refraction is not proportional to the angle of

incidence, as Ptolemy had supposed: and certain steps in the philosophy

of vision. We must also suppose, as the Arabic word _alkali_ reminds

us, that the Arabians contributed to lay the foundations of chemistry.

The question which we have here to ask is, whether the Arabians made

any steps beyond their predecessors in the philosophy of discovery.

And to this question, I conceive the answer must be this: that among

them as among the Greeks, those who practically observed nature, and

especially those who made discoveries in Science, must have had a

practical acquaintance with some of the maxims which are exemplified

in the formation of Science. To discover that the Apogee of the Sun

was 17 degrees distant from the point where Ptolemy had placed it,

Albategnius made careful observations, and referred them to the theory

of the eccentric, so as to verify or correct that theory. And when, in

the eleventh century, Arzachel found the Apogee to be less advanced

than Albategnius had found it, he proceeded again to correct the

theory by introducing a new movement of the equinoctial points, which

was called the _Trepidation_. It appeared afterwards, however, that,

in doing this, he had had too much confidence in the observations of

his predecessors, and that no such movement as the Trepidation really

existed. In like manner to correct Ptolemy's law of refraction, Alhazen

had recourse to experiment: but he did not put his experiments in the

form of a Table, as Ptolemy had done. If he had done this, he might

possibly have discovered the law of sines, which Snell afterwards

discovered.

But though the Arabian philosophers thus, in some cases, observed

facts, and referred those facts to general mathematical laws, it does

not appear that they were led to put in any new or striking general

form such maxims as this: That the progress of Science consists in the

exact observation of facts and in colligating them by ideas. Those of

them who were dissatisfied with the existing philosophy as barren and

useless (for instance Algazel[47]), were led to point at the faults

and contradictions of that philosophy, but did not attempt, so far

as I know, to substitute for it anything better. If they rejected

Aristotle's _Organon_, they did not attempt to construct a new Organon

for themselves.

Indeed they do not appear even to have had sufficient confidence in the

real truth of the astronomical theories which they had adopted from the

Greeks, always to correct and extend those where their observations

showed that they required correction and extension. Sometimes they did

this, but not generally enough. When Arzachel found by observation

the Apogee of the Sun to be situated too far back, he ventured to

correct Ptolemy's statement of its motion. But when Aboul-Wefa had

really discovered the _Variation_ of the Moon's motion, he did not

express it by means of an epicycle. If he had done so, he would have

made it unnecessary for Tycho Brahe at a later period to make the same

discovery.

The moral of this incident is the same moral which we have perpetually

to note as taught us at every step by the history of Science:--namely,

the necessity of constant, careful and exact observation of Facts; and

the advantage of devising a Theory, (even if it have to be afterwards

rejected,) by which the Facts shall be bound together into a coherent

whole.

FOOTNOTES:

[Footnote 45: _Hist. Ind. Sc._ b. iii. c. iv. sect. 8.]

[Footnote 46: _Ibid._ b. ix. c. ii.]

[Footnote 47: See _Hist. Ind. Sc._ b. iv. c. i.]

CHAPTER IX.

THE SCHOOLMEN OF THE MIDDLE AGES.

In the _History of the Sciences_ I have devoted a Book to the state

of Science in the middle ages, and have endeavoured to analyse the

intellectual defects of that period. Among the characteristic features

of the human mind during those times, I have noticed Indistinctness of

Ideas, a Commentatorial Spirit, Mysticism, and Dogmatism. The account

there given of this portion of the history of man belongs, in reality,

rather to the History of Ideas than to the History of Progressive

Science. For, as we have there remarked, theoretical Science was,

during the period of which we speak, almost entirely stationary; and

the investigation of the causes of such a state of things may be

considered as a part of that review in which we are now engaged, of the

vicissitudes of man's acquaintance with the methods of discovery. But

when we offered to the world a history of science, to leave so large a

chasm unexplained, would have made the series of events seem defective

and broken; and the survey of the Middle Ages was therefore inserted.

I would beg to refer to that portion of the former work the reader who

wishes for information in addition to what is here given.

The Indistinctness of Ideas and the Commentatorial Disposition of those

ages have already been here brought under our notice. Viewed with

reference to the opposition between Experience and Ideas, on which

point, as we have said, the succession of opinions in a great measure

turns, it is clear that the commentatorial method belongs to the ideal

side of the question: for the commentator seeks for such knowledge

as he values, by analysing and illustrating what his author has said;

and, content with this material of speculation, does not desire to

add to it new stores of experience and observation. And with regard

to the two other features in the character which we gave to those

ages, we may observe that Dogmatism demands for philosophical theories

the submission of mind, due to those revealed religious doctrines

which are to guide our conduct and direct our hopes: while Mysticism

elevates ideas into realities, and offers them to us as the objects

of our religious regard. Thus the Mysticism of the middle ages and

their Dogmatism alike arose from not discriminating the offices of

theoretical and practical philosophy. Mysticism claimed for ideas the

dignity and reality of principles of moral action and religious hope:

Dogmatism imposed theoretical opinions respecting speculative points

with the imperative tone of rules of conduct and faith.

If, however, the opposite claims of theory and practice interfered

with the progress of science by the confusion they thus occasioned,

they did so far more by drawing men away altogether from mere physical

speculations. The Christian religion, with its precepts, its hopes, and

its promises, became the leading subject of men's thoughts; and the

great active truths thus revealed, and the duties thus enjoined, made

all inquiries of mere curiosity appear frivolous and unworthy of man.

The Fathers of the Church sometimes philosophized ill; but far more

commonly they were too intent upon the great lessons which they had to

teach, respecting man's situation in the eyes of his Heavenly Master,

to philosophize at all respecting things remote from the business of

life and of no importance in man's spiritual concerns.

Yet man has his intellectual as well as his spiritual wants. He has

faculties which demand systems and reasons, as well as precepts and

promises. The Christian doctor, who knew so much more than the heathen

philosopher respecting the Creator and Governor of the universe, was

not long content to know or to teach less, respecting the universe

itself. While it was still maintained that Theology was the only

really important study, Theology was so extended and so fashioned as to

include all other knowledge: and after no long time, the Fathers of the

Church themselves became the authors of systems of universal knowledge.

But when this happened, the commentatorial spirit was still in its

full vigour. The learned Christians could not, any more than the

later Greeks or the Romans, devise, by the mere force of their own

invention, new systems, full, comprehensive, and connected, like those

of the heroic age of philosophy. The same mental tendencies which led

men to look for speculative coherence and completeness in the view of

the universe, led them also to admire and dwell upon the splendid and

acute speculations of the Greeks. They were content to find, in those

immortal works, the answers to the questions which their curiosity

prompted; and to seek what further satisfaction they might require,

in analysing and unfolding the doctrines promulgated by those great

masters of knowledge. Thus the Christian doctors became, as to general

philosophy, commentators upon the ancient Greek teachers.

Among these, they selected Aristotle as their peculiar object of

admiration and study. The vast store, both of opinions and facts, which

his works contain, his acute distinctions, his cogent reasons in some

portions of his speculations, his symmetrical systems in almost all,

naturally commended him to the minds of subtle and curious men. We

may add that Plato, who taught men to contemplate Ideas separate from

Things, was not so well fitted for general acceptance as Aristotle, who

rejected this separation. For although the due apprehension of this

opposition of Ideas and Sensations is a necessary step in the progress

of true philosophy, it requires a clearer view and a more balanced mind

than the common herd of students possess; and Aristotle, who evaded the

necessary perplexities in which this antithesis involves us, appeared,

to the temper of those times, the easier and the plainer guide of the

two.

The Doctors of the middle ages having thus adopted Aristotle as

their master in philosophy, we shall not be surprised to find them

declaring, after him, that experience is the source of our knowledge

of the visible world. But though, like the Greeks, they thus talked of

experiment, like the Greeks, they showed little disposition to discover

the laws of nature by observation of facts. This barren and formal

recognition of experience or sensation as one source of knowledge,

not being illustrated by a practical study of nature, and by real

theoretical truths obtained by such a study, remained ever vague,

wavering, and empty. Such a mere acknowledgment cannot, in any times,

ancient or modern, be considered as indicating a just apprehension of

the true basis and nature of science.

In imperfectly perceiving how, and how far, experience is the source of

our knowledge of the external world, the teachers of the middle ages

were in the dark; but so, on this subject, have been almost all the

writers of all ages, with the exception of those who in recent times

have had their minds enlightened by contemplating philosophically the

modern progress of science. The opinions of the doctors of the middle

ages on such subjects generally had those of Aristotle for their basis;

but the subject was often still further analysed and systematized, with

an acute and methodical skill hardly inferior to that of Aristotle

himself.

The Stagirite, in the beginning of his _Physics_, had made the

following remarks. "In all bodies of doctrine which involve principles,

causes, or elements, Science and Knowledge arise from the knowledge

of these; (for we then consider ourselves to _know_ respecting any

subject, when we know its first cause, its first principles, its

ultimate elements.) It is evident, therefore, that in seeking a

knowledge of nature, we must first know what are its principles. But

the course of our knowledge is, from the things which are better known

and more manifest to us, to the things which are more certain and

evident in nature. For those things which are most evident in truth,

are not most evident to us. [And consequently we must advance from

things obscure in nature, but manifest to us, towards the things which

are really in nature more clear and certain.] The things which are

first obvious and apparent to us are complex; and from these we obtain,

by analysis, principles and elements. We must proceed from universals

to particulars. For the whole is better known to our senses than the

parts, and for the same reason, the universal better known than the

particular. And thus words signify things in a large and indiscriminate

way, which is afterwards analysed by definition; as we see that the

children at first call all men _father_, and all women _mother_, but

afterwards learn to distinguish."

There are various assertions contained in this extract which came to

be considered as standard maxims, and which occur constantly in the

writers of the middle ages. Such are, for instance, the maxim, "Verè

scire est per causas scire;" the remark, that compounds are known

to us before their parts, and the illustration from the expressions

used by children. Of the mode in which this subject was treated by

the schoolmen, we may judge by looking at passages of Thomas Aquinas

which treat of the subject of the human understanding. In the _Summa

Theologiæ_, the eighty-fifth Question is _On the manner and order of

understanding_, which subject he considers in eight Articles; and

these must, even now, be looked upon as exhibiting many of the most

important and interesting points of the subject. They are, _First_,

Whether our understanding understands by abstracting ideas (_species_)

from appearances; _Second_, Whether intelligible species abstracted

from appearances are related to our understanding as that _which_ we

understand, or that _by which_ we understand; _Third_, Whether our

understanding does naturally understand universals first; _Fourth_,

Whether our understanding can understand many things at once; _Fifth_,

Whether our understanding understands by compounding and dividing;

_Sixth_, Whether the understanding can err; _Seventh_, Whether one

person can understand the same thing better than another; _Eighth_,

Whether our understanding understands the indivisible sooner than

the divisible. And in the discussion of the last point, for example,

reference is made to the passage of Aristotle which we have already

quoted. "It may seem," he says, "that we understand the indivisible

before the divisible; for _the Philosopher_ says that we understand

and know by knowing principles and elements; but indivisibles are the

principles and elements of divisible things. But to this we may reply,

that in our receiving of science, principles and elements are not

always first; for sometimes from the sensible effects we go on to the

knowledge of intelligible principles and causes." We see that both the

objection and the answer are drawn from Aristotle.

We find the same close imitation of Aristotle in Albertus Magnus, who,

like Aquinas, flourished in the thirteenth century. Albertus, indeed,

wrote treatises corresponding to almost all those of the Stagirite, and

was called the _Ape of Aristotle_. In the beginning of his _Physics_,

he says, "Knowledge does not always begin from that which is first

according to the nature of things, but from that of which the knowledge

is easiest. For the human intellect, on account of its relation to the

senses (_propter reflexionem quam habet ad sensum_), collects science

from the senses; and thus it is easier for our knowledge to begin from

that which we can apprehend by sense, imagination, and intellect, than

from that which we apprehend by intellect alone." We see that he has

somewhat systematized what he has borrowed.

This disposition to dwell upon and systematize the leading doctrines

of metaphysics assumed a more definite and permanent shape in the

opposition of the Realists and Nominalists. The opposition involved

in this controversy is, in fact, that fundamental antithesis of Sense

and Ideas about which philosophy has always been engaged; and of

which we have marked the manifestation in Plato and Aristotle. The

question, What is the object of our thoughts when we reason concerning

the external world? must occur to all speculative minds: and the

difficulties of the answer are manifest. We must reply, either that our

own Ideas, or that Sensible Things, are the elements of our knowledge

of nature. And then the scruples again occur,--how we have any

_general_ knowledge if our thoughts are fixed on particular objects;

and, on the other hand,--how we can attain to any _true_ knowledge of

nature by contemplating ideas which are not identical with objects in

nature. The two opposite opinions maintained on this subject were, on

the one side,--that our general propositions refer to objects which

are _real_, though divested of the peculiarities of individuals; and,

on the other side,--that in such propositions, individuals are not

represented by any reality, but bound together by a _name_. These two

views were held by the Realists and Nominalists respectively: and thus

the Realist manifested the adherence to Ideas, and the Nominalist the

adherence to the impressions of Sense, which have always existed as

opposite yet correlative tendencies in man.

The Realists were the prevailing sect in the Scholastic times: for

example, both Thomas Aquinas and Duns Scotus, the _Angelical_ and the

_Subtle_ Doctor, held this opinion, although opposed to each other

in many of their leading doctrines on other subjects. And as the

Nominalist, fixing his attention upon sensible objects, is obliged to

consider what is the _principle of generalization_, in order that the

possibility of any general proposition may be conceivable; so on the

other hand, the Realist, beginning with the contemplation of universal

ideas, is compelled to ask what is the _principle of individuation_, in

order that he may comprehend the application of general propositions

in each particular instance. This inquiry concerning the principle of

individuation was accordingly a problem which occupied all the leading

minds among the Schoolmen[48]. It will be apparent from what has

been said, that it is only one of the many forms of the fundamental

antithesis of the Ideas and the Senses, which we have constantly before

us in this review.

The recognition of the derivation of our knowledge, in part at least,

from Experience, though always loose and incomplete, appears often

to be independent of the Peripatetic traditions. Thus Richard of St.

Victor, a writer of contemplative theology in the twelfth century,

says[49], that "there are three sources of knowledge, experience,

reason, faith. Some things we prove by experiment, others we collect

by reasoning, the certainty of others we hold by believing. And

with regard to temporal matters, we obtain our knowledge by actual

experience; the other guides belong to divine knowledge." Richard

also propounds a division of human knowledge which is clearly not

derived directly from the ancients, and which shows that considerable

attention must have been paid to such speculations. He begins by laying

down clearly and broadly the distinction, which, as we have seen, is

of primary importance, between _practice_ and _theory_. _Practice_,

he says, includes seven mechanical arts; those of the clothier, the

armourer, the navigator, the hunter, the physician, and the player.

_Theory_ is threefold, divine, natural, doctrinal; and is thus divided

into Theology, Physics, and Mathematics. _Mathematics_, he adds,

treats of the invisible _forms_ of visible things. We have seen that

by many profound thinkers this word _forms_ has been selected as best

fitted to describe those relations of things which are the subject of

mathematics. Again, Physics discovers causes from their effects and

effects from their causes. It would not be easy at the present day to

give a better account of the object of physical science. But Richard

of St. Victor makes this account still more remarkably judicious, by

the examples to which he alludes; which are earthquakes, the tides,

the virtues of plants, the instincts of animals, the classification of

minerals, plants and reptiles.

Unde tremor terris, quâ vi maria alta tumescant,

Herbarum vires, animos irasque ferarum,

Omne genus fruticum, lapidum quoque, reptiliumque.

He further adds[50], "Physical science ascends from effects to

causes, and descends again from causes to effects." This declaration

Francis Bacon himself might have adopted. It is true, that Richard

would probably have been little able to produce any clear and

definite instances of knowledge, in which this ascent and descent

were exemplified; but still the statement, even considered as a

mere conjectural thought, contains a portion of that sagacity and

comprehensive power which we admire so much in Bacon.

Richard of St. Victor, who lived in the twelfth century, thus exhibits

more vigour and independence of speculative power than Thomas Aquinas,

Albertus Magnus, and Duns Scotus, in the thirteenth. In the interval,

about the end of the twelfth century, the writings of Aristotle had

become generally known in the West; and had been elevated into the

standard of philosophical doctrine, by the divines mentioned above, who

felt a reverent sympathy with the systematizing and subtle spirit of

the Stagirite as soon as it was made manifest to them. These doctors,

following the example of their great forerunner, reduced every part

of human knowledge to a systematic form; the systems which they thus

framed were presented to men's minds as the only true philosophy, and

dissent from them was no longer considered to be blameless. It was an

offence against religion as well as reason to reject the truth, and

the truth could be but one. In this manner arose that claim which the

Doctors of the Church put forth to control men's opinions upon all

subjects, and which we have spoken of in the _History of Science_ as

the Dogmatism of the Middle Ages. There is no difficulty in giving

examples of this characteristic. We may take for instance a Statute of

the University of Paris, occasioned by a Bull of Pope John XXI., in

which it is enacted, "that no Master or Bachelor of any faculty, shall

presume to read lectures upon any author in a private room, on account

of the many perils which may arise therefrom; but shall read in public

places, where all may resort, and may faithfully report what is there

taught; excepting only books of Grammar and Logic, in which there can

be no presumption." And certain errors of Brescian are condemned in a

Rescript[51] of the papal Legate Odo, with the following expressions:

"Whereas, as we have been informed, certain Logical professors

treating of Theology in their disputations, and Theologians treating

of Logic, contrary to the command of the law are not afraid to mix and

confound the lots of the Lord's heritage; we exhort and admonish your

University, all and singular, that they be content with the landmarks

of the Sciences and Faculties which our Fathers have fixed; and that

having due fear of the curse pronounced in the law against him who

removeth his neighbour's landmark, you hold such sober wisdom according

to the Apostles, that ye may by no means incur the blame of innovation

or presumption."

The account which, in the _History of Science_, I gave of Dogmatism as

a characteristic of the middle ages, has been indignantly rejected by

a very pleasing modern writer, who has, with great feeling and great

diligence, brought into view the merits and beauties of those times,

termed by him _Ages of Faith_. He urges[52] that religious authority

was never claimed for physical science: and he quotes from Thomas

Aquinas, a passage in which the author protests against the practice

of confounding opinions of philosophy with doctrines of faith. We

might quote in return the Rescript[53] of Stephen, bishop of Paris,

in which he declares that there can be but one truth, and rejects

the distinction of things being true according to philosophy and not

according to the Catholic faith; and it might be added, that among the

errors condemned in this document are some of Thomas Aquinas himself.

We might further observe, that if no physical doctrines were condemned

in the times of which we now speak, this was because, on such subjects,

no new opinions were promulgated, and not because opinion was free.

As soon as new opinions, even on physical subjects, attracted general

notice, they were prohibited by authority, as we see in the case of

Galileo[54].

But this disinclination to recognize philosophy as independent of

religion, and this disposition to find in new theories, even in

physical ones, something contrary to religion or scripture, are, it

would seem, very natural tendencies of theologians; and it would be

unjust to assert that these propensities were confined to the periods

when the authority of papal Rome was highest; or that the spirit which

has in a great degree controlled and removed such habits was introduced

by the Reformation of religion in the sixteenth century. We must trace

to other causes, the clear and general recognition of Philosophy,

as distinct from Theology, and independent of her authority. In

the earlier ages of the Church, indeed, this separation had been

acknowledged. St. Augustin says, "A Christian should beware how he

speaks on questions of natural philosophy, as if they were doctrines of

Holy Scripture; for an infidel who should hear him deliver absurdities

could not avoid laughing. Thus the Christian would be confused, and the

infidel but little edified; for the infidel would conclude that our

authors really entertained these extravagant opinions, and therefore

they would despise them, to their own eternal ruin. Therefore the

opinions of philosophers should never be proposed as dogmas of faith,

or rejected as contrary to faith, when it is not certain that they are

so." These words are quoted with approbation by Thomas Aquinas, and

it is said[55], are cited in the same manner in every encyclopedical

work of the middle ages. This warning of genuine wisdom was afterwards

rejected, as we have seen; and it is only in modern times that its

value has again been fully recognized. And this improvement we must

ascribe, mainly, to the progress of physical science. For a great body

of undeniable truths on physical subjects being accumulated, such as

had no reference to nor connexion with the truths of religion, and

yet such as possessed a strong interest for most men's minds, it was

impossible longer to deny that there were wide provinces of knowledge

which were not included in the dominions of Theology, and over which

she had no authority. In the fifteenth and sixteenth centuries, the

fundamental doctrines of mechanics, hydrostatics, optics, magnetics,

chemistry, were established and promulgated; and along with them,

a vast train of consequences, attractive to the mind by the ideal

relations which they exhibited, and striking to the senses by the power

which they gave man over nature. Here was a region in which philosophy

felt herself entitled and impelled to assert her independence. From

this region, there is a gradation of subjects in which philosophy

advances more and more towards the peculiar domain of religion;

and at some intermediate points there have been, and probably will

always be, conflicts respecting the boundary line of the two fields

of speculation. For the limit is vague and obscure, and appears to

fluctuate and shift with the progress of time and knowledge.

Our business at present is not with the whole extent and limits

of philosophy, but with the progress of physical science more

particularly, and the methods by which it may be attained: and we are

endeavouring to trace historically the views which have prevailed

respecting such methods, at various periods of man's intellectual

progress. Among the most conspicuous of the revolutions which opinions

on this subject have undergone, is the transition from an implicit

trust in the internal powers of man's mind to a professed dependence

upon external observation; and from an unbounded reverence for the

wisdom of the past, to a fervid expectation of change and improvement.

The origin and progress of this disposition of mind;--the introduction

of a state of things in which men not only obtained a body of

indestructible truths from experience, and increased it from generation

to generation, but professedly, and we may say, ostentatiously,

declared such to be the source of their knowledge, and such their

hopes of its destined career;--the rise, in short, of Experimental

Philosophy, not only as a habit, but as a Philosophy of Experience, is

what we must now endeavour to exhibit.

FOOTNOTES:

[Footnote 48: See the opinion of Aquinas, in Degerando, _Hist. Com. des

Syst._ iv. 499; of Duns Scotus, _ibid._ iv. 523.]

[Footnote 49: _Liber Excerptionum_, Lib. i. c. i.]

[Footnote 50: _Tr. Ex._ Lib. i. c. vii.]

[Footnote 51: Tenneman, viii. 461.]

[Footnote 52: _Mores Catholici, or Ages of Faith_, viii. p. 247.]

[Footnote 53: Tenneman, viii. 460.]

[Footnote 54: If there were any doubt on this subject, we might

refer to the writers who afterwards questioned the supremacy of

Aristotle, and who with one voice assert that an infallible authority

had been claimed for him. Thus Laurentius Valla: "Quo minus ferendi

sunt recentes Peripatetici, qui nullius sectæ hominibus interdicunt

libertate ab Aristotele dissentiendi, quasi sophos hic, non

philosophus." _Pref. in Dial._ (Tenneman, ix. 29.) So Ludovicus Vives:

"Sunt ex philosophis et ex theologis qui non solum quo Aristoteles

pervenit extremum esse aiunt naturæ, sed quâ pervenit eam rectissimam

esse omnium et certissimam in natura viam." (Tenneman, ix. 43.) We

might urge too, the evasions practised by philosophical Reformers,

through fear of the dogmatism to which they had to submit; for example,

the protestation of Telesius at the end of the Proem to his work, _De

Rerum Natura_: "Nec tamen, si quid eorum quæ nobis posita sunt, sacris

literis, Catholicæve ecclesiæ decretis non cohæreat, tenendum id, quin

penitus rejiciendum asseveramus contendimusque. Neque enim _humana_

modo _ratio_ quævis, sed _ipse_ etiam _sensus_ illis _posthabendus_, et

si illis non congruat, abnegandus omnino et ipse etiam est sensus."]

[Footnote 55: _Ages of Faith_, viii. 247: to the author of which I am

obliged for this quotation.]

CHAPTER X.

THE INNOVATORS OF THE MIDDLE AGES.

_Raymond Lully._

1. _General Remarks._--In the rise of Experimental Philosophy,

understanding the term in the way just now stated, two features have

already been alluded to: the disposition to cast off the prevalent

reverence for the opinions and methods of preceding teachers with an

eager expectation of some vast advantage to be derived from a change;

and the belief that this improvement must be sought by drawing our

knowledge from external observation rather than from mere intellectual

efforts;--_the Insurrection against Authority_, and _the Appeal to

Experience_. These two movements were closely connected; but they may

easily be distinguished, and in fact, persons were very prominent in

the former part of the task, who had no comprehension of the latter

principle, from which alone the change derives its value. There were

many Malcontents who had not the temper, talent or knowledge, which

fitted them to be Reformers.

The authority which was questioned, in the struggle of which we speak,

was that of the Scholastic System, the combination of Philosophy with

Theology; of which Aristotle, presented in the form and manner which

the Doctors of the Church had imposed upon him, is to be considered

the representative. When there was demanded of men a submission of

the mind, such as this system claimed, the natural love of freedom in

man's bosom, and the speculative tendencies of his intellect, rose in

rebellion, from time to time, against the ruling oppression. We find

in all periods of the scholastic ages examples of this disposition

of man to resist overstrained authority; the tendency being mostly,

however, combined with a want of solid thought, and showing itself

in extravagant pretensions and fantastical systems put forwards by

the insurgents. We have pointed out one such opponent[56] of the

established systems, even among the Arabian schoolmen, a more servile

race than ever the Europeans were. We may here notice more especially

an extraordinary character who appeared in the thirteenth century, and

who may be considered as belonging to the Prelude of the Reform in

Philosophy, although he had no share in the Reform itself.

2. _Raymond Lully._--Raymond Lully is perhaps traditionally best known

as an Alchemist, of which art he appears to have been a cultivator. But

this was only one of the many impulses of a spirit ardently thirsty

of knowledge and novelty. He had[57], in his youth, been a man of

pleasure, but was driven by a sudden shock of feeling to resolve on a

complete change of life. He plunged into solitude, endeavoured to still

the remorse of his conscience by prayer and penance, and soon had his

soul possessed by visions which he conceived were vouchsafed to him.

In the feeling of religious enthusiasm thus excited, he resolved to

devote his life to the diffusion of Christian truth among Heathens and

Mahomedans. For this purpose, at the age of thirty he betook himself

to the study of Grammar, and of the Arabic language. He breathed

earnest supplications for an illumination from above; and these were

answered by his receiving from heaven, as his admirers declare, his

_Ars Magna_ by which he was able without labour or effort to learn

and apply all knowledge. The real state of the case is, that he put

himself in opposition to the established systems, and propounded a New

Art, from which he promised the most wonderful results; but that his

Art really is merely a mode of combining ideal conceptions without any

reference to real sources of knowledge, or any possibility of real

advantage. In a Treatise addressed, in A.D. 1310, to King Philip of

France, entitled _Liber Lamentationis Duodecim Principiorum Philosophiæ

contra Averroistas_, Lully introduced Philosophy, accompanied by her

twelve Principles, (Matter, Form, Generation, &c.) uttering loud

complaints against the prevailing system of doctrine; and represents

her as presenting to the king a petition that she may be upheld and

restored by her favourite, the Author. His _Tabula Generalis ad omnes

Scientias applicabilis_ was begun the 15th September, 1292, in the

Harbour of Tunis, and finished in 1293, at Naples. In order to frame an

Art of thus tabulating all existing sciences, and indeed all possible

knowledge, he divides into various classes the conceptions with which

he has to deal. The first class contains nine _Absolute Conceptions_:

Goodness, Greatness, Duration, Power, Wisdom, Will, Virtue, Truth,

Majesty. The second class has nine _Relative Conceptions_: Difference,

Identity, Contrariety, Beginning, Middle, End, Majority, Equality,

Minority. The third class contains nine _Questions_: Whether? What?

Whence? Why? How great? How circumstanced? When? Where? and How?

The fourth class contains the nine _Most General Subjects_: God,

Angel, Heaven, Man, _Imaginativum_, _Sensitivum_, _Vegetativum_,

_Elementativum_, _Instrumentativum_. Then come nine _Prædicaments_,

nine _Moral Qualities_, and so on. These conceptions are arranged in

the compartments of certain concentric moveable circles, and give

various combinations by means of triangles and other figures, and thus

propositions are constructed.

It must be clear at once, that real knowledge, which is the union of

facts and ideas, can never result from this machinery for shifting

about, joining and disjoining, empty conceptions. This, and all similar

schemes, go upon the supposition that the logical combinations of

notions do of themselves compose knowledge; and that really existing

things may be arrived at by a successive system of derivation from

our most general ideas. It is imagined that by distributing the

nomenclature of abstract ideas according to the place which they can

hold in our propositions, and by combining them according to certain

conditions, we may obtain formulæ including all possible truths, and

thus fabricate a science in which all sciences are contained. We thus

obtain the means of talking and writing upon all subjects, without the

trouble of thinking: the revolutions of the emblematical figures are

substituted for the operations of the mind. Both exertion of thought,

and knowledge of facts, become superfluous. And this reflection, adds

an intelligent author[58], explains the enormous number of books which

Lully is said to have written; for he might have written those even

during his sleep, by the aid of a moving power which should keep his

machine in motion. Having once devised this invention for manufacturing

science, Lully varied it in a thousand ways, and followed it into

a variety of developments. Besides Synoptical Tables, he employs

Genealogical Trees, each of which he dignifies with the name of the

Tree of Science. The only requisite for the application of his System

was a certain agreement in the numbers of the classes into which

different subjects were distributed; and as this symmetry does not

really exist in the operations of our thoughts, some violence was done

to the natural distinction and subordination of conceptions, in order

to fit them for the use of the system.

Thus Lully, while he professed to teach an Art which was to shed new

light upon every part of science, was in fact employed in a pedantic

and trifling repetition of known truths or truisms; and while he

complained of the errors of existing methods, he proposed in their

place one which was far more empty, barren, and worthless, than the

customary processes of human thought. Yet his method is spoken of[59]

with some praise by Leibnitz, who indeed rather delighted in the

region of ideas and words, than in the world of realities. But Francis

Bacon speaks far otherwise and more justly on this subject[60]. "It is

not to be omitted that some men, swollen with emptiness rather than

knowledge, have laboured to produce a certain Method, not deserving

the name of a legitimate Method, since it is rather a method of

imposture: which yet is doubtless highly grateful to certain would-be

philosophers. This method scatters about certain little drops of

science in such a manner that a smatterer may make a perverse and

ostentatious use of them with a certain show of learning. Such was

the art of Lully, which consisted of nothing but a mass and heap of

the words of each science; with the intention that he who can readily

produce the words of any science shall be supposed to know the science

itself. Such collections are like a rag shop, where you find a patch of

everything, but nothing which is of any value."

FOOTNOTES:

[Footnote 56: Algazel. See _Hist. Ind. Sc._ b. iv. c. i.]

[Footnote 57: Tenneman, viii. 830.]

[Footnote 58: Degerando, iv. 535.]

[Footnote 59: Leibnitz's expressions are, (_Op._ t. vi. p. 16): "Quand

j'étais jeune, je prenois quelque a l'_Art_ de Lulle, mais je crus y

entrevoir bien des défectuosités, dont j'ai dit quelque chose dans un

petit Essai d'écolier intitulé _De Arte Combinatoria_, publié en 1666,

et qui a été réimprimé après malgré moi. Mais comme je ne méprise

rien facilement, excepté les arts divinatoires que ne sont que des

tromperies toutes pures, j'ai trouvé quelque chose d'estimable encore

dans l'_Art_ de Lulle."]

[Footnote 60: _Works_, vii. 296.]

CHAPTER XI.

THE INNOVATORS OF THE MIDDLE AGES--CONTINUED.

_Roger Bacon._

We now come to a philosopher of a very different character, who was

impelled to declare his dissent from the reigning philosophy by the

abundance of his knowledge, and by his clear apprehension of the mode

in which real knowledge had been acquired and must be increased.

Roger Bacon was born in 1214, near Ilchester, in Somersetshire, of

an old family. In his youth he was a student at Oxford, and made

extraordinary progress in all branches of learning. He then went to

the University of Paris, as was at that time the custom of learned

Englishmen, and there received the degree of Doctor of Theology. At

the persuasion of Robert Grostête, bishop of Lincoln, he entered the

brotherhood of Franciscans in Oxford, and gave himself up to study

with extraordinary fervour. He was termed by his brother monks _Doctor

Mirabilis_. We know from his own works, as well as from the traditions

concerning him, that he possessed an intimate acquaintance with all the

science of his time which could be acquired from books; and that he had

made many remarkable advances by means of his own experimental labours.

He was acquainted with Arabic, as well as with the other languages

common in his time. In the title of his works, we find the whole

range of science and philosophy, Mathematics and Mechanics, Optics,

Astronomy, Geography, Chronology, Chemistry, Magic, Music, Medicine,

Grammar, Logic, Metaphysics, Ethics, and Theology; and judging from

those which are published, these works are full of sound and exact

knowledge. He is, with good reason, supposed to have discovered, or to

have had some knowledge of, several of the most remarkable inventions

which were made generally known soon afterwards; as gunpowder, lenses,

burning specula, telescopes, clocks, the correction of the calendar,

and the explanation of the rainbow.

Thus possessing, in the acquirements and habits of his own mind,

abundant examples of the nature of knowledge and of the process of

invention, Roger Bacon felt also a deep interest in the growth and

progress of science, a spirit of inquiry respecting the causes which

produced or prevented its advance, and a fervent hope and trust in its

future destinies; and these feelings impelled him to speculate worthily

and wisely respecting a Reform of the Method of Philosophizing. The

manuscripts of his works have existed for nearly six hundred years in

many of the libraries of Europe, and especially in those of England;

and for a long period the very imperfect portions of them which were

generally known, left the character and attainments of the author

shrouded in a kind of mysterious obscurity. About a century ago,

however, his _Opus Majus_ was published[61] by Dr. S. Jebb, principally

from a manuscript in the Library of Trinity College, Dublin; and this

contained most or all of the separate works which were previously

known to the public, along with others still more peculiar and

characteristic. We are thus able to judge of Roger Bacon's knowledge

and of his views, and they are in every way well worthy our attention.

The _Opus Majus_ is addressed to Pope Clement the Fourth, whom Bacon

had known when he was legate in England as Cardinal-bishop of Sabina,

and who admired the talents of the monk, and pitied him for the

persecutions to which he was exposed. On his elevation to the papal

chair, this account of Bacon's labours and views was sent, at the

earnest request of the pontiff. Besides the _Opus Majus_, he wrote

two others, the _Opus Minus_ and _Opus Tertium_; which were also sent

to the pope, as the author says[62], "on account of the danger of

roads, and the possible loss of the work." These works still exist

unpublished, in the Cottonian and other libraries. The _Opus Majus_ is

a work equally wonderful with regard to its general scheme, and to the

special treatises with which the outlines of the plan are filled up.

The professed object of the work is to urge the necessity of a reform

in the mode of philosophizing, to set forth the reasons why knowledge

had not made a greater progress, to draw back attention to the sources

of knowledge which had been unwisely neglected, to discover other

sources which were yet almost untouched, and to animate men in the

undertaking, by a prospect of the vast advantages which it offered.

In the development of this plan, all the leading portions of science

are expounded in the most complete shape which they had at that time

assumed; and improvements of a very wide and striking kind are proposed

in some of the principal of these departments. Even if the work had had

no leading purpose, it would have been highly valuable as a treasure of

the most solid knowledge and soundest speculations of the time; even

if it had contained no such details, it would have been a work most

remarkable for its general views and scope. It may be considered as,

at the same time, the _Encyclopedia_ and the _Novum Organon_ of the

thirteenth century.

Since this work is thus so important in the history of Inductive

Philosophy I shall give, in a note, a view[63] of its divisions and

contents. But I must now endeavour to point out more especially the way

in which the various principles, which the reform of scientific method

involved, are here brought into view.

One of the first points to be noticed for this purpose, is the

resistance to authority; and at the stage of philosophical history

with which we here have to do, this means resistance to the authority

of Aristotle, as adopted and interpreted by the Doctors of the

Schools. Bacon's work[64] is divided into Six Parts; and of these

Parts, the First is, Of the four universal Causes of all Human

Ignorance. The causes thus enumerated[65] are:--the force of unworthy

authority;--traditionary habit;--the imperfection of the undisciplined

senses;--and the disposition to conceal our ignorance and to make an

ostentatious show of our knowledge. These influences involve every man,

occupy every condition. They prevent our obtaining the most useful and

large and fair doctrines of wisdom, the secret of all sciences and

arts. He then proceeds to argue, from the testimony of philosophers

themselves, that the authority of antiquity, and especially of

Aristotle, is not infallible. "We find[66] their books full of doubts,

obscurities, and perplexities. They scarce agree with each other in

one empty question or one worthless sophism, or one operation of

science, as one man agrees with another in the practical operations

of medicine, surgery, and the like arts of Secular men. Indeed," he

adds, "not only the philosophers, but the saints have fallen into

errors which they have afterwards retracted," and this he instances

in Augustin, Jerome, and others. He gives an admirable sketch[67] of

the progress of philosophy from the Ionic School to Aristotle; of whom

he speaks with great applause. "Yet," he adds[68], "those who came

after him corrected him in some things, and added many things to his

works, and shall go on adding to the end of the world." Aristotle, he

adds, is now called peculiarly[69] the Philosopher, "yet there was a

time when his philosophy was silent and unregarded, either on account

of the rarity of copies of his works, or their difficulty, or from

envy; till after the time of Mahomet, when Avicenna and Averroes, and

others, recalled this philosophy into the full light of exposition. And

although the Logic and some other works were translated by Boethius

from the Greek, yet the philosophy of Aristotle first received a quick

increase among the Latins at the time of Michael Scot; who, in the year

of our Lord 1230, appeared, bringing with him portions of the books of

Aristotle on Natural Philosophy and Mathematics. And yet a small part

only of the works of this author is translated, and a still smaller

part is in the hands of common students." He adds further[70] (in the

Third Part of the _Opus Majus_, which is a Dissertation on language),

that the translations which are current of these writings, are very

bad and imperfect. With these views, he is moved to express himself

somewhat impatiently[71] respecting these works: "If I had," he says,

"power over the works of Aristotle, I would have them all burnt; for

it is only a loss of time to study in them, and a cause of error, and

a multiplication of ignorance beyond expression." "The common herd of

students," he says, "with their heads, have no principle by which they

can be excited to any worthy employment; and hence they mope and make

asses of themselves over their bad translations, and lose their time,

and trouble, and money."

The remedies which he recommends for these evils, are, in the first

place, the study of that only perfect wisdom which is to be found in

the sacred Scripture[72], in the next place, the study of mathematics

and the use of experiment[73]. By the aid of these methods, Bacon

anticipates the most splendid progress for human knowledge. He takes up

the strain of hope and confidence which we have noticed as so peculiar

in the Roman writers; and quotes some of the passages of Seneca which

we adduced in illustration of this:--that the attempts in science were

at first rude and imperfect, and were afterwards improved;--that the

day will come, when what is still unknown shall be brought to light by

the progress of time and the labours of a longer period;--that one age

does not suffice for inquiries so wide and various;--that the people

of future times shall know many things unknown to us;--and that the

time shall arrive when posterity will wonder that we overlooked what

was so obvious. Bacon himself adds anticipations more peculiarly in

the spirit of his own time. "We have seen," he says, at the end of the

work, "how Aristotle, by the ways which wisdom teaches, could give to

Alexander the empire of the world. And this the Church ought to take

into consideration against the infidels and rebels, that there may be a

sparing of Christian blood, and especially on account of the troubles

that shall come to pass in the days of Antichrist; which by the grace

of God, it would be easy to obviate, if prelates and princes would

encourage study, and join in searching out the secrets of nature and

art."

It may not be improper to observe here that this belief in the

appointed progress of knowledge, is not combined with any overweening

belief in the unbounded and independent power of the human intellect.

On the contrary, one of the lessons which Bacon draws from the state

and prospects of knowledge, is the duty of faith and humility. "To

him," he says[74], "who denies the truth of the faith because he is

unable to understand it, I will propose in reply the course of nature,

and as we have seen it in examples." And after giving some instances,

he adds, "These, and the like, ought to move men and to excite them

to the reception of divine truths. For if, in the vilest objects of

creation, truths are found, before which the inward pride of man must

bow, and believe though it cannot understand, how much more should

man humble his mind before the glorious truths of God!" He had before

said[75]: "Man is incapable of perfect wisdom in this life; it is

hard for him to ascend towards perfection, easy to glide downwards

to falsehoods and vanities: let him then not boast of his wisdom, or

extol his knowledge. What he knows is little and worthless, in respect

of that which he believes without knowing; and still less, in respect

of that which he is ignorant of. He is mad who thinks highly of his

wisdom; he most mad, who exhibits it as something to be wondered at."

He adds, as another reason for humility, that he has proved by trial,

he could teach in one year, to a poor boy, the marrow of all that

the most diligent person could acquire in forty years' laborious and

expensive study.

To proceed somewhat more in detail with regard to Roger Bacon's views

of a Reform in Scientific Inquiry, we may observe that by making

Mathematics and Experiment the two great points of his recommendation,

he directed his improvement to the two essential parts of all

knowledge, Ideas and Facts, and thus took the course which the most

enlightened philosophy would have suggested. He did not urge the

prosecution of experiment, to the comparative neglect of the existing

mathematical sciences and conception; a fault which there is some

ground for ascribing to his great namesake and successor Francis

Bacon: still less did he content himself with a mere protest against

the authority of the schools, and a vague demand for change, which

was almost all that was done by those who put themselves forward as

reformers in the intermediate time. Roger Bacon holds his way steadily

between the two poles of human knowledge; which, as we have seen, it

is far from easy to do. "There are two modes of knowing," says he[76];

"by argument, and by experiment. Argument concludes a question; but

it does not make us feel certain, or acquiesce in the contemplation

of truth, except the truth be also found to be so by experience."

It is not easy to express more decidedly the clearly seen union of

exact conceptions with certain facts, which, as we have explained,

constitutes real knowledge.

One large division of the _Opus Majus_ is "On the Usefulness of

Mathematics," which is shown by a copious enumeration of existing

branches of knowledge, as Chronology, Geography, the Calendar and

(in a separate Part) Optics. There is a chapter[77], in which it is

proved by reason, that all science requires mathematics. And the

arguments which are used to establish this doctrine, show a most just

appreciation of the office of mathematics in science. They are such as

follows:--That other sciences use examples taken from mathematics as

the most evident:--That mathematical knowledge is, as it were, innate

in us, on which point he refers to the well-known dialogue of Plato,

as quoted by Cicero:--That this science, being the easiest, offers the

best introduction to the more difficult:--That in mathematics, things

as known to us are identical with things as known to nature:--That

we can here entirely avoid doubt and error, and obtain certainty and

truth:--That mathematics is prior to other sciences in nature, because

it takes cognizance of quantity, which is apprehended by intuition,

(_intuitu intellectus_). "Moreover," he adds[78], "there have been

found famous men, as Robert, bishop of Lincoln, and Brother Adam

Marshman (de Marisco), and many others, who by the power of mathematics

have been able to explain the causes of things; as may be seen in the

writings of these men, for instance, concerning the Rainbow and Comets,

and the generation of heat, and climates, and the celestial bodies."

But undoubtedly the most remarkable portion of the _Opus Majus_ is the

Sixth and last Part, which is entitled "De Scientia experimentali."

It is indeed an extraordinary circumstance to find a writer of the

thirteenth century, not only recognizing experiment as one source

of knowledge, but urging its claims as something far more important

than men had yet been aware of, exemplifying its value by striking

and just examples, and speaking of its authority with a dignity of

diction which sounds like a foremurmur of the Baconian sentences

uttered nearly four hundred years later. Yet this is the character of

what we here find[79]. "Experimental science, the sole mistress of

speculative sciences, has three great Prerogatives among other parts

of knowledge: First she tests by experiment the noblest conclusions of

all other sciences: Next she discovers respecting the notions which

other sciences deal with, magnificent truths to which these sciences of

themselves can by no means attain: her Third dignity is, that she by

her own power and without respect of other sciences, investigates the

secret of nature."

The examples which Bacon gives of these "Prerogatives" are very

curious, exhibiting, among some error and credulity, sound and clear

views. His leading example of the First Prerogative, is the Rainbow,

of which the cause, as given by Aristotle, is tested by reference to

experiment with a skill which is, even to us now, truly admirable.

The examples of the Second Prerogative are three:--_first_, the art

of making an artificial sphere which shall move with the heavens by

natural influences, which Bacon trusts may be done, though astronomy

herself cannot do it--"et tunc," he says, "thesaurum unius regis

valeret hoc instrumentum;"--_secondly_, the art of prolonging life,

which experiment may teach, though medicine has no means of securing

it except by regimen[80];--_thirdly_, the art of making gold finer

than fine gold, which goes beyond the power of alchemy. The Third

Prerogative of experimental science, arts independent of the received

sciences, is exemplified in many curious examples, many of them

whimsical traditions. Thus it is said that the character of a people

may be altered by altering the air[81]. Alexander, it seems, applied

to Aristotle to know whether he should exterminate certain nations

which he had discovered, as being irreclaimably barbarous; to which

the philosopher replied, "If you can alter their air, permit them to

live, if not, put them to death." In this part, we find the suggestion

that the fire-works made by children, of saltpetre, might lead to the

invention of a formidable military weapon.

It could not be expected that Roger Bacon, at a time when experimental

science hardly existed, could give any _precepts_ for the discovery

of truth by experiment. But nothing can be a better _example_ of the

method of such investigation, than his inquiry concerning the cause of

the Rainbow. Neither Aristotle, nor Avicenna, nor Seneca, he says, have

given us any clear knowledge of this matter, but experimental science

can do so. Let the experimenter (_experimentator_) consider the cases

in which he finds the same colours, as the hexagonal crystals from

Ireland and India; by looking into these he will see colours like those

of the rainbow. Many think that this arises from some special virtue of

these stones and their hexagonal figure; let therefore the experimenter

go on, and he will find the same in other transparent stones, in dark

ones as well as in light-coloured. He will find the same effect also

in other forms than the hexagon, if they be furrowed in the surface,

as the Irish crystals are. Let him consider too, that he sees the same

colours in the drops which are dashed from oars in the sunshine;--and

in the spray thrown by a millwheel;--and in the dew-drops which lie on

the grass in a meadow on a summer-morning;--and if a man takes water

in his mouth and projects it on one side into a sunbeam;--and if in an

oil-lamp hanging in the air, the rays fall in certain positions upon

the surface of the oil;--and in many other ways, are colours produced.

We have here a collection of instances, which are almost all examples

of the same kind as the phenomenon under consideration; and by the help

of a principle collected by induction from these facts, the colours of

the rainbow were afterwards really explained.

With regard to the form and other circumstances of the bow he is still

more precise. He bids us measure the height of the bow and of the sun,

to show that the center of the bow is exactly opposite to the sun.

He explains the circular form of the bow,--its being independent of

the form of the cloud, its moving when we move, its flying when we

follow,--by its consisting of the reflections from a vast number of

minute drops. He does not, indeed, trace the course of the rays through

the drop, or account for the precise magnitude which the bow assumes;

but he approaches to the verge of this part of the explanation; and

must be considered as having given a most happy example of experimental

inquiry into nature, at a time when such examples were exceedingly

scanty. In this respect, he was more fortunate than Francis Bacon, as

we shall hereafter see.

We know but little of the biography of Roger Bacon, but we have every

reason to believe that his influence upon his age was not great.

He was suspected of magic, and is said to have been put into close

confinement in consequence of this charge. In his work he speaks

of Astrology as a science well worth cultivating. "But," says he,

"Theologians and Decretists, not being learned in such matters and

seeing that evil as well as good may be done, neglect and abhor such

things, and reckon them among Magic Arts." We have already seen, that

at the very time when Bacon was thus raising his voice against the

habit of blindly following authority, and seeking for all science

in Aristotle, Thomas Aquinas was employed in fashioning Aristotle's

tenets into that fixed form in which they became the great impediment

to the progress of knowledge. It would seem, indeed, that something

of a struggle between the progressive and stationary powers of the

human mind was going on at this time. Bacon himself says[82], "Never

was there so great an appearance of wisdom, nor so much exercise of

study in so many Faculties, in so many regions, as for this last forty

years. Doctors are dispersed everywhere, in every castle, in every

burgh, and especially by the students of two Orders, (he means the

Franciscans and Dominicans, who were almost the only religious orders

that distinguished themselves by an application to study[83],) which

has not happened except for about forty years. And yet there was never

so much ignorance, so much error." And in the part of his work which

refers to Mathematics, he says of that study[84], that it is the door

and the key of the sciences; and that the neglect of it for thirty or

forty years has entirely ruined the studies of the Latins. According to

these statements, some change, disastrous to the fortunes of science,

must have taken place about 1230, soon after the foundation of the

Dominican and Franciscan Orders[85]. Nor can we doubt that the adoption

of the Aristotelian philosophy by these two Orders, in the form in

which the Angelical Doctor had systematized it, was one of the events

which most tended to defer, for three centuries, the reform which Roger

Bacon urged as a matter of crying necessity in his own time.

FOOTNOTES:

[Footnote 61: _Fratris Rogeri Bacon, Ordinis Minorum_, Opus Majus, _ad

Clementem Quartum, Pontificem Romanum, ex MS. Codice Dubliniensi cum

aliis quibusdam collato, nunc primum edidit_ S. Jebb, M.D. Londini,

1733.]

[Footnote 62: _Opus Majus_, Præf.]

[Footnote 63: Contents of Roger Bacon's _Opus Majus_.

Part I. On the four causes of human ignorance:--Authority, Custom,

Popular Opinion, and the Pride of supposed Knowledge.

Part II. On the source of perfect wisdom in the Sacred Scripture.

Part III. On the Usefulness of Grammar.

Part IV. On the Usefulness of Mathematics.

(1) The necessity of Mathematics in Human Things (published separately

as the _Specula Mathematica_).

(2) The necessity of Mathematics in Divine Things.--1°. This study

has occupied holy men: 2°. Geography: 3°. Chronology: 4°. Cycles;

the Golden Number, &c.: 5°. Natural Phenomena, as the Rainbow: 6°.

Arithmetic: 7°. Music.

(3) The necessity of Mathematics in Ecclesiastical Things.--1°. The

Certification of Faith: 2°. The Correction of the Calendar.

(4) The necessity of Mathematics in the State.--1°. Of Climates: 2°.

Hydrography: 3°. Geography: 4°. Astrology.

Part V. On Perspective (published separately as _Perspectiva_).

(1) The organs of vision.

(2) Vision in straight lines.

(3) Vision reflected and refracted.

(4) De multiplicatione specierum (on the propagation of the impressions

of light, heat, &c.)

Part VI. On Experimental Science.]

[Footnote 64: _Op. Maj._ p. 1.]

[Footnote 65: _Ibid._ p. 2.]

[Footnote 66: _Ibid._ p. 10.]

[Footnote 67: I will give a specimen. _Opus Majus_, c. viii. p. 35:

"These two kinds of philosophers, the Ionic and Italic, ramified

through many sects and various successors, till they came to the

doctrine of Aristotle, who corrected and changed the propositions

of all his predecessors, and attempted to perfect philosophy. In

the [Italic] succession, Pythagoras, Archytas Tarentinus and Timæus

are most prominently mentioned. But the principal philosophers, as

Socrates, Plato, and Aristotle, did not descend from this line, but

were Ionics and true Greeks, of whom the first was Thales Milesius....

Socrates, according to Augustine in his 8th book, is related to have

been a disciple of Archelaus. This Socrates is called the father of the

great philosophers, since he was the master of Plato and Aristotle,

from whom all the sects of philosophers descended.... Plato, first

learning what Socrates and Greece could teach, made a laborious voyage

to Egypt, to Archytas of Tarentum and Timæus, as says Jerome to

Paulinus. And this Plato is, according to holy men, preferred to all

philosophers, because he has written many excellent things concerning

God, and morality, and a future life, which agree with the divine

wisdom of God. And Aristotle was born before the death of Socrates,

since he was his hearer for three years, as we read in the life of

Aristotle.... This Aristotle, being made the master of Alexander the

Great, sent two thousand men into all regions of the earth, to search

out the nature of things, as Pliny relates in the 8th book of his

_Naturalia_, and composed a thousand books, as we read in his life."]

[Footnote 68: _Ibid._ p. 36.]

[Footnote 69: _Autonomaticè._]

[Footnote 70: _Op. Maj._ p. 46.]

[Footnote 71: See _Pref._ to Jebb's edition. The passages, there

quoted, however, are not extracts from the _Opus Majus_, but

(apparently) from the _Opus Minus_ (_MS. Cott._ Tib. c. 5.) "Si haberem

potestatem supra libros Aristotelis, ego facerem omnes cremari; quia

non est nisi temporis amissio studere in illis, et causa erroris, et

multiplicatio ignorantiæ ultra id quod valeat explicari.... Vulgus

studentum cum capitibus suis non habet unde excitetur ad aliquid

dignum, et ideo languet et _asininat_ circa male translata, et tempus

et studium amittit in omnibus et expensas."]

[Footnote 72: Part ii.]

[Footnote 73: Parts iv. v. and vi.]

[Footnote 74: _Op. Maj._ p. 476.]

[Footnote 75: _Op. Maj._ p. 15.]

[Footnote 76: _Ibid._ p. 445, see also p. 448. "Scientiæ aliæ sciunt

sua principia invenire per experimenta, sed conclusiones per argumenta

facta ex principiis inventis. Si vero debeant habere experientiam

conclusionum suarum particularem et completam, tunc oportet quod

habeant per adjutorium istius scientiæ nobilis (experimentalis)."]

[Footnote 77: _Op. Maj._ p. 60.]

[Footnote 78: _Ibid._ p. 64.]

[Footnote 79: "Veritates magnificas in terminis aliarum scientiarum in

quas per nullam viam possunt illæ scientiæ, hæc sola scientiarum domina

speculativarum, potest dare." _Op. Maj._ p. 465.]

[Footnote 80: One of the ingredients of a preparation here mentioned,

is the flesh of a dragon, which it appears is used as food by the

Ethiopians. The mode of preparing this food cannot fail to amuse the

reader. "Where there are good flying dragons, by the art which they

possess, they draw them out of their dens, and have bridles and saddles

in readiness, and they ride upon them, and make them bound about in the

air in a violent manner, that the hardness and toughness of the flesh

may be reduced, as boars are hunted and bulls are baited before they

are killed for eating." _Op. Maj._ p. 470.]

[Footnote 81: _Op. Maj._ p. 473.]

[Footnote 82: Quoted by Jebb, _Pref._ to _Op. Maj._]

[Footnote 83: Mosheim, _Hist._ iii. 161.]

[Footnote 84: _Op. Maj._ p. 57.]

[Footnote 85: Mosheim, iii. 161.]

CHAPTER XII.

THE REVIVAL OF PLATONISM.

1. _Causes of Delay in the Advance of Knowledge._--In the insight

possessed by learned men into the method by which truth was to be

discovered, the fourteenth and fifteenth centuries went backwards,

rather than forwards, from the point which had been reached in the

thirteenth. Roger Bacon had urged them to have recourse to experiment;

but they returned with additional and exclusive zeal to the more

favourite employment of reasoning upon their own conceptions. He had

called upon them to look at the world without; but their eyes forthwith

turned back upon the world within. In the constant oscillation of the

human mind between Ideas and Facts, after having for a moment touched

the latter, it seemed to swing back more impetuously to the former.

Not only was the philosophy of Aristotle firmly established for a

considerable period, but when men began to question its authority, they

attempted to set up in its place a philosophy still more purely ideal,

that of Plato. It was not till the actual progress of experimental

knowledge for some centuries had given it a vast accumulation of force,

that it was able to break its way fully into the circle of speculative

science. The new Platonist schoolmen had to run their course, the

practical discoverers had to prove their merit by their works, the

Italian innovators had to utter their aspirations for a change, before

the second Bacon could truly declare that the time for a fundamental

reform was at length arrived.

It cannot but seem strange, to any one who attempts to trace the

general outline of the intellectual progress of man, and who considers

him as under the guidance of a Providential sway, that he should

thus be permitted to wander so long in a wilderness of intellectual

darkness; and even to turn back, by a perverse caprice as it might

seem, when on the very border of the brighter and better land which was

his destined inheritance. We do not attempt to solve this difficulty:

but such a course of things naturally suggests the thought, that a

progress in physical science is not the main object of man's career,

in the eyes of the Power who directs the fortunes of our race. We

can easily conceive that it may have been necessary to man's general

welfare that he should continue to turn his eyes inwards upon his own

heart and faculties, till Law and Duty, Religion and Government, Faith

and Hope, had been fully incorporated with all the past acquisitions of

human intellect; rather than that he should have rushed on into a train

of discoveries tending to chain him to the objects and operations of

the material world. The systematic Law[86] and philosophical Theology

which acquired their ascendancy in men's minds at the time of which

we speak, kept them engaged in a region of speculations which perhaps

prepared the way for a profounder and wider civilization, for a more

elevated and spiritual character, than might have been possible without

such a preparation. The great Italian poet of the fourteenth century

speaks with strong admiration of the founders of the system which

prevailed in his time. Thomas, Albert, Gratian, Peter Lombard, occupy

distinguished places in the Paradise. The first, who is the poet's

instructor, says,--

Io fui degli agni della santa greggia

Che Domenico mena per cammino

U' ben s'impingua se non si vaneggia.

Questo che m'è a destra piu vicino

Frate e maestro fummi; ed esso Alberto

E di Cologna, ed io Tomas d'Aquino....

Quell' altro fiammeggiar esce del riso

De Grazian, che l'uno et l'altro foro

Ajutò si che piace in Paradiso.

I, then, was of the lambs that Dominic

Leads, for his saintly flock, along the way

Where well they thrive not swoln with vanity.

He nearest on my right-hand brother was

And master to me; Albert of Cologne

Is this; and of Aquinum Thomas, I....

That next resplendence issues from the smile

Of Gratian, who to either forum lent

Such help as favour wins in Paradise.

It appears probable that neither poetry, nor painting, nor the other

arts which require for their perfection a lofty and spiritualized

imagination, would have appeared in the noble and beautiful forms which

they assumed in the fourteenth and fifteenth century, if men of genius

had, at the beginning of that period, made it their main business

to discover the laws of nature, and to reduce them to a rigorous

scientific form. Yet who can doubt that the absence of these touching

and impressive works would have left one of the best and purest parts

of man's nature without its due nutriment and development? It may

perhaps be a necessary condition in the progress of man, that the Arts

which aim at beauty should reach their excellence before the Sciences

which seek speculative truth; and if this be so, we inherit, from the

middle ages, treasures which may well reconcile us to the delay which

took place in their cultivation of experimental science.

However this may be, it is our business at present to trace the

circumstances of this very lingering advance. We have already noticed

the contest of the Nominalists and Realists, which was one form,

though, with regard to scientific methods, an unprofitable one, of

the antithesis of Ideas and Things. Though, therefore, this struggle

continued, we need not dwell upon it. The Nominalists denied the real

existence of Ideas, which doctrine was to a great extent implied

in the prevailing systems; but the controversy in which they thus

engaged, did not lead them to seek for knowledge in a new field and

by new methods. The arguments which Occam the Nominalist opposes to

those of Duns Scotus the Realist, are marked with the stamp of the

same system, and consist only in permutations and combinations of the

same elementary conceptions. It was not till the impulse of external

circumstances was added to the discontent, which the more stirring

intellects felt towards the barren dogmatism of their age, that the

activity of the human mind was again called into full play, and a new

career of progression entered upon, till then undreamt of, except by a

few prophetic spirits.

2. _Causes of Progress._--These circumstances were principally the

revival of Greek and Roman literature, the invention of Printing, the

Protestant Reformation, and a great number of curious discoveries and

inventions in the arts, which were soon succeeded by important steps

in speculative physical science. Connected with the first of these

events, was the rise of a party of learned men who expressed their

dissatisfaction with the Aristotelian philosophy, as it was then

taught, and manifested a strong preference for the views of Plato. It

is by no means suitable to our plan to give a detailed account of this

new Platonic school; but we may notice a few of the writers who belong

to it, so far at least as to indicate its influence upon the Methods of

pursuing science.

In the fourteenth century[87], the frequent intercourse of the most

cultivated persons of the Eastern and Western Empire, the increased

study of the Greek language in Italy, the intellectual activity of the

Italian States, the discovery of manuscripts of the classical authors,

were circumstances which excited or nourished a new and zealous study

of the works of Greek and Roman genius. The genuine writings of the

ancients, when presented in their native life and beauty, instead of

being seen only in those lifeless fragments and dull transformations

which the scholastic system had exhibited, excited an intense

enthusiasm. Europe, at that period, might be represented by Plato's

beautiful allegory, of a man who, after being long kept in a dark

cavern, in which his knowledge of the external world is gathered from

the images which stream through the chinks of his prison, is at last

led forth into the full blaze of day. It was inevitable that such a

change should animate men's efforts and enlarge their faculties. Greek

literature became more and more known, especially by the influence of

learned men who came from Constantinople into Italy: these teachers,

though they honoured Aristotle, reverenced Plato no less, and had never

been accustomed to follow with servile submission of thought either

these or any other leaders. The effect of such influences soon reveals

itself in the works of that period. Dante has woven into his _Divina

Commedia_ some of the ideas of Platonism. Petrarch, who had formed his

mind by the study of Cicero, and had thus been inspired with a profound

admiration for the literature of Greece, learnt Greek from Barlaam, a

monk who came as ambassador from the Emperor of the East to the Pope,

in 1339. With this instructor, the poet read the works of Plato; struck

by their beauty, he contributed, by his writings and his conversation,

to awake in others an admiration and love for that philosopher, which

soon became strongly and extensively prevalent among the learned in

Italy.

3. _Hermolaus Barbarus, &c._--Along with the feeling there prevailed

also, among those who had learnt to relish the genuine beauties of

the Greek and Latin writers, a strong disgust for the barbarisms in

which the scholastic philosophy was clothed. Hermolaus Barbarus[88],

who was born in 1454, at Venice, and had formed his taste by the

study of classical literature, translated, among other learned works,

Themistius's paraphrastic expositions of the Physics of Aristotle;

with the view of trying whether the Aristotelian Natural Philosophy

could not be presented in good Latin, which the scholastic teachers

denied. In his Preface he expresses great indignation against those

philosophers who have written and disputed on philosophical subjects

in barbarous Latin, and in an uncultured style, so that all refined

minds are repelled from these studies by weariness and disgust. They

have, he says, by this barbarism, endeavoured to secure to themselves,

in their own province, a supremacy without rivals or opponents. Hence

they maintain that mathematics, philosophy, jurisprudence, cannot

be expounded in correct Latin;--that between these sciences and the

genuine Latin language there is a great gulf, as between things that

cannot be brought together: and on this ground they blame those who

combine the study of philology and eloquence with that of science.

This opinion, adds Hermolaus, perverts and ruins our studies; and is

highly prejudicial and unworthy in respect to the state. Hermolaus

awoke in others, as for instance, in John Picus of Mirandula, the same

dislike to the reigning school philosophy. As an opponent of the same

kind, we may add Marius Nizolius of Bersallo, a scholar who carried

his admiration of Cicero to an exaggerated extent, and who was led,

by a controversy with the defenders of the scholastic philosophy,

to publish (1553) a work _On the True Principles and True Method of

Philosophizing_. In the title of this work, he professes to give "the

true principles of almost all arts and sciences, refuting and rejecting

almost all the false principles of the Logicians and Metaphysicians."

But although, in the work, he attacks the scholastic philosophy, he

does little or nothing to justify the large pretensions of his title;

and he excited, it is said, little notice. It is therefore curious that

Leibnitz should have thought it worth his while to re-edit this work,

which he did in 1670, adding remarks of his own.

4. _Nicolaus Cusanus._--Without dwelling upon this opposition to the

scholastic system on the ground of taste, I shall notice somewhat

further those writers who put forwards Platonic views, as fitted to

complete or to replace the doctrines of Aristotle. Among these, I may

place Nicolaus Cusanus, (so called from Cus, a village on the Moselle,

where he was born in 1401;) who was afterwards raised to the dignity

of cardinal. We might, indeed, at first be tempted to include Cusanus

among those persons who were led to reject the old philosophy by being

themselves agents in the progressive movement of physical science.

For he published, before Copernicus, and independently of him, the

doctrine that the earth is in motion[89]. But it should be recollected

that in order to see the possibility of this doctrine, and its claims

to acceptance, no new reference to observation was requisite. The

Heliocentric System was merely a new mode of representing to the mind

facts, with which all astronomers had long been familiar. The system

might very easily have been embraced and inculcated by Plato himself;

as indeed it is said to have been actually taught by Pythagoras. The

mere adoption of the Heliocentric view, therefore, without attempting

to realize the system in detail, as Copernicus did, cannot entitle a

writer of the fifteenth century to be looked upon as one of the authors

of the discoveries of that period; and we must consider Cusanus as a

speculative anti-Aristotelian, rather than as a practical reformer.

The title of Cusanus's book, _De Doctâ Ignorantiâ_, shows how far

he was from agreeing with those who conceived that, in the works

of Aristotle, they had a full and complete system of all human

knowledge. At the outset of this book[90], he says, after pointing

out some difficulties in the received philosophy, "If, therefore,

the case be so, (as even the very profound Aristotle, in his _First

Philosophy_, affirms,) that in things most manifest by nature, there

is a difficulty, no less than for an owl to look at the sun; since

the appetite of knowledge is not implanted in us in vain, we ought

to desire to know that we are ignorant. If we can fully attain to

this, we shall arrive at _Instructed Ignorance_." How far he was from

placing the source of knowledge in experience, as opposed to ideas,

we may see in the following passage[91] from another work of his,

_On Conjectures_. "Conjectures must proceed from our mind, as the

real world proceeds from the infinite Divine Reason. For since the

human mind, the lofty likeness of God, participates, as it may, in

the fruitfulness of the creative nature, it doth from itself, as the

image of the Omnipotent Form, bring forth reasonable thoughts which

have a similitude to real existences. Thus the Human Mind exists as a

conjectural form of the world, as the Divine Mind is its real form." We

have here the Platonic or ideal side of knowledge put prominently and

exclusively forwards.

5. _Marsilius Ficinus, &c._--A person who had much more influence

on the diffusion of Platonism was Marsilius Ficinus, a physician

of Florence. In that city there prevailed, at the time of which we

speak, the greatest enthusiasm for Plato. George Gemistius Pletho,

when in attendance upon the Council of Florence, had imparted to

many persons the doctrines of the Greek philosopher; and, among

others, had infused a lively interest on this subject into the elder

Cosmo, the head of the family of the Medici. Cosmo formed the plan

of founding a Platonic academy. Ficinus[92], well instructed in the

works of Plato, Plotinus, Proclus, and other Platonists, was selected

to further this object, and was employed in translating the works of

these authors into Latin. It is not to our present purpose to consider

the doctrines of this school, except so far as they bear upon the

nature and methods of knowledge; and therefore I must pass by, as I

have in other instances done, the greater part of their speculations,

which related to the nature of God, the immortality of the soul, the

principles of Goodness and Beauty, and other points of the same order.

The object of these and other Platonists of this school, however, was

not to expel the authority of Aristotle by that of Plato. Many of

them had come to the conviction that the highest ends of philosophy

were to be reached only by bringing into accordance the doctrines

of Plato and of Aristotle. Of this opinion was John Picus, Count of

Mirandula and Concordia; and under this persuasion he employed the

whole of his life in labouring upon a work, _De Concordiâ Platonis et

Aristotelis_, which was not completed at the time of his death, in

1494; and has never been published. But about a century later, another

writer of the same school, Francis Patricius[93], pointing out the

discrepancies between the two Greek teachers, urged the propriety of

deposing Aristotle from the supremacy he had so long enjoyed. "Now all

these doctrines, and others not a few," he says[94], "since they are

Platonic doctrines, philosophically most true, and consonant with the

Catholic faith, whilst the Aristotelian tenets are contrary to the

faith, and philosophically false, who will not, both as a Christian and

a Philosopher, prefer Plato to Aristotle? And why should not hereafter,

in all the colleges and monasteries of Europe, the reading and study

of Plato be introduced? Why should not the philosophy of Aristotle be

forthwith exiled from such places? Why must men continue to drink the

mortal poison of impiety from that source?" with much more in the same

strain.

The Platonic school, of which we have spoken, had, however, reached

its highest point of prosperity before this time, and was already

declining. About 1500, the Platonists appeared to triumph over the

Peripatetics[95]; but the death of their great patron, Cardinal

Bessarion, about this time, and we may add, the hollowness of their

system in many points, and its want of fitness for the wants and

expectations of the age, turned men's thoughts partly back to the

established Aristotelian doctrines, and partly forwards to schemes of

bolder and fresher promise.

6. _Francis Patricius._--Patricius, of whom we have just spoken, was

one of those who had arrived at the conviction that the formation of

a new philosophy, and not merely the restoration of an old one, was

needed. In 1593, appeared his _Nova de Universis Philosophia_; and

the mode in which it begins[96] can hardly fail to remind us of the

expressions which Francis Bacon soon afterwards used in the opening of

a work of the same nature. "Francis Patricius, being about to found

anew the true philosophy of the universe, dared to begin by announcing

the following indisputable principles." Here, however, the resemblance

between Patricius and true inductive philosophers ends. His principles

are barren _à priori_ axioms; and his system has one main element,

_Light_, (_Lux_, or _Lumen_,) to which all operations of nature are

referred. In general cultivation, and practical knowledge of nature,

he was distinguished among his contemporaries. In various passages of

his works he relates[97] observations which he had made in the course

of his travels, in Cyprus, Corfu, Spain, the mountains of the Modenese,

and Dalmatia, which was his own country; his observations relate to

light, the saltness of the sea, its flux and reflux, and other points

of astronomy, meteorology, and natural history. He speaks of the sex of

plants[98]; rejects judicial astrology; and notices the astronomical

systems of Copernicus, Tycho, Fracastoro, and Torre. But the mode in

which he speaks of experiments proves, what indeed is evident from the

general scheme of his system, that he had no due appreciation of the

place which observation must hold in real and natural philosophy.

7. _Picus, Agrippa, &c._--It had been seen in the later philosophical

history of Greece, how readily the ideas of the Platonic school lead

on to a system of unfathomable and unbounded mysticism. John Picus,

of Mirandula[99], added to the study of Plato and the Neoplatonists,

a mass of allegorical interpretations of the Scriptures, and the

dreams of the Cabbala, a Jewish system[100], which pretends to explain

how all things are an emanation of the Deity. To this his nephew,

Francis Picus, added a reference to inward illumination[101], by which

knowledge is obtained, independently of the progress of reasoning.

John Reuchlin, or Capnio, born 1455; John Baptist Helmont, born 1577;

Francis Mercurius Helmont, born 1618, and others, succeeded John Picus

in his admiration of the Cabbala: while others, as Jacob Bœhmen,

rested upon internal revelations like Francis Picus. And thus we have

a series of mystical writers, continued into modern times, who may

be considered as the successors of the Platonic school; and who all

exhibit views altogether erroneous with regard to the nature and origin

of knowledge. Among the various dreams of this school are certain wide

and loose analogies of terrestrial and spiritual things. Thus in the

writings of Cornelius Agrippa (who was born 1487, at Cologne) we have

such systems as the following[102]:--"Since there is a threefold world,

elemental, celestial, and intellectual, and each lower one is governed

by that above it, and receives the influence of its powers: so that

the very Archetype and Supreme Author transfuses the virtues of his

omnipotence into us through angels, heavens, stars, elements, animals,

plants, stones,--into us, I say, for whose service he has framed and

created all these things;--the Magi do not think it irrational that

we should be able to ascend by the same degrees, the same worlds, to

this Archetype of the world, the Author and First Cause of all, of whom

all things are, and from whom they proceed; and should not only avail

ourselves of those powers which exist in the nobler works of creation,

but also should be able to attract other powers, and add them to these."

Agrippa's work, _De Vanitate Scientiarum_, may be said rather to

have a skeptical and cynical, than a Platonic, character. It is a

declamation[103], in a melancholy mood, against the condition of the

sciences in his time. His indignation at the worldly success of men

whom he considered inferior to himself, had, he says, metamorphosed him

into a dog, as the poets relate of Hecuba of Troy, so that his impulse

was to snarl and bark. His professed purpose, however, was to expose

the dogmatism, the servility, the self-conceit, and the neglect of

religious truth which prevailed in the reigning Schools of philosophy.

His views of the nature of science, and the modes of improving its

cultivation, are too imperfect and vague to allow us to rank him among

the reformers of science.

8. _Paracelsus, Fludd, &c._--The celebrated Paracelsus[104] put himself

forwards as a reformer in philosophy, and obtained no small number of

adherents. He was, in most respects, a shallow and impudent pretender;

and had small knowledge of the literature or science of his time:

but by the tone of his speaking and writing he manifestly belongs

to the mystical school of which we are now speaking. Perhaps by the

boldness with which he proposed new systems, and by connecting these

with the practical doctrines of medicine, he contributed something to

the introduction of a new philosophy. We have seen in the History of

Chemistry that he was the author of the system of Three Principles,

(salt, sulphur, and mercury,) which replaced the ancient doctrine of

Four Elements, and prepared the way for a true science of chemistry.

But the salt, sulphur, and mercury of Paracelsus were not, he tells his

disciples, the visible bodies which we call by those names, but certain

invisible, astral, or sidereal elements. The astral salt is the basis

of the solidity and incombustible parts in bodies; the astral sulphur

is the source of combustion and vegetation; the astral mercury is the

origin of fluidity and volatility. And again, these three elements are

analogous to the three elements of man,--Body, Spirit, and Soul.

A writer of our own country, belonging to this mystical school, is

Robert Fludd, or De Fluctibus, who was born in 1571, in Kent, and

after pursuing his studies at Oxford, travelled for several years.

Of all the Theosophists and Mystics, he is by much the most learned;

and was engaged in various controversies with Mersenne, Gassendi,

Kepler, and others. He thus brings us in contact with the next class

of philosophers whom we have to consider, the practical reformers

of philosophy;--those who furthered the cause of science by making,

promulgating, or defending the great discoveries which now began

to occupy men. He adopted the principle, which we have noticed

elsewhere[105], of the analogy of the Macrocosm and Microcosm, the

world of nature and the world of man. His system contains such a

mixture and confusion of physical and metaphysical doctrines as might

be expected from his ground-plan, and from his school. Indeed his

object, the general object of mystical speculators, is to identify

physical with spiritual truths. Yet the influence of the practical

experimental philosophy which was now gaining ground in the world may

be traced in him. Thus he refers to experiments on distillation to

prove the existence and relation of the regions of water, air, and

fire, and of the spirits which correspond to them; and is conceived, by

some persons[106], to have anticipated Torricelli in the invention of

the Barometer.

We need no further follow the speculations of this school. We see

already abundant reason why the reform of the methods of pursuing

science could not proceed from the Platonists. Instead of seeking

knowledge by experiment, they immersed themselves deeper than even the

Aristotelians had done in traditionary lore, or turned their eyes

inwards in search of an internal illumination. Some attempts were made

to remedy the defects of philosophy by a recourse to the doctrines

of other sects of antiquity, when men began to feel more distinctly

the need of a more connected and solid knowledge of nature than the

established system gave them. Among these attempts were those of

Berigard[107], Magernus, and especially Gassendi, to bring into repute

the philosophy of the Ionian school, of Democritus and of Epicurus. But

these endeavours were posterior in time to the new impulse given to

knowledge by Copernicus, Kepler, and Galileo, and were influenced by

views arising out of the success of these discoveries, and they must,

therefore, be considered hereafter. In the mean time, some independent

efforts (arising from speculative rather than practical reformers)

were made to cast off the yoke of the Aristotelian dogmatism, and to

apprehend the true form of that new philosophy which the most active

and hopeful minds saw to be needed; and we must give some account of

these attempts, before we can commit ourselves to the full stream of

progressive philosophy.

FOOTNOTES:

[Footnote 86: Gratian published the _Decretals_ in the twelfth century;

and the Canon and Civil Law became a regular study in the universities

soon afterwards.]

[Footnote 87: Tenneman, ix. 4.]

[Footnote 88: Tenneman, ix. 25.]

[Footnote 89: "Jam nobis manifestum est terram istam in veritate

moveri," &c.--_De Doctâ Ignorantiâ_, lib. ii. c. xii.]

[Footnote 90: _De Doct. Ignor._ lib. i. c. i.]

[Footnote 91: _De Conjecturis_, lib. i. c. iii. iv.]

[Footnote 92: Born in 1433.]

[Footnote 93: Born 1529, died 1597.]

[Footnote 94: _Aristoteles Exotericus_, p. 50.]

[Footnote 95: Tiraboschi, t. vii. pt. ii. p. 411.]

[Footnote 96: "Franciscus Patricius, novam veram integram de universis

conditurus philosophiam, sequentia uti verissima prænuntiare est

ausus. Prænunciata ordine persecutus, divinis oraculis, geometricis

rationibus, clarissimisque experimentis comprobavit.

Ante primum nihil,

Post primum omnia,

A principio omnia," &c.

His other works are _Panaugia_, _Pancosmia_, _Dissertations

Peripateticæ_.]

[Footnote 97: Tiraboschi, t. vii. pt. ii. p. 411.]

[Footnote 98: _Dissert. Perip._ t. ii. lib. v. sub fin.]

[Footnote 99: Tenneman, ix. 148.]

[Footnote 100: Tenneman, ix. 167.]

[Footnote 101: _Ibid._ 158.]

[Footnote 102: Agrippa, _De Occult. Phil._ lib. i. c. l.]

[Footnote 103: Written in 1526.]

[Footnote 104: Philip Aurelius Theophrastus Bombastus von Hohenheim,

also called Paracelsus Eremita, born at Einsiedlen in Switzerland, in

1493.]

[Footnote 105: _Hist. Sc. Id._ b. ix. c. 2. sect. 1. The Mystical

School of Biology.]

[Footnote 106: Tenneman, ix. 221.]

[Footnote 107: Tenneman, ix. 265.]

CHAPTER XIII.

THE THEORETICAL REFORMERS OF SCIENCE.

We have already seen that Patricius, about the middle of the sixteenth

century, announced his purpose of founding anew the whole fabric

of philosophy; but that, in executing this plan, he ran into wide

and baseless hypotheses, suggested by _à priori_ conceptions rather

than by external observation; and that he was further misled by

fanciful analogies resembling those which the Platonic mystics loved

to contemplate. The same time, and the period which followed it,

produced several other essays which were of the same nature, with the

exception of their being free from the peculiar tendencies of the

Platonic school: and these insurrections against the authority of

the established dogmas, although they did not directly substitute a

better positive system in the place of that which they assailed, shook

the authority of the Aristotelian system, and led to its overthrow;

which took place as soon as these theoretical reformers were aided by

practical reformers.

1. _Bernardinus Telesius._--Italy, always, in modern times, fertile in

the beginnings of new systems, was the soil on which these innovators

arose. The earliest and most conspicuous of them is Bernardinus

Telesius, who was born in 1508, at Cosenza, in the kingdom of Naples.

His studies, carried on with great zeal and ability, first at Milan

and then at Rome, made him well acquainted with the knowledge of

his times; but his own reflections convinced him that the basis of

science, as then received, was altogether erroneous; and led him to

attempt a reform, with which view, in 1565, he published, at Rome,

his work[108], "_Bernardinus Telesius, of Cosenza, on the Nature of

Things, according to principles of his own_." In the preface of this

work he gives a short account[109] of the train of reflection by which

he was led to put himself in opposition to the Aristotelian philosophy.

This kind of autobiography occurs not unfrequently in the writings of

theoretical reformers; and shows how livelily they felt the novelty of

their undertaking. After the storm and sack of Rome in 1527, Telesius

retired to Padua, as a peaceful seat of the muses; and there studied

philosophy and mathematics, with great zeal, under the direction of

Jerome Amalthæus and Frederic Delphinus. In these studies he made great

progress; and the knowledge which he thus acquired threw a new light

upon his view of the Aristotelian philosophy. He undertook a closer

examination of the Physical Doctrines of Aristotle; and as the result

of this, he was astonished how it could have been possible that so

many excellent men, so many nations, and even almost the whole human

race, should, for so long a time, have allowed themselves to be carried

away by a blind reverence for a teacher, who had committed errors so

numerous and grave as he perceived to exist in "the philosopher." Along

with this view of the insufficiency of the Aristotelian philosophy,

arose, at an early period, the thought of erecting a better system in

its place. With this purpose he left Padua, when he had received the

degree of Doctor, and went to Rome, where he was encouraged in his

design by the approval and friendly exhortations of distinguished men

of letters, amongst whom were Ubaldino Bandinelli and Giovanni della

Casa. From Rome he went to his native place, when the incidents and

occupations of a married life for a while interrupted his philosophical

project. But after his wife was dead, and his eldest son grown to

manhood, he resumed with ardour the scheme of his youth; again studied

the works of Aristotle and other philosophers, and composed and

published the first two books of his treatise. The opening to this

work sufficiently exhibits the spirit in which it was conceived. Its

object is stated in the title to be to show, that "the construction

of the world, the magnitude and nature of the bodies contained in

it, are not to be investigated by reasoning, which was done by the

ancients, but are to be apprehended by the senses, and collected from

the things themselves." And the Proem is in the same strain. "They who

before us have inquired concerning the construction of this world and

of the things which it contains, seem indeed to have prosecuted their

examination with protracted vigils and great labour, but _never to have

looked at it_." And thus, he observes, they found nothing but error.

This he ascribes to their presumption. "For, as it were, attempting

to rival God in wisdom, and venturing to seek for the principles and

causes of the world by the light of their own reason, and thinking they

had found what they had only invented, they made an arbitrary world of

their own." "_We_ then," he adds, "not relying on ourselves, and of a

duller intellect than they, propose to ourselves to turn our regards to

the world itself and its parts."

The execution of the work, however, by no means corresponds to the

announcement. The doctrines of Aristotle are indeed attacked; and the

objections to these, and to other received opinions, form a large

part of the work. But these objections are supported by _à priori_

reasoning, and not by experiments. And thus, rejecting the Aristotelian

physics, he proposes a system at least equally baseless; although, no

doubt, grateful to the author from its sweeping and apparently simple

character. He assumes three principles, Heat, Cold, and Matter: Heat

is the principle of motion, Cold of immobility, and Matter is the

corporeal substratum, in which these incorporeal and active principles

produce their effects. It is easy to imagine that, by combining and

separating these abstractions in various ways, a sort of account of

many natural phenomena may be given; but it is impossible to ascribe

any real value to such a system. The merit of Telesius must be

considered to consist in his rejection of the Aristotelian errors,

in his perception of the necessity of a reform in the method of

philosophizing, and in his persuasion that this reform must be founded

on experiments rather than on reasoning. When he said[110], "We propose

to ourselves to turn our eyes to the world itself, and its parts, their

passions, actions, operations, and species," his view of the course to

be followed was right; but his purpose remained but ill fulfilled, by

the arbitrary edifice of abstract conceptions which his system exhibits.

Francis Bacon, who, about half a century later, treated the subject

of a reform of philosophy in a far more penetrating and masterly

manner, has given us his judgment of Telesius. In his view, he takes

Telesius as the restorer of the Atomic philosophy, which Democritus

and Parmenides taught among the ancients; and according to his

custom, he presents an image of this philosophy in an adaptation of

a portion of ancient mythology[111]. The Celestial Cupid, who with

Cœlus, was the parent of the Gods and of the Universe, is exhibited

as a representation of matter and its properties, according to the

Democritean philosophy. "Concerning Telesius," says Bacon, "we think

well, and acknowledge him as a lover of truth, a useful contributor to

science, an amender of some tenets, the first of recent men. But we

have to do with him as the restorer of the philosophy of Parmenides,

to whom much reverence is due." With regard to this philosophy,

he pronounces a judgment which very truly expresses the cause of

its rashness and emptiness. "It is," he says, "such a system[112]

as naturally proceeds from the intellect, abandoned to its own

impulse, and not rising from experience to theory continuously and

successively." Accordingly, he says that, "Telesius, although learned

in the Peripatetic philosophy (if that were anything), which indeed, he

has turned against the teachers of it, is hindered by his affirmations,

and is more successful in destroying than in building."

The work of Telesius excited no small notice, and was placed in the

_Index Expurgatorius_. It made many disciples, a consequence probably

due to its spirit of system-making, no less than to its promise of

reform, or its acuteness of argument; for till trial and reflection

have taught man modesty and moderation, he can never be content to

receive knowledge in the small successive instalments in which nature

gives it forth to him. It is the makers of large systems, arranged with

an _appearance_ of completeness and symmetry, who, principally, give

rise to Schools of philosophy.

2. (_Thomas Campanella_).--Accordingly, Telesius may be looked upon as

the founder of a School. His most distinguished successor was Thomas

Campanella, who was born in 1568, at Stilo, in Calabria. He showed

great talents at an early age, prosecuting his studies at Cosenza,

the birth-place of the great opponent of Aristotle and reformer of

philosophy. He, too, has given us an account[113] of the course of

thought by which he was led to become an innovator. "Being afraid

that not genuine truth, but falsehood in the place of truth, was the

tenant of the Peripatetic School, I examined all the Greek, Latin,

and Arabic commentators of Aristotle, and hesitated more and more, as

I sought to learn whether what they have said were also to be read

in the world itself, which I had been taught by learned men was the

living book of God. And as my doctors could not satisfy my scruples,

I resolved to read all the books of Plato, Pliny, Galen, the Stoics,

and the Democriteans, and especially those of Telesius; and to compare

them with that _first and original writing, the world_; that thus from

the primary autograph, I might learn if the copies contained anything

false." Campanella probably refers here to an expression of Plato,

who says, "the world is God's epistle to mankind." And this image, of

the natural world as an original manuscript, while human systems of

philosophy are but copies, and may be false ones, became a favourite

thought of the reformers, and appears repeatedly in their writings from

this time. "When I held my public disputation at Cosenza," Campanella

proceeds, "and still more, when I conversed privately with the brethren

of the monastery, I found little satisfaction in their answers; but

Telesius delighted me, on account of his freedom in philosophizing,

and because he rested upon the nature of things, and not upon the

assertions of men."

With these views and feelings, it is not wonderful that Campanella,

at the early age of twenty-two (1590,) published a work remarkable

for the bold promise of its title: "_Thomas Campanella's Philosophy

demonstrated to the senses, against those who have philosophized in an

arbitrary and dogmatical manner, not taking nature for their guide; in

which the errors of Aristotle and his followers are refuted from their

own assertions and the laws of nature: and all the imaginations feigned

in the place of nature by the Peripatetics are altogether rejected;

with a true defence of Bernardin Telesius of Cosenza, the greatest

of philosophers; confirmed by the opinions of the ancients, here

elucidated and defended, especially those of the Platonists_."

This work was written in answer to a book published against Telesius

by a Neapolitan professor named Marta; and it was the boast of the

young author that he had only employed eleven months in the composition

of his defence, while his adversary had been engaged eleven years

in preparing his attack. Campanella found a favourable reception in

the house of the Marchese Lavelli, and there employed himself in the

composition of an additional work, entitled _On the Sense of Things

and Magic_, and in other literary labours. These, however, are full

of the indications of an enthusiastic temper, inclined to mystical

devotion, and of opinions bearing the cast of pantheism. For instance,

the title of the book last quoted sets forth as demonstrated in the

course of the work, that "the world is the living and intelligent

statue of God; and that all its parts, and particles of parts, are

endowed some with a clearer, some with a more obscure sense, such

as suffices for the preservation of each and of the whole." Besides

these opinions, which could not fail to make him obnoxious to the

religious authorities, Campanella[114] engaged in schemes of political

revolution, which involved him in danger and calamity. He took part

in a conspiracy, of which the object was to cast off the tyranny of

Spain, and to make Calabria a republic. This design was discovered; and

Campanella, along with others, was thrown into prison and subjected to

torture. He was kept in confinement twenty-seven years; and at last

obtained his liberation by the interposition of Pope Urban VIII. He

was, however, still in danger from the Neapolitan Inquisition; and

escaped in disguise to Paris, where he received a pension from the

king, and lived in intercourse with the most eminent men of letters. He

died there in 1639.

Campanella was a contemporary of Francis Bacon, whom we must consider

as belonging to an epoch to which the Calabrian school of innovators

was only a prelude. I shall not therefore further follow the connexion

of writers of this order. Tobias Adami, a Saxon writer, an admirer

of Campanella's works, employed himself, about 1620, in adapting

them to the German public, and in recommending them strongly to

German philosophers. Descartes, and even Bacon, may be considered as

successors of Campanella; for they too were theoretical reformers; but

they enjoyed the advantage of the light which had, in the mean time,

been thrown upon the philosophy of science, by the great practical

advances of Kepler, Galileo, and others. To these practical reformers

we must soon turn our attention: but we may first notice one or two

additional circumstances belonging to our present subject.

Campanella remarks that both the Peripatetics and the Platonists

conducted the learner to knowledge by a long and circuitous path, which

he wished to shorten by setting out from the sense. Without speaking

of the methods which he proposed, we may notice one maxim[115] of

considerable value which he propounds, and to which we have already

been led. "We begin to reason from sensible objects, and definition

is the end and epilogue of science. It is not the beginning of our

knowing, but only of our teaching."

3. (_Andrew Cæsalpinus._)--The same maxim had already been announced

by Cæsalpinus, a contemporary of Telesius; (he was born at Arezzo in

1520, and died at Rome in 1603). Cæsalpinus is a great name in science,

though professedly an Aristotelian. It has been seen in the _History

of Science_[116], that he formed the first great epoch of the science

of botany by his systematic arrangement of plants, and that in this

task he had no successor for nearly a century. He also approached near

to the great discovery of the circulation of the blood[117]. He takes

a view of science which includes the remark that we have just quoted

from Campanella: "We reach perfect knowledge by three steps: Induction,

Division, Definition. By Induction, we collect likeness and agreement

from observation; by Division, we collect unlikeness and disagreement;

by Definition, we learn the proper substance of each object. Induction

makes universals from particulars, and offers to the mind all

intelligible matter; Division discovers the difference of universals,

and leads to species; Definition resolves species into their principles

and elements[118]." Without asserting this to be rigorously correct, it

is incomparably more true and philosophical than the opposite view,

which represents definition as the beginning of our knowledge; and

the establishment of such a doctrine is a material step in inductive

philosophy[119].

4. (_Giordano Bruno._)--Among the Italian innovators of this time

we must notice the unfortunate Giordano Bruno, who was born at Nola

about 1550 and burnt at Rome in 1600. He is, however, a reformer of a

different school from Campanella; for he derives his philosophy from

Ideas and not from Observation. He represents himself as the author of

a new doctrine, which he terms the _Nolan Philosophy_. He was a zealous

promulgator and defender of the Copernican system of the universe, as

we have noticed in the _History of Science_[120]. Campanella also wrote

in defence of that system.

It is worthy of remark that a thought which is often quoted from

Francis Bacon, occurs in Bruno's _Cena di Cenere_, published in

1584; I mean, the notion that the later times are more aged than

the earlier. In the course of the dialogue, the Pedant, who is one

of the interlocutors, says, "In antiquity is wisdom;" to which the

Philosophical Character replies, "If you knew what you were talking

about, you would see that your principle leads to the opposite result

of that which you wish to infer;--I mean, that _we_ are older, and have

lived longer, than our predecessors." He then proceeds to apply this,

by tracing the course of astronomy through the earlier astronomers up

to Copernicus.

5. (_Peter Ramus._)--I will notice one other reformer of this period,

who attacked the Aristotelian system on another side, on which it

was considered to be most impregnable. This was Peter Ramus,(born in

Picardy in 1515,) who ventured to denounce the _Logic_ of Aristotle as

unphilosophical and useless. After showing an extraordinary aptitude

for the acquirement of knowledge in his youth, when he proceeded to

the degree of Master of Arts, he astonished his examiners by choosing

for the subject of the requisite disputation the thesis[121], "that

what Aristotle has said is all wrong." This position, so startling in

1535, he defended for the whole day, without being defeated. This was,

however, only a formal academical exercise, which did not necessarily

imply any permanent conviction of the opinion thus expressed. But his

mind was really labouring to detect and remedy the errors which he

thus proclaimed. From him, as from the other reformers of this time,

we have an account of this mental struggle[122]. He says, in a work on

this subject, "I will candidly and simply explain how I was delivered

from the darkness of Aristotle. When, according to the laws of our

university, I had spent three years and a half in the Aristotelian

philosophy, and was now invested with the philosophical laurel as a

Master of Arts, I took an account of the time which I had consumed

in this study, and considered on what subjects I should employ this

logical art of Aristotle, which I had learnt with so much labour and

noise, I found it made me not more versed in history or antiquities,

more eloquent in discourse, more ready in verse, more wise in any

subject. Alas for me! how was I overpowered, how deeply did I groan,

how did I deplore my lot and my nature, how did I deem myself to be

by some unhappy and dismal fate and frame of mind abhorrent from the

Muses, when I found that I was one who, after all my pains, could

reap no benefit from that wisdom of which I heard so much, as being

contained in the Logic of Aristotle." He then relates that he was

led to the study of the Dialogues of Plato, and was delighted with

the kind of analysis of the subjects discussed which Socrates is

there represented as executing. "Well," he adds, "I began thus to

reflect within myself--(I should have thought it impious to say it to

another)--What, I pray you, prevents me from _socratizing_; and from

asking, without regard to Aristotle's authority, whether Aristotle's

Logic be true and correct? It may be that that philosopher leads

us wrong; and if so, no wonder that I cannot find in his books the

treasure which is not there. What if his dogmas be mere figments? Do

I not tease and torment myself in vain, trying to get a harvest from

a barren soil?" He convinced himself that the Aristotelian logic was

worthless: and constructed a new system of Logic, founded mainly on the

Platonic process of exhausting a subject by analytical classification

of its parts. Both works, his _Animadversions on Aristotle_, and his

_Logic_, appeared in 1543. The learned world was startled and shocked

to find a young man, on his first entrance into life, condemning

as faulty, fallacious, and useless, that part of Aristotle's works

which had always hitherto been held as a masterpiece of philosophical

acuteness, and as the Organon of scientific reasoning. And in truth, it

must be granted that Ramus does not appear to have understood the real

nature and object of Aristotle's Logic; while his own system could not

supply the place of the old one, and was not of much real value. This

dissent from the established doctrines was, however, not only condemned

but punished. The printing and selling of his books was forbidden

through France; and Ramus was stigmatized by a sentence[123] which

declared him rash, arrogant, impudent, and ignorant, and prohibited

from teaching logic and philosophy. He was, however, afterwards

restored to the office of professor: and though much attacked,

persisted in his plan of reforming, not only Logic but Physics and

Metaphysics. He made his position still more dangerous by adopting the

reformed religion; and during the unhappy civil wars of France, he was

deprived of his professorship, driven from Paris, and had his library

plundered. He endeavoured, but in vain, to engage a German professor,

Schegk, to undertake the reform of the Aristotelian Physics; a portion

of knowledge in which he felt himself not to be strong. Unhappily for

himself, he afterwards returned to Paris, where he perished in the

massacre of St. Bartholomew in 1572.

Ramus's main objection to the Aristotelian Logic is, that it is not

the image of the natural process of thought; an objection which shows

little philosophical insight; for the course by which we obtain

knowledge may well differ from the order in which our knowledge,

when obtained, is exhibited. We have already seen that Ramus's

contemporaries, Cæsalpinus and Campanella, had a wiser view; placing

definition as the last step in knowing, but the first in teaching.

But the effect which Ramus produced was by no means slight. He aided

powerfully in turning the minds of men to question the authority of

Aristotle on all points; and had many followers, especially among the

Protestants. Among the rest, Milton, our great poet, published "Artis

Logicæ plenior Institutio _ad Petri Rami methodum concinnata_;" but

this work, appearing in 1672, belongs to a succeeding period.

6. (_The Reformers in general_).--It is impossible not to be struck

with the series of misfortunes which assailed the reformers of

philosophy of the period we have had to review. Roger Bacon was

repeatedly condemned and imprisoned; and, not to speak of others who

suffered under the imputation of magical arts, Telesius is said[124] to

have been driven from Naples to his native city by calumny and envy;

Cæsalpinus was accused of atheism[125]; Campanella was imprisoned for

twenty-seven years and tortured; Giordano Bruno was burnt at Rome as

a heretic; Ramus was persecuted during his life, and finally murdered

by his personal enemy Jacques Charpentier, in a massacre of which the

plea was religion. It is true, that for the most part these misfortunes

were not principally due to the attempts at philosophical reform, but

were connected rather with politics or religion. But we cannot doubt

that the spirit which led men to assail the received philosophy, might

readily incline them to reject some tenets of the established religion;

since the boundary line of these subjects is difficult to draw. And as

we have seen, there was in most of the persons of whom we have spoken,

not only a well-founded persuasion of the defects of existing systems,

but an eager spirit of change, and a sanguine anticipation of some

wide and lofty philosophy, which was soon to elevate the minds and

conditions of men. The most unfortunate were, for the most part, the

least temperate and judicious reformers. Patricius, who, as we have

seen, declared himself against the Aristotelian philosophy, lived and

died at Rome in peace and honour[126].

7. (_Melancthon._)--It is not easy to point out with precision the

connexion between the efforts at a Reform in Philosophy, and the great

Reformation of Religion in the sixteenth century. The disposition to

assert (practically at least) a freedom of thinking, and to reject the

corruptions which tradition had introduced and authority maintained,

naturally extended its influence from one subject to another; and

especially in subjects so nearly connected as theology and philosophy.

The Protestants, however, did not reject the Aristotelian system;

they only reformed it, by going back to the original works of the

author, and by reducing it to a conformity with Scripture. In this

reform, Melancthon was the chief author, and wrote works on Logic,

Physics, Morals, and Metaphysics, which were used among Protestants.

On the subject of the origin of our knowledge, his views contained

a very philosophical improvement of the Aristotelian doctrines. He

recognized the importance of Ideas, as well as of Experience. "We could

not," he says[127], "proceed to reason at all, except there were by

nature innate in man certain fixed points, that is, principles of

science;--as Number, the recognition of Order and Proportion, logical,

geometrical, physical and moral Principles. Physical principles are

such as these,--everything which exists proceeds from a cause,--a body

cannot be in two places at once,--time is a continued series of things

or of motions,--and the like." It is not difficult to see that such

Principles partake of the nature of the Fundamental Ideas which we have

attempted to arrange and enumerate in a previous part of this work.

Before we proceed to the next chapter, which treats of the Practical

Reformers of Scientific Method, let us for an instant look at the

strong persuasion implied in the titles of the works of this period,

that the time of a philosophical revolution was at hand. Telesius

published _De Rerum Natura juxta propria principia_; Francis Helmont,

_Philosophia vulgaris refutata_; Patricius, _Nova de Universis

Philosophia_; Campanella, _Philosophia sensibus demonstrata, adversus

errores Aristotelis_; Bruno professed himself the author of a _Nolan

Philosophy_; and Ramus of a _New Logic_. The age announced itself

pregnant; and the eyes of all who took an interest in the intellectual

fortunes of the race, were looking eagerly for the expected offspring.

FOOTNOTES:

[Footnote 108: Bernardini Telesii Consentini _De Rerum Natura juxta

propria Principia_.]

[Footnote 109: I take this account from Tenneman: this Proem was

omitted in subsequent editions of Telesius, and is not in the one which

I have consulted. Tenneman, _Gesch. d. Phil._ ix. 280.]

[Footnote 110: Proem.]

[Footnote 111: "De Principiis atque Originibus secundum fabulas

Cupidinis et Cœli: sive Parmenidis et Telesii et præcipuè Democriti

Philosophia tractata in Fabula de Cupidine."]

[Footnote 112: "Talia sunt qualia possunt esse ea quæ ab intellectu

sibi permisso, nec ab experimentis continenter et gradatim sublevato,

profecta videntur."]

[Footnote 113: Thom. Campanella _de Libris propriis_, as quoted in

Tenneman, ix. 291.]

[Footnote 114: _Economisti Italiani_, t. i. p. xxxiii.]

[Footnote 115: Tenneman, ix. 305.]

[Footnote 116: _Hist. Ind. Sc._ b. xvi. c. iii. sect. 2.]

[Footnote 117: _Ibid._ b. xvii. c. ii. sect. 1.]

[Footnote 118: _Quæst. Peripat._ i. 1.]

[Footnote 119: Tenneman, ix. 108.]

[Footnote 120: _Hist. Ind. Sc._ b. v. c. iii. sect. 2.]

[Footnote 121: Tenneman, ix. 420. "Quæcunque ab Aristotele dicta essent

commenticia esse." Freigius, _Vita Petri Rami_, p. 10.]

[Footnote 122: Rami, _Animadv. Aristot._ i. iv.]

[Footnote 123: See _Hist. Ind. Sc._ b. iv. c. iv. sect. 4.]

[Footnote 124: Tenneman, ix. 230.]

[Footnote 125: _Ibid._ 108.]

[Footnote 126: Tenneman, ix. 246.]

[Footnote 127: Melancthon, _De Anima_, p. 207, quoted in Tenneman, ix.

121.]

CHAPTER XIV.

THE PRACTICAL REFORMERS OF SCIENCE.

1. _Character of the Practical Reformers._--We now come to a class

of speculators who had perhaps a greater share in bringing about the

change from stationary to progressive knowledge, than those writers who

so loudly announced the revolution. The mode in which the philosophers

of whom we now speak produced their impressions on men's minds, was

very different from the procedure of the theoretical reformers. What

these talked of, they did; what these promised, they performed. While

the theorists concerning knowledge proclaimed that great advances

were to be made, the practical discoverers went steadily forwards.

While one class spoke of a complete Reform of scientific Methods, the

other, boasting little, and often thinking little of Method, proved

the novelty of their instrument by obtaining new results. While the

metaphysicians were exhorting men to consult experience and the senses,

the physicists were examining nature by such means with unparalleled

success. And while the former, even when they did for a moment refer

to facts, soon rushed back into their own region of ideas, and tried

at once to seize the widest generalizations, the latter, fastening

their attention upon the phenomena, and trying to reduce them to

laws, were carried forwards by steps measured and gradual, such as no

conjectural view of scientific method had suggested; but leading to

truths as profound and comprehensive as any which conjecture had dared

to anticipate. The theoretical reformers were bold, self-confident,

hasty, contemptuous of antiquity, ambitious of ruling all future

speculations, as they whom they sought to depose had ruled the past.

The practical reformers were cautious, modest, slow, despising no

knowledge, whether borrowed from tradition or observation, confident in

the ultimate triumph of science, but impressed with the conviction that

each single person could contribute a little only to its progress. Yet

though thus working rather than speculating,--dealing with particulars

more than with generals,--employed mainly in adding to knowledge, and

not in defining what knowledge is, or how additions are to be made

to it,--these men, thoughtful, curious, and of comprehensive minds,

were constantly led to important views on the nature and methods of

science. And these views, thus suggested by reflections on their own

mental activity, were gradually incorporated with the more abstract

doctrines of the metaphysicians, and had a most important influence

in establishing an improved philosophy of science. The indications of

such views we must now endeavour to collect from the writings of the

discoverers of the times preceding the seventeenth century.

Some of the earliest of these indications are to be found in those who

dealt with Art rather than with Science. I have already endeavoured

to show that the advance of the arts which give us a command over the

powers of nature, is generally prior to the formation of exact and

speculative knowledge concerning those powers. But Art, which is thus

the predecessor of Science, is, among nations of acute and active

intellects, usually its parent. There operates, in such a case, a

speculative spirit, leading men to seek for the reasons of that which

they find themselves able to do. How slowly, and with what repeated

deviations men follow this leading, when under the influence of a

partial and dogmatical philosophy, the late birth and slow growth of

sound physical theory shows. But at the period of which we now speak,

we find men, at length, proceeding in obedience to the impulse which

thus drives them from practice to theory;--from an acquaintance with

phenomena to a free and intelligent inquiry concerning their causes.

2. _Leonardo da Vinci._--I have already noted, in the History of

Science, that the Indistinctness of Ideas, which was long one main

impediment to the progress of science in the middle ages, was first

remedied among architects and engineers. These men, so far at least as

mechanical ideas were concerned, were compelled by their employments

to judge rightly of the relations and properties of the materials with

which they had to deal; and would have been chastised by the failure

of their works, if they had violated the laws of mechanical truth. It

was not wonderful, therefore, that these laws became known to _them_

first. We have seen, in the _History_, that Leonardo da Vinci, the

celebrated painter, who was also an engineer, is the first writer in

whom we find the true view of the laws of equilibrium of the lever in

the most general case. This artist, a man of a lively and discursive

mind, is led to make some remarks[128] on the formation of our

knowledge, which may show the opinions on that subject that already

offered themselves at the beginning of the sixteenth century[129]. He

expresses himself as follows:--"Theory is the general, Experiments are

the soldiers. The interpreter of the artifices of nature is Experience:

she is never deceived. Our judgment sometimes is deceived, because it

expects effects which Experience refuses to allow." And again, "We

must consult Experience, and vary the circumstances till we have drawn

from them general rules; for it is she who furnishes true rules. But

of what use, you ask, are these rules; I reply, that they direct us in

the researches of nature and the operations of art. They prevent our

imposing upon ourselves and others by promising ourselves results which

we cannot obtain.

"In the study of the sciences which depend on mathematics, those who do

not consult nature but authors, are not the children of nature, they

are only her grandchildren. She is the true teacher of men of genius.

But see the absurdity of men! They turn up their noses at a man who

prefers to learn from nature herself rather than from authors who are

only her clerks."

In another place, in reference to a particular case, he says, "Nature

begins from the Reason and ends in Experience; but for all that, we

must take the opposite course; begin from the Experiment and try to

discover the Reason."

Leonardo was born forty-six years before Telesius; yet we have here

an estimate of the value of experience far more just and substantial

than the Calabrian school ever reached. The expressions contained in

the above extracts, are well worthy our notice;--that experience is

never deceived;--that we must vary our experiments, and draw from them

general rules;--that nature is the original source of knowledge, and

books only a derivative substitute;--with a lively image of the sons

and grandsons of nature. Some of these assertions have been deemed,

and not without reason, very similar to those made by Bacon a century

later. Yet it is probable that the import of such expressions, in

Leonardo's mind, was less clear and definite than that which they

acquired by the progress of sound philosophy. When he says that theory

is the general and experiments the soldiers, he probably meant that

theory directs men what experiments to make; and had not in his mind

the notion of a theoretical Idea ordering and brigading the Facts. When

he says that Experience is the interpreter of Nature, we may recollect,

that in a more correct use of this image, Experience and Nature are the

writing, and the Intellect of man the interpreter. We may add, that

the clear apprehension of the importance of Experience led, in this as

in other cases, to an unjust depreciation of the value of what science

owed to books. Leonardo would have made little progress, if he had

attempted to master a complex science, astronomy for instance, by means

of observation alone, without the aid of books.

But in spite of such criticism, Leonardo's maxims show extraordinary

sagacity and insight; and they appear to us the more remarkable, when

we see how rare such views are for a century after his time.

3. _Copernicus._--For we by no means find, even in those practical

discoverers to whom, in reality, the revolution in science, and

consequently in the philosophy of science, was due, this prompt and

vigorous recognition of the supreme authority of observation as a

ground of belief; this bold estimate of the probable worthlessness

of traditional knowledge; and this plain assertion of the reality of

theory founded upon experience. Among such discoverers, Copernicus must

ever hold a most distinguished place. The heliocentric theory of the

universe, established by him with vast labour and deep knowledge, was,

for the succeeding century, the field of discipline and exertion of all

the most active speculative minds. Men, during that time, proved their

freedom of thought, their hopeful spirit, and their comprehensive view,

by adopting, inculcating, and following out the philosophy which this

theory suggested. But in the first promulgation of the theory, in the

works of Copernicus himself, we find a far more cautious and reserved

temper. He does not, indeed, give up the reality of his theory, but

he expresses himself so as to avoid shocking those who might (as some

afterwards did) think it safe to speak of it as an _hypothesis_ rather

than a truth. In his preface addressed to the Pope[130], after speaking

of the difficulties in the old and received doctrines, by which he

was led to his own theory, he says, "Hence I began to think of the

mobility of the earth; and although the opinion seemed absurd, yet

because I knew that to others before me this liberty had been conceded,

of imagining any kinds of circles in order to explain the phenomena

of the stars, I thought it would also be readily granted me, that I

might try whether, by supposing the earth to be in motion, I might

not arrive at a better explanation than theirs, of the revolutions of

the celestial orbs." Nor does he anywhere assert that the seeming

absurdity had become a certain truth, or betray any feeling of triumph

over the mistaken belief of his predecessors. And, as I have elsewhere

shown, his disciples[131] indignantly and justly defended him from the

charge of disrespect towards Ptolemy and other ancient astronomers. Yet

Copernicus is far from compromising the value or evidence of the great

truths which he introduced to general acceptance; and from sinking in

his exposition of his discoveries below the temper which had led to

them. His quotation from Ptolemy, that "He who is to follow philosophy

must be a freeman in mind," is a grand and noble maxim, which it well

became him to utter.

4. _Fabricius._--In another of the great discoverers of this period,

though employed on a very different subject, we discern much of the

same temper. Fabricius of Acquapendente[132], the tutor and forerunner

of our Harvey, and one of that illustrious series of Paduan professors

who were the fathers of anatomy[133], exhibits something of the same

respect for antiquity, in the midst of his original speculations.

Thus in a dissertation[134] _On the Action of the Joints_, he quotes

Aristotle's Mechanical Problems to prove that in all animal motion

there must be some quiescent fulcrum; and finds merit even in

Aristotle's ignorance. "Aristotle," he says[135], "did not know that

motion was produced by the muscle; and after staggering about from one

supposition to another, at last is compelled by the facts themselves

to recur to an innate spirit, which, he conceives, is contrasted, and

which pulls and pushes. And here we cannot help admiring the genius of

Aristotle, who, though ignorant of the muscle, invents something which

produces nearly the same effect as the muscle, namely, contraction and

pulling." He then, with great acuteness, points out the distinction

between Aristotle's opinions, thus favourably interpreted, and those of

Galen. In all this, we see something of the wish to find all truths in

the writings of the ancients, but nothing which materially interferes

with freedom of inquiry. The anatomists have in all ages and countries

been practically employed in seeking knowledge from observation. Facts

have ever been to them a subject of careful and profitable study; while

the ideas which enter into the wider truths of the science, are, as we

have seen, even still involved in obscurity, doubt, and contest.

5. _Maurolycus._--Francis Maurolycus of Messana, whose mathematical

works were published in 1575, was one of the great improvers of the

science of optics in his time. In his Preface to his Treatise on

the Spheres, he speaks of previous writers on the same subject; and

observes that as they have not superseded one another, they have not

rendered it unfit for any one to treat the subject afresh. "Yet," he

says, "it is impossible to amend the errors of all who have preceded

us. This would be a task too hard for Atlas, although he supports the

heavens. Even Copernicus is tolerated, who makes the sun to be fixed,

and the earth to move round it in a circle, and who is more worthy

of a whip or a scourge than of a refutation." The mathematicians and

astronomers of that time were not the persons most sensible of the

progress of physical knowledge; for the basis of their science, and

a great part of its substance, were contained in the writings of the

ancients; and till the time of Kepler, Ptolemy's work was, very justly,

looked upon as including all that was essential in the science.

6. _Benedetti._--But the writers on Mechanics were naturally led to

present themselves as innovators and experimenters; for all that the

ancients had taught concerning the doctrine of motion was erroneous;

while those who sought their knowledge from experiment, were constantly

led to new truths. John Baptist Benedetti, a Venetian nobleman, in

1599, published his _Speculationum Liber_, containing, among other

matter, a treatise on Mechanics, in which several of the Aristotelian

errors were refuted. In the Preface to this Treatise, he says, "Many

authors have written much, and with great ability, on Mechanics; but

since nature is constantly bringing to light something either new,

or before unnoticed, I too wished to put forth a few things hitherto

unattempted, or not sufficiently explained." In the doctrine of motion

he distinctly and at some length condemns and argues against all the

Aristotelian doctrines concerning motion, weight, and many other

fundamental principles of physics. Benedetti is also an adherent of

the Copernican doctrine. He states[136] the enormous velocity which

the heavenly bodies must have, if the earth be the centre of their

motions; and adds, "which difficulty does not occur according to the

beautiful theory of the Samian Aristarchus, expounded in a divine

manner by Nicolas Copernicus; against which the reasons alleged by

Aristotle are of no weight." Benedetti throughout shows no want of the

courage or ability which were needed in order to rise in opposition

against the dogmas of the Peripatetics. He does not, however, refer to

experiment in a very direct manner; indeed most of the facts on which

the elementary truths of mechanics rest, were known and admitted by the

Aristotelians; and therefore could not be adduced as novelties. On the

contrary, he begins with _à priori_ maxims, which experience would not

have confirmed. "Since," he says[137], "we have undertaken the task

of proving that Aristotle is wrong in his opinions concerning motion,

there are certain absolute truths, the objects of the intellect known

of themselves, which we must lay down in the first place." And then, as

an example of these truths, he states this: "Any two bodies of equal

size and figure, but of different materials, will have their natural

velocities in the same proportion as their weights;" where by their

natural velocities, he means the velocities with which they naturally

fall downwards.

7. _Gilbert._--The greatest of these practical reformers of science

is our countryman, William Gilbert; if, indeed, in virtue of the

clear views of the prospects which were then opening to science,

and of the methods by which her future progress was to be secured,

while he exemplified those views by physical discoveries, he does not

rather deserve the still higher praise of being at the same time a

theoretical and a practical reformer. Gilbert's physical researches

and speculations were employed principally upon subjects on which the

ancients had known little or nothing; and on which therefore it could

not be doubtful whether tradition or observation was the source of

knowledge. Such was magnetism; for the ancients were barely acquainted

with the attractive property of the magnet. Its polarity, including

repulsion as well as attraction, its direction towards the north,

its limited variation from this direction, its declination from the

horizontal position, were all modern discoveries. Gilbert's work[138]

on the magnet and on the magnetism of the earth, appeared in 1600;

and in this, he repeatedly maintains the superiority of experimental

knowledge over the physical philosophy of the ancients. His preface

opens thus: "Since in making discoveries and searching out the hidden

causes of things, stronger reasons are obtained from trustworthy

experiments and demonstrable arguments, than from probable conjectures

and the dogmas of those who philosophize in the usual manner," he has,

he says, "endeavoured to proceed from common magnetical experiments to

the inward constitution of the earth." As I have stated in the History

of Magnetism[139], Gilbert's work contains all the fundamental facts

of that science, so fully stated, that we have, at this day, little to

add to them. He is not, however, by the advance which he thus made,

led to depreciate the ancients, but only to claim for himself the same

liberty of philosophizing which they had enjoyed[140]. "To those

ancient and first parents of philosophy, Aristotle, Theophrastus,

Ptolemy, Hippocrates, Galen, be all due honour; from them it was that

the stream of wisdom has been derived down to posterity. But our age

has discovered and brought to light many things which they, if they

were yet alive, would gladly embrace. Wherefore we also shall not

hesitate to expound, by probable hypotheses, those things which by long

experience we have ascertained."

In this work the author not only adopts the Copernican doctrine of the

earth's motion, but speaks[141] of the contrary supposition as utterly

absurd, founding his argument mainly on the vast velocities which such

a supposition requires us to ascribe to the celestial bodies. Dr.

Gilbert was physician to Queen Elizabeth and to James the First, and

died in 1603. Some time after his death the executors of his brother

published another work of his, _De Mundo nostro Sublunari Philosophia

Nova_, in which similar views are still more comprehensively presented.

In this he says, "The two lords of philosophy, Aristotle and Galen,

are held in worship like gods, and rule the schools;--the former by

some destiny obtained a sway and influence among philosophers, like

that of his pupil Alexander among the kings of the earth;--Galen, with

like success, holds his triumph among the physicians of Europe." This

comparison of Aristotle to Alexander was also taken hold of by Bacon.

Nor is Gilbert an unworthy precursor of Bacon in the view he gives of

the History of Science, which occupies the first three chapters of his

Philosophy. He traces this history from "the simplicity and ignorance

of the ancients," through "the fabrication of the fable of the four

elements," to Aristotle and Galen. He mentions with due disapproval the

host of commentators which succeeded, the alchemists, the "shipwreck

of science in the deluge of the Goths," and the revival of letters

and genius in the time of "our grandfathers." "This later age," he

says, "has exploded the Barbarians, and restored the Greeks and Latins

to their pristine grace and honour. It remains, that if they have

written aught in error, this should be remedied by better and more

productive processes (_frugiferis_ institutis), not to be contemned

for their novelty; (for nothing which is true is really new, but is

perfect from eternity, though to weak man it may be unknown;) and that

thus Philosophy may bear her fruit." The reader of Bacon will not fail

to recognize, in these references to "fruit-bearing" knowledge, a

similarity of expression with the _Novum Organon_.

Bacon does not appear to me to have done justice to his contemporary.

He nowhere recognizes in the labours of Gilbert a community of

purpose and spirit with his own. On the other hand, he casts upon

him a reflection which he by no means deserves. In the _Advancement

of Learning_[142], he says, "Another error is, that men have used to

infect their meditations, opinions, and doctrines, with some conceits

which they have most admired, or some sciences to which they have

most applied; and given all things else a tincture according to

them, utterly untrue and improper.... So have the alchemists made a

philosophy out of a few experiments of the furnace; and Gilbertus,

our countryman, hath made a philosophy out of the observations of a

loadstone," (in the Latin, philosophiam etiam e magnete elicuit).

And in the same manner he mentions him in the _Novum Organon_[143],

as affording an example of an empirical kind of philosophy, which

appears to those daily conversant with the experiments, probable, but

to other persons incredible and empty. But instead of blaming Gilbert

for disturbing and narrowing science by a too constant reference to

magnetical rules, we might rather censure Bacon, for not seeing how

important in all natural philosophy are those laws of attraction

and repulsion of which magnetical phenomena are the most obvious

illustration. We may find ground for such a judgment in another passage

in which Bacon speaks of Gilbert. In the Second Book[144] of the _Novum

Organon_, having classified motions, he gives, as one kind, what he

calls, in his figurative language, _motion for gain_, or _motion of

need_, by which a body shuns heterogeneous, and seeks cognate bodies.

And he adds, "The Electrical operation, concerning which Gilbert and

others since him have made up such a wonderful story, is nothing less

than the appetite of a body, which, excited by friction, does not well

tolerate the air, and prefers another tangible body if it be found

near." Bacon's notion of an appetite in the body is certainly much

less philosophical than Gilbert's, who speaks of light bodies as drawn

towards amber by certain material radii[145]; and we might perhaps

venture to say that Bacon here manifests a want of clear mechanical

ideas. Bacon, too, showed his inferior aptitude for physical research

in rejecting the Copernican doctrine which Gilbert adopted. In the

_Advancement of Learning_[146], suggesting a history of the opinions

of philosophers, he says that he would have inserted in it even recent

theories, as those of Paracelsus; of Telesius, who restored the

philosophy of Parmenides; or Patricius, who resublimed the fumes of

Platonism; or Gilbert, who brought back the dogmas of Philolaus. But

Bacon quotes[147] with pleasure Gilbert's ridicule of the Peripatetics'

definition of heat. They had said, that heat is that which separates

heterogeneous and unites homogeneous matter; which, said Gilbert, is

as if any one were to define _man_ as that which sows wheat and plants

vines.

Galileo, another of Gilbert's distinguished contemporaries, had a

higher opinion of him. He says[148], "I extremely admire and envy this

author. I think him worthy of the greatest praise for the many new and

true observations which he has made, to the disgrace of so many vain

and fabling authors; who write, not from their own knowledge only,

but repeat everything they hear from the foolish and vulgar, without

attempting to satisfy themselves of the same by experience; perhaps

that they may not diminish the size of their books."

8. _Galileo._--Galileo was content with the active and successful

practice of experimental inquiry; and did not demand that such

researches should be made expressly subservient to that wider and

more ambitious philosophy, on which the author of the _Novum Organon_

employed his powers. But still it now becomes our business to trace

those portions of Galileo's views which have reference to the theory,

as well as the practice, of scientific investigation. On this subject,

Galileo did not think more profoundly, perhaps, than several of his

contemporaries; but in the liveliness of expression and illustration

with which he recommended his opinions on such topics, he was

unrivalled. Writing in the language of the people, in the attractive

form of dialogue, with clearness, grace, and wit, he did far more than

any of his predecessors had done to render the new methods, results,

and prospects of science familiar to a wide circle of readers, first

in Italy, and soon, all over Europe. The principal points inculcated

by him were already becoming familiar to men of active and inquiring

minds; such as,--that knowledge was to be sought from observation, and

not from books;--that it was absurd to adhere to, and debate about,

the physical tenets of Aristotle and the rest of the ancients. On

persons who followed this latter course, Galileo fixed the epithet of

Paper Philosophers[149]; because, as he wrote in a letter to Kepler,

this sort of men fancied that philosophy was to be studied like the

_Æneid_ or _Odyssey_, and that the true reading of nature was to be

detected by the collation of texts. Nothing so much shook the authority

of the received system of Physics as the experimental discoveries,

directly contradicting it, which Galileo made. By experiment, as I

have elsewhere stated[150], he disproved the Aristotelian doctrine that

bodies fall quickly or slowly in proportion to their weight. And when

he had invented the telescope, a number of new discoveries of the most

striking kind (the inequalities of the moon's surface, the spots in

the sun, the moon-like phases of Venus, the satellites of Jupiter, the

ring of Saturn,) showed, by the evidence of the eyes, how inadequate

were the conceptions, and how erroneous the doctrines of the ancients,

respecting the constitution of the universe. How severe the blow was to

the disciples of the ancient schools, we may judge by the extraordinary

forms of defence in which they tried to intrench themselves. They would

not look through Galileo's glasses; they maintained that what was seen

was an illusion of witchcraft; and they tried, as Galileo says[151],

with logical arguments, as if with magical incantations, to charm the

new planets out of the sky. No one could be better fitted than Galileo

for such a warfare. His great knowledge, clear intellect, gaiety, and

light irony, (with the advantage of being in the right,) enabled him to

play with his adversaries as he pleased. Thus when an Aristotelian[152]

rejected the discovery of the irregularities in the moon's surface,

because, according to the ancient doctrine, her form was a perfect

sphere, and held that the apparent cavities were filled with an

invisible crystal substance, Galileo replied, that he had no objection

to assent to this, but that then he should require his adversary in

return to believe that there were on the same surface invisible crystal

mountains ten times as high as those visible ones which he had actually

observed and measured.

We find in Galileo many thoughts which have since become established

maxims of modern philosophy. "Philosophy," he says[153], "is written

in that great book, I mean the Universe, which is constantly open

before our eyes; but it cannot be understood, unless we first know the

language and learn the characters in which it is written." With this

thought he combines some other lively images. One of his interlocutors

says concerning another, "Sarsi perhaps thinks that philosophy is

a book made up of the fancies of men, like the _Iliad_ or _Orlando

Furioso_, in which the matter of least importance is, that what is

written be true." And again, with regard to the system of authority, he

says, "I think I discover in him a firm belief that, in philosophizing,

it is necessary to lean upon the opinion of some celebrated author;

as if our mind must necessarily remain unfruitful and barren till it

be married to another man's reason."--"No," he says, "the case is not

so.--When we have the decrees of Nature, authority goes for nothing;

reason is absolute[154]."

In the course of Galileo's controversies, questions of the logic of

science came under discussion. Vincenzio di Grazia objected to a proof

from induction which Galileo adduced, because _all_ the particulars

were not enumerated; to which the latter justly replies[155], that

if induction were required to pass through all the cases, it would

be either useless or impossible;--impossible when the cases are

innumerable; useless when they have each already been verified, since

then the general proposition adds nothing to our knowledge.

One of the most novel of the characters which Science assumes in

Galileo's hands is, that she becomes cautious. She not only proceeds

leaning upon Experience, but she is content to proceed a little way

at a time. She already begins to perceive that she must rise to the

heights of knowledge by many small and separate steps. The philosopher

is desirous to know much, but resigned to be ignorant for a time of

that which cannot yet be known. Thus when Galileo discovered the true

law of the motion of a falling body[156], that the velocity increases

proportionally to the time from the beginning of the fall, he did

not insist upon immediately assigning the cause of this law. "The

cause of the acceleration of the motions of falling bodies is not,"

he says, "a necessary part of the investigation." Yet the conception

of this acceleration, as the result of the continued action of the

force of gravity upon the falling body, could hardly fail to suggest

itself to one who had formed the idea of force. In like manner, the

truth that the velocities, acquired by bodies falling down planes of

equal heights, are all equal, was known to Galileo and his disciples,

long before he accounted for it[157], by the principle, apparently

so obvious, that the momentum generated is as the moving force which

generates it. He was not tempted to rush at once, from an experimental

truth to a universal system. Science had learnt that she must move step

by step; and the gravity of her pace already indicated her approaching

maturity and her consciousness of the long path which lay before her.

But besides the genuine philosophical prudence which thus withheld

Galileo from leaping hastily from one inference to another, he had

perhaps a preponderating inclination towards facts; and did not feel,

so much as some other persons of his time, the need of reducing them to

ideas. He could bear to contemplate laws of motion without being urged

by an uncontrollable desire to refer them to conceptions of force.

9. _Kepler._--In this respect his friend Kepler differed from him;

for Kepler was restless and unsatisfied till he had reduced facts to

laws, and laws to causes; and never acquiesced in ignorance, though

he tested with the most rigorous scrutiny that which presented itself

in the shape of knowledge to fill the void. It may be seen in the

History of Astronomy[158] with what perseverance, energy, and fertility

of invention, Kepler pursued his labours, (enlivened and relieved by

the most curious freaks of fancy,) with a view of discovering the

rules which regulate the motions of the planet Mars. He represents

this employment under the image of a warfare; and describes[159] his

object to be "to triumph over Mars, and to prepare for him, as for one

altogether vanquished, tabular prisons and equated eccentric fetters;"

and when, "the enemy, left at home a despised captive, had burst all

the chains of the equations, and broken forth of the prisons of the

tables;"--when "it was buzzed here and there that the victory is vain,

and that the war is raging anew as violently as before;"--that is, when

the rules which he had proposed did not coincide with the facts;--he

by no means desisted from his attempts, but "suddenly sent into the

field a reserve of new physical reasonings on the rout and dispersion

of the veterans," that is, tried new suppositions suggested by such

views as he then entertained of the celestial motions. His efforts

to obtain the formal laws of the planetary motions resulted in some

of the most important discoveries ever made in astronomy; and if his

physical reasonings were for the time fruitless, this arose only from

the want of that discipline in mechanical ideas which the minds of

mathematicians had still to undergo; for the great discoveries of

Newton in the next generation showed that, in reality, the next step

of the advance was in this direction. Among all Kepler's fantastical

expressions, the fundamental thoughts were sound and true; namely,

that it was his business, as a physical investigator, to discover a

mathematical rule which governed and included all the special facts;

and that the rules of the motions of the planets must conform to some

conception of causation.

The same characteristics,--the conviction of rule and cause,

perseverance in seeking these, inventiveness in devising hypotheses,

love of truth in trying and rejecting them, and a lively Fancy playing

with the Reason without interrupting her,--appear also in his work

on Optics; in which he tried to discover the exact law of optical

refraction[160]. In this undertaking he did not succeed entirely;

nor does he profess to have done so. He ends his numerous attempts by

saying, "Now, reader, you and I have been detained sufficiently long

while I have been attempting to _collect into one fagot_ the measures

of different refractions."

In this and in other expressions, we see how clearly he apprehended

that _colligation of facts_ which is the main business of the practical

discoverer. And by his peculiar endowments and habits, Kepler exhibits

an essential portion of this process, which hardly appears at all in

Galileo. In order to bind together facts, theory is requisite as well

as observation,--the cord as well as the fagots. And the true theory

is often, if not always, obtained by trying several and selecting the

right. Now of this portion of the discoverer's exertions, Kepler is

a most conspicuous example. His fertility in devising suppositions,

his undaunted industry in calculating the results of them, his entire

honesty and candour in resigning them if these results disagreed with

the facts, are a very instructive spectacle; and are fortunately

exhibited to us in the most lively manner in his own garrulous

narratives. Galileo urged men by precept as well as example to begin

their philosophy from observation; Kepler taught them by his practice

that they must proceed from observation by means of hypotheses. The

one insisted upon facts; the other dealt no less copiously with ideas.

In the practical, as in the speculative portion of our history, this

antithesis shows itself; although in the practical part we cannot have

the two elements separated, as in the speculative we sometimes have.

In the _History of Science_[161], I have devoted several pages to the

intellectual character of Kepler, inasmuch as his habit of devising so

great a multitude of hypotheses, so fancifully expressed, had led some

writers to look upon him as an inquirer who transgressed the most fixed

rules of philosophical inquiry. This opinion has arisen, I conceive,

among those who have forgotten the necessity of Ideas as well as Facts

for all theory; or who have overlooked the impossibility of selecting

and explicating our ideas without a good deal of spontaneous play of

the mind. It must, however, always be recollected that Kepler's genius

and fancy derived all their scientific value from his genuine and

unmingled love of truth. These qualities appeared, not only in the

judgment he passed upon hypotheses, but also in matters which more

immediately concerned his reputation. Thus when Galileo's discovery of

the telescope disproved several opinions which Kepler had published

and strenuously maintained, he did not hesitate a moment to retract

his assertions and range himself by the side of Galileo, whom he

vigorously supported in his warfare against those who were incapable of

thus cheerfully acknowledging the triumph of new facts over their old

theories.

10. _Tycho._--There remains one eminent astronomer, the friend and

fellow-labourer of Kepler, whom we must not separate from him as one

of the practical reformers of science. I speak of Tycho Brahe, who is,

I think, not justly appreciated by the literary world in general, in

consequence of his having made a retrograde step in that portion of

astronomical theory which is most familiar to the popular mind. Though

he adopted the Copernican view of the motion of the planets about the

sun, he refused to acknowledge the annual and diurnal motion of the

earth. But notwithstanding this mistake, into which he was led by his

interpretation of Scripture rather than of nature, Tycho must ever be

one of the greatest names in astronomy. In the philosophy of science

also, the influence of what he did is far from inconsiderable; and

especially its value in bringing into notice these two points:--that

not only are observations the beginning of science, but that the

progress of science may often depend upon the observer's pursuing his

task regularly and carefully for a long time, and with well devised

instruments; and again, that observed facts offer a _succession_ of

laws which we discover as our observations become better, and as our

theories are better adapted to the observations. With regard to the

former point, Tycho's observatory was far superior to all that had

preceded it[162], not only in the optical, but in the mechanical

arrangements; a matter of almost equal consequence. And hence it was

that his observations inspired in Kepler that confidence which led him

to all his labours and all his discoveries. "Since," he says[163], "the

divine goodness has given us in Tycho Brahe an exact observer, from

whose observations this error of eight minutes in the calculations of

the Ptolemaic hypothesis is detected, let us acknowledge and make use

of this gift of God: and since this error cannot be neglected, these

eight minutes alone have prepared the way for an entire reform of

Astronomy, and are to be the main subject of this work."

With regard to Tycho's discoveries respecting the moon, it is to be

recollected that besides the first inequality of the moon's motion,

(the _equation of the centre_, arising from the elliptical form of her

orbit,) Ptolemy had discovered a second inequality, the _evection_,

which, as we have observed in the History of this subject[164], might

have naturally suggested the suspicion that there were still other

inequalities. In the middle ages, however, such suggestions, implying

a constant progress in science, were little attended to; and, we have

seen, that when an Arabian astronomer[165] had really discovered

another inequality of the moon, it was soon forgotten, because it had

no place in the established systems. Tycho not only rediscovered the

lunar inequality, (the _variation_,) thus once before won and lost, but

also two other inequalities; namely[166], the _change of inclination_

of the moon's orbit as the line of nodes moves round, and an inequality

in the motion of the line of nodes. Thus, as I have elsewhere said,

it appeared that the discovery of a rule is a step to the discovery

of deviations from that rule, which require to be expressed in other

rules. It became manifest to astronomers, and through them to all

philosophers, that in the application of theory to observation, we

find, not only the stated phenomena, for which the theory does account,

but also _residual phenomena_, which are unaccounted for, and remain

over and above the calculation. And it was seen further, that these

residual phenomena might be, altogether or in part, exhausted by new

theories.

These were valuable lessons; and the more valuable inasmuch as men

were now trying to lay down maxims and methods for the conduct of

science. A revolution was not only at hand, but had really taken place,

in the great body of real cultivators of science. The occasion now

required that this revolution should be formally recognized;--that

the new intellectual power should be clothed with the forms of

government;--that the new philosophical republic should be acknowledged

as a sister state by the ancient dynasties of Aristotle and Plato.

There was needed some great Theoretical Reformer, to speak in the name

of the Experimental Philosophy; to lay before the world a declaration

of its rights and a scheme of its laws. And thus our eyes are turned to

Francis Bacon, and others who like him attempted this great office. We

quit those august and venerable names of discoverers, whose appearance

was the prelude and announcement of the new state of things then

opening; and in doing so, we may apply to them the language which Bacon

applies to himself[167]:--

Χαίρετε Κήρυκες Διὸ ς ἄγγελοι ἠδὲ καὶ ἀνδρῶν.

Hail, Heralds, Messengers of Gods and Men!

FOOTNOTES:

[Footnote 128: His works have never been published, and exist in

manuscript in the library of the Institute at Paris. Some extracts were

published by Venturi, _Essai sur les Ouvrages de Leonard da Vinci_.

Paris, 1797.]

[Footnote 129: Leonardo died in 1520, at the age of 78.]

[Footnote 130: Paul III. in 1543.]

[Footnote 131: _Hist. Ind. Sc._ b. v. c. ii.]

[Footnote 132: Born 1537, died 1619.]

[Footnote 133: _Hist. Ind. Sc._ b. xvii. c. ii. sect. 1.]

[Footnote 134: Fabricius, _De Motu Locali_, p. 182.]

[Footnote 135: p. 199.]

[Footnote 136: _Speculationum Liber_, p. 195.]

[Footnote 137: _Ibid._ p. 169.]

[Footnote 138: Gulielmi Gilberti, _Colcestriensis, Medici Londinensis,

De Magnete, Magneticisque Corporibus, et de Magno Magnete Tellure,

Physiologia Nova, plurimis et Argumentis et Experimentis demonstrata_.]

[Footnote 139: _Hist. Ind. Sc._ b. xii. c. i.]

[Footnote 140: Pref.]

[Footnote 141: _De Magnete_, lib. vi. c. 3, 4.]

[Footnote 142: _Nov. Org._ b. i.]

[Footnote 143: B. i. Aph. 64.]

[Footnote 144: Vol. ix. 185.]

[Footnote 145: _De Magnete_, p. 60.]

[Footnote 146: B. iii. c. 4.]

[Footnote 147: _Nov. Org._ b. ii. Aph. 48.]

[Footnote 148: Drinkwater's _Life of Galileo_, p. 18.]

[Footnote 149: _Life of Galileo_, p. 9.]

[Footnote 150: _Hist. Ind. Sc._ b. vi. c. ii. sect. 5.]

[Footnote 151: _Life of Galileo_, p. 29.]

[Footnote 152: _Ibid._ p. 33.]

[Footnote 153: _Il Saggiatore_, ii. 247.]

[Footnote 154: _Il Saggiatore_, ii. 200.]

[Footnote 155: _Ibid._ i. 501.]

[Footnote 156: _Hist. Ind. Sc._ b. vi. c. ii. sect. 2.]

[Footnote 157: _Hist. Ind. Sc._ b. vi. c. ii. sect. 4.]

[Footnote 158: _Ibid._ b. v. c. iv. sect. 1.]

[Footnote 159: _De Stell. Mart._ p. iv. c. 51 (1609); Drinkwater's

_Kepler_, p. 33.]

[Footnote 160: Published 1604. _Hist. Ind. Sc._ b. ix. c. ii.]

[Footnote 161: _Hist. Ind. Sc._ b. v. c. iv. sect. 1.]

[Footnote 162: _Hist. Ind. Sc._ b. vii. c. vi. sect 1.]

[Footnote 163: _De Stell. Mart._ p. 11. c. 19.]

[Footnote 164: _Hist. Ind. Sc._ b. ii. c. iv. sect. 6.]

[Footnote 165: _Ibid._ sect. 8.]

[Footnote 166: Montucla, i. 566.]

[Footnote 167: _De Augm._ lib. iv. c. 1.]

CHAPTER XV.

FRANCIS BACON.

(I.) 1. _General Remarks._--It is a matter of some difficulty to speak

of the character and merits of this illustrious man, as regards his

place in that philosophical history with which we are here engaged.

If we were to content ourselves with estimating him according to the

office which, as we have just seen, he claims for himself[168], as

merely the harbinger and announcer of a sounder method of scientific

inquiry than that which was recognized before him, the task would

be comparatively easy. For we might select from his writings those

passages in which he has delivered opinions and pointed out processes,

then novel and strange, but since confirmed by the experience of

actual discoverers, and by the judgments of the wisest of succeeding

philosophers; and we might pass by, without disrespect, but without

notice, maxims and proposals which have not been found available for

use;--views so indistinct and vague, that we are even yet unable to

pronounce upon their justice;--and boundless anticipations, dictated

by the sanguine hopes of a noble and comprehensive intellect. But

if we thus reduce the philosophy of Bacon to that portion which the

subsequent progress of science has rigorously verified, we shall

have to pass over many of those declarations which have excited

most notice in his writings, and shall lose sight of many of those

striking thoughts which his admirers most love to dwell upon. For he

is usually spoken of, at least in this country, as a teacher who

not only commenced, but in a great measure completed, the Philosophy

of Induction. He is considered, not only as having asserted some

general principles, but laid down the special rules of scientific

investigation; as not only one of the Founders, but the supreme

Legislator of the modern Republic of Science; not only the Hercules who

slew the monsters that obstructed the earlier traveller, but the Solon

who established a constitution fitted for all future time.

2. Nor is it our purpose to deny that of such praise he deserves

a share which, considering the period at which he lived, is truly

astonishing. But it is necessary for us in this place to discriminate

and select that portion of his system which, bearing upon _physical_

science, has since been confirmed by the actual history of science.

Many of Bacon's most impressive and captivating passages contemplate

the extension of the new methods of discovering truth to intellectual,

to moral, to political, as well as to physical science. And how far,

and how, the advantages of the inductive method may be secured for

those important branches of speculation, it will at some future time

be a highly interesting task to examine. But our plan requires us at

present to omit the consideration of these; for our purpose is to learn

what the genuine course of the formation of science is, by tracing it

in those portions of human knowledge, which, by the confession of all,

are most exact, most certain, most complete. Hence we must here deny

ourselves the dignity and interest which float about all speculations

in which the great moral and political concerns of men are involved.

It cannot be doubted that the commanding position which Bacon occupies

in men's estimation arises from his proclaiming a reform in philosophy

of so comprehensive a nature;--a reform which was to infuse a new

spirit into every part of knowledge. Physical Science has tranquilly

and noiselessly adopted many of his suggestions; which were, indeed,

her own natural impulses, not borrowed from him; and she is too deeply

and satisfactorily absorbed in contemplating her results, to talk much

about the methods of obtaining them which she has thus instinctively

pursued. But the philosophy which deals with mind, with manners,

with morals, with polity, is conscious still of much obscurity and

perplexity; and would gladly borrow aid from a system in which aid

is so confidently promised. The aphorisms and phrases of the _Novum

Organon_ are far more frequently quoted by metaphysical, ethical, and

even theological writers, than they are by the authors of works on

physics.

3. Again, even as regards physics, Bacon's fame rests upon something

besides the novelty of the maxims which he promulgated. That a

revolution in the method of scientific research was going on, all

the greatest physical investigators of the sixteenth century were

fully aware, as we have shown in the last chapter. But their writings

conveyed this conviction to the public at large somewhat slowly. Men of

letters, men of the world, men of rank, did not become familiar with

the abstruse works in which these views were published; and above all,

they did not, by such occasional glimpses as they took of the state of

physical science, become aware of the magnitude and consequences of

this change. But Bacon's lofty eloquence, wide learning, comprehensive

views, bold pictures of the coming state of things, were fitted to

make men turn a far more general and earnest gaze upon the passing

change. When a man of his acquirements, of his talents, of his rank and

position, of his gravity and caution, poured forth the strongest and

loftiest expressions and images which his mind could supply, in order

to depict the "Great Instauration" which he announced;--in order to

contrast the weakness, the blindness, the ignorance, the wretchedness,

under which men had laboured while they followed the long beaten track,

with the light, the power, the privileges, which they were to find in

the paths to which he pointed;--it was impossible that readers of all

classes should not have their attention arrested, their minds stirred,

their hopes warmed; and should not listen with wonder and with pleasure

to the strains of prophetic eloquence in which so great a subject

was presented. And when it was found that the prophecy was verified;

when it appeared that an immense change in the methods of scientific

research really _had_ occurred;--that vast additions to man's knowledge

and power had been acquired, in modes like those which had been spoken

of;--that further advances might be constantly looked for;--and that a

progress, seemingly boundless, was going on in the direction in which

the seer had thus pointed;--it was natural that men should hail him as

the leader of the revolution; that they should identify him with the

event which he was the first to announce; that they should look upon

him as the author of that which he had, as they perceived, so soon and

so thoroughly comprehended.

4. For we must remark, that although (as we have seen) he was not the

only, nor the earliest writer, who declared that the time was come

for such a change, he not only proclaimed it more emphatically, but

understood it, in its general character, much more exactly, than any

of his contemporaries. Among the maxims, suggestions and anticipations

which he threw out, there were many of which the wisdom and the novelty

were alike striking to his immediate successors;--there are many

which even now, from time to time, we find fresh reason to admire,

for their acuteness and justice. Bacon stands far above the herd of

loose and visionary speculators who, before and about his time, spoke

of the establishment of new philosophies. If we must select some one

philosopher as the Hero of the revolution in scientific method, beyond

all doubt Francis Bacon must occupy the place of honour.

We shall, however, no longer dwell upon these general considerations,

but shall proceed to notice some of the more peculiar and

characteristic features of Bacon's philosophy; and especially those

views, which, occurring for the first time in his writings, have been

fully illustrated and confirmed by the subsequent progress of science,

and have become a portion of the permanent philosophy of our times.

(II.) 5. _A New Era announced._--The first great feature which

strikes us in Bacon's philosophical views is that which we have

already noticed;--his confident and emphatic announcement of a _New

Era_ in the progress of science, compared with which the advances of

former times were poor and trifling. This was with Bacon no loose and

shallow opinion, taken up on light grounds and involving only vague,

general notions. He had satisfied himself of the justice of such a

view by a laborious course of research and reflection. In 1605, at the

age of forty-four, he published his Treatise of the _Advancement of

Learning_, in which he takes a comprehensive and spirited survey of

the condition of all branches of knowledge which had been cultivated

up to that time. This work was composed with a view to that reform

of the existing philosophy which Bacon always had before his eyes;

and in the Latin edition of his works, forms the First Part of the

_Instauratio Magna_. In the Second Part of the Instauratio, the _Novum

Organon_, published in 1620, he more explicitly and confidently states

his expectations on this subject. He points out how slightly and

feebly the examination of nature had been pursued up to his time, and

with what scanty fruit. He notes the indications of this in the very

limited knowledge of the Greeks who had till then been the teachers

of Europe, in the complaints of authors concerning the subtilty and

obscurity of the secrets of nature, in the dissensions of sects, in

the absence of useful inventions resulting from theory, in the fixed

form which the sciences had retained for two thousand years. Nor, he

adds[169], is this wonderful; for how little of his thought and labour

has man bestowed upon science! Out of twenty-five centuries scarce six

have been favourable to the progress of knowledge. And even in those

favoured times, natural philosophy received the smallest share of man's

attention; while the portion so given was marred by controversy and

dogmatism; and even those who have bestowed a little thought upon

this philosophy, have never made it their main study, but have used it

as a passage or drawbridge to serve other objects. And thus, he says,

the great Mother of the Sciences is thrust down with indignity to the

offices of a handmaid; is made to minister to the labours of medicine

or mathematics, or to give the first preparatory tinge to the immature

minds of youth. For these and similar considerations of the errors of

past time, he draws hope for the future, employing the same argument

which Demosthenes uses to the Athenians: "That which is worst in the

events of the past, is the best as a ground of trust in the future.

For if you had done all that became you, and still had been in this

condition, your case might be desperate; but since your failure is the

result of your own mistakes, there is good hope that, correcting the

error of your course, you may reach a prosperity yet unknown to you."

(III.) 6. _A change of existing Method._--All Bacon's hope of

improvement indeed was placed in an entire _change of the Method_ by

which science was pursued; and the boldness, and at the same time (the

then existing state of science being considered), the definiteness of

his views of the change that was requisite, are truly remarkable.

That all knowledge must begin with observation, is one great principle

of Bacon's philosophy; but I hardly think it necessary to notice the

inculcation of this maxim as one of his main services to the cause of

sound knowledge, since it had, as we have seen, been fully insisted

upon by others before him, and was growing rapidly into general

acceptance without his aid. But if he was not the first to tell men

that they must collect their knowledge from observation, he had no

rival in his peculiar office of teaching them _how_ science must thus

be gathered from experience.

It appears to me that by far the most extraordinary parts of Bacon's

works are those in which, with extreme earnestness and clearness, he

insists upon a _graduated and successive induction_, as opposed to a

hasty transit from special facts to the highest generalizations. The

nineteenth Axiom of the First Book of the _Novum Organon_ contains a

view of the nature of true science most exact and profound, and, so

far as I am aware, at the time perfectly new. "There are two ways, and

can only be two, of seeking and finding truth. The one, from sense and

particulars, takes a flight to the most general axioms, and from those

principles and their truth, settled once for all, invents and judges of

intermediate axioms. The other method collects axioms from sense and

particulars, ascending _continuously and by degrees_, so that in the

end it arrives at the most general axioms; this latter way is the true

one, but hitherto untried."

It is to be remarked, that in this passage Bacon employs the term

_axioms_ to express any propositions collected from facts by induction,

and thus fitted to become the starting-point of deductive reasonings.

How far propositions so obtained may approach to the character of

axioms in the more rigorous sense of the term, we have already in some

measure examined; but that question does not here immediately concern

us. The truly remarkable circumstance is to find this recommendation

of a continuous advance from observation, by limited steps, through

successive gradations of generality, given at a time when speculative

men in general had only just begun to perceive that they must begin

their course from experience in some way or other. How exactly this

description represents the general structure of the soundest and

most comprehensive physical theories, all persons who have studied

the progress of science up to modern times can bear testimony; but

perhaps this structure of science cannot in any other way be made so

apparent as by those Tables of successive generalizations in which we

have exhibited the history and constitution of some of the principal

physical sciences, in the Chapter of a preceding work which treats of

the Logic of Induction. And the view which Bacon thus took of the true

progress of science was not only new, but, so far as I am aware, has

never been adequately illustrated up to the present day.

7. It is true, as I observed in the last chapter, that Galileo had been

led to see the necessity, not only of proceeding from experience in the

pursuit of knowledge, but of proceeding cautiously and gradually; and

he had exemplified this rule more than once, when, having made one step

in discovery, he held back his foot, for a time, from the next step,

however tempting. But Galileo had not reached this wide and commanding

view of the successive subordination of many steps, all leading up at

last to some wide and simple general truth. In catching sight of this

principle, and in ascribing to it its due importance, Bacon's sagacity,

so far as I am aware, wrought unassisted and unrivalled.

8. Nor is there any wavering or vagueness in Bacon's assertion of this

important truth. He repeats it over and over again; illustrates it by

a great number of the most lively metaphors and emphatic expressions.

Thus he speaks of the successive _floors_ (_tabulata_) of induction;

and speaks of each science as a _pyramid_[170] which has observation

and experience for its basis. No images can better exhibit the relation

of general and particular truths, as our own Inductive Tables may serve

to show.

(IV.) 9. _Comparison of the New and Old Method._ Again; not less

remarkable is his contrasting this true Method of Science (while it was

almost, as he says, yet untried) with the ancient and _vicious Method_,

which began, indeed, with facts of observation, but rushed at once

and with no gradations, to the most general principles. For this was

the course which had been actually followed by all those speculative

reformers who had talked so loudly of the necessity of beginning our

philosophy from experience. All these men, if they attempted to frame

physical doctrines at all, had caught up a few facts of observation,

and had erected a universal theory upon the suggestions which these

offered. This process of illicit generalization, or, as Bacon terms

it, Anticipation of Nature (_anticipatio naturæ_), in opposition to

the Interpretation of Nature, he depicts with singular acuteness, in

its character and causes. "These two ways," he says[171], "both begin

from sense and particulars; but their discrepancy is immense. The one

merely skims over experience and particulars in a cursory transit; the

other deals with them in a due and orderly manner. The one, at its very

outset, frames certain general abstract principles, but useless; the

other gradually rises to those principles which have a real existence

in nature."

"The former path," he adds[172], "that of illicit and hasty

generalization, is one which the intellect follows when abandoned to

its own impulse; and this it does from the requisitions of logic. For

the mind has a yearning which makes it dart forth to generalities, that

it may have something to rest in; and after a little dallying with

experience, becomes weary of it; and all these evils are augmented by

logic, which requires these generalities to make a show with in its

disputations."

"In a sober, patient, grave intellect," he further adds, "the mind, by

its own impulse, (and more especially if it be not impelled by the sway

of established opinions) attempts in some measure that other and true

way, of gradual generalization; but this it does with small profit;

for the intellect, except it be regulated and aided, is a faculty of

unequal operation, and altogether unapt to master the obscurity of

things."

The profound and searching wisdom of these remarks appears more

and more, as we apply them to the various attempts which men have

made to obtain knowledge; when they begin with the contemplation of

a few facts, and pursue their speculations, as upon most subjects

they have hitherto generally done; for almost all such attempts have

led immediately to some process of illicit generalization, which

introduces an interminable course of controversy. In the physical

sciences, however, we have the further inestimable advantage of seeing

the other side of the contrast exemplified: for many of them, as our

inductive Tables show us, have gone on according to the most rigorous

conditions of gradual and successive generalization; and in consequence

of this circumstance in their constitution, possess, in each part of

their structure, a solid truth, which is always ready to stand the

severest tests of reasoning and experiment.

We see how justly and clearly Bacon judged concerning the mode in which

facts are to be employed in the construction of science. This, indeed,

has ever been deemed his great merit: insomuch that many persons appear

to apprehend the main substance of his doctrine to reside in the maxim

that facts of observation, and such facts alone, are the essential

elements of all true science.

(V.) 10. _Ideas are necessary._--Yet we have endeavoured to establish

the doctrine that facts are but one of two ingredients of knowledge

both equally necessary;--that _Ideas_ are no less indispensable than

facts themselves; and that except these be duly unfolded and applied,

facts are collected in vain. Has Bacon then neglected this great

portion of his subject? Has he been led by some partiality of view, or

some peculiarity of circumstances, to leave this curious and essential

element of science in its pristine obscurity? Was he unaware of its

interest and importance?

We may reply that Bacon's philosophy, in its effect upon his readers

in general, does _not_ give due weight or due attention to the ideal

element of our knowledge. He is considered as peculiarly and eminently

the asserter of the value of experiment and observation. He is always

understood to belong to the experiential, as opposed to the ideal

school. He is held up in contrast to Plato and others who love to dwell

upon that part of knowledge which has its origin in the intellect of

man.

11. Nor can it be denied that Bacon has, in the finished part of his

_Novum Organon_, put prominently forwards the necessary dependence of

all our knowledge upon Experience, and said little of its dependence,

equally necessary, upon the Conceptions which the intellect itself

supplies. It will appear, however, on a close examination, that he

was by no means insensible or careless of this internal element of

all connected speculation. He held the balance, with no partial or

feeble hand, between phenomena and ideas. He urged the Colligation of

Facts, but he was not the less aware of the value of the Explication of

Conceptions.

12. This appears plainly from some remarkable Aphorisms in the _Novum

Organon_. Thus, in noticing the causes of the little progress then

made by science[173], he states this:--"In the current Notions, all is

unsound, whether they be logical or physical. _Substance_, _quality_,

_action_, _passion_, even _being_, are not good Conceptions; still less

are _heavy_, _light_, _dense_, _rare_, _moist_, _dry_, _generation_,

_corruption_, _attraction_, _repulsion_, _element_, _matter_, _form_,

and others of that kind; all are fantastical and ill-defined." And in

his attempt to exemplify his own system, he hesitates[174] in accepting

or rejecting the notions of _elementary_, _celestial_, _rare_, as

belonging to fire, since, as he says, they are vague and ill-defined

notions (_notiones vagæ nec bene terminatæ_). In that part of his work

which appears to be completed, there is not, so far as I have noticed,

any attempt to fix and define any notions thus complained of as loose

and obscure. But yet such an undertaking appears to have formed part

of his plan; and in the _Abecedarium Naturæ_[175], which consists of

the heads of various portions of his great scheme, marked by letters

of the alphabet, we find the titles of a series of dissertations "On

the Conditions of Being," which must have had for their object the

elucidation of divers Notions essential to science, and which would

have been contributions to the Explication of Conceptions, such as

we have attempted in a former part of this work. Thus some of the

subjects of these dissertations are;--Of Much and Little;--Of Durable

and Transitory;--Of Natural and Monstrous;--Of Natural and Artificial.

When the philosopher of induction came to discuss these, considered as

_conditions of existence_, he could not do otherwise than develope,

limit, methodize, and define the Ideas involved in these Notions,

so as to make them consistent with themselves, and a fit basis of

demonstrative reasoning. His task would have been of the same nature

as ours has been, in that part of this work which treats of the

Fundamental Ideas of the various classes of sciences.

13. Thus Bacon, in his speculative philosophy, took firmly hold of

both the handles of science; and if he had completed his scheme, would

probably have given due attention to Ideas, no less than to Facts, as

an element of our knowledge; while in his view of the general method

of ascending from facts to principles, he displayed a sagacity truly

wonderful. But we cannot be surprised, that in attempting to exemplify

the method which he recommended, he should have failed. For the method

could be exemplified only by some important discovery in physical

science; and great discoveries, even with the most perfect methods, do

not come at command. Moreover, although the general structure of his

scheme was correct, the precise import of some of its details could

hardly be understood, till the actual progress of science had made men

somewhat familiar with the kind of steps which it included.

(VI.) 14. _Bacon's Example._--Accordingly, Bacon's _Inquisition into

the Nature of Heat_, which is given in the Second Book of the _Novum

Organon_ as an example of the mode of interrogating Nature, cannot be

looked upon otherwise than as a complete failure. This will be evident

if we consider that, although the exact nature of heat is still an

obscure and controverted matter, the science of Heat now consists of

many important truths; and that to none of these truths is there any

approximation in Bacon's essay. From his process he arrives at this,

as the "forma or true definition" of heat;--"that it is an expansive,

restrained motion, modified in certain ways, and exerted in the

smaller particles of the body." But the steps by which the science of

Heat really advanced were (as may be seen in the history[176] of the

subject) these;--The discovery of a _measure_ of heat or temperature

(the thermometer); the establishment of the _laws_ of conduction

and radiation; of the _laws_ of specific heat, latent heat, and the

like. Such steps have led to Ampère's _hypothesis_[177], that heat

consists in the vibrations of an imponderable fluid; and to Laplace's

_hypothesis_, that temperature consists in the internal radiation of

such a fluid. These hypotheses cannot yet be said to be even probable;

but at least they are so modified as to include some of the preceding

laws which are firmly established; whereas Bacon's hypothetical motion

includes no laws of phenomena, explains no process, and is indeed

itself an example of illicit generalization.

15. One main ground of Bacon's ill fortune in this undertaking appears

to be, that he was not aware of an important maxim of inductive

science, that we must first obtain the _measure_ and ascertain the

_laws_ of phenomena, before we endeavour to discover their _causes_.

The whole history of thermotics up to the present time has been

occupied with the _former_ step, and the task is not yet completed:

it is no wonder, therefore, that Bacon failed entirely, when he so

prematurely attempted the _second_. His sagacity had taught him that

the progress of science must be gradual; but it had not led him to

judge adequately how gradual it must be, nor of what different kinds

of inquiries, taken in due order, it must needs consist, in order to

obtain success.

Another mistake, which could not fail to render it unlikely that Bacon

should really exemplify his precepts by any actual advance in science,

was, that he did not justly appreciate the sagacity, the inventive

genius, which all discovery requires. He conceived that he could

supersede the necessity of such peculiar endowments. "Our method of

discovery in science," he says[178], "is of such a nature, that there

is not much left to acuteness and strength of genius, but all degrees

of genius and intellect are brought nearly to the same level." And he

illustrates this by comparing his method to a pair of compasses, by

means of which a person with no manual skill may draw a perfect circle.

In the same spirit he speaks of proceeding by _due rejections_; and

appears to imagine that when we have obtained a collection of facts, if

we go on successively rejecting what is false, we shall at last find

that we have, left in our hands, that scientific truth which we seek.

I need not observe how far this view is removed from the real state of

the case. The necessity of a _conception_ which must be furnished by

the mind in order to bind together the facts, could hardly have escaped

the eye of Bacon, if he had cultivated more carefully the ideal side

of his own philosophy. And any attempts which he could have made to

construct such conceptions by mere rule and method, must have ended

in convincing him that nothing but a peculiar inventive talent could

supply that which was thus not contained in the facts, and yet was

needed for the discovery.

(VII.) 16. _His Failure._--Since Bacon, with all his acuteness, had not

divined circumstances so important in the formation of science, it is

not wonderful that his attempt to reduce this process to a _Technical

Form_ is of little value. In the first place, he says[179], we must

prepare a natural and experimental history, good and sufficient; in the

next place, the instances thus collected are to be arranged in Tables

in some orderly way; and then we must apply a legitimate and true

induction. And in his example[180], he first collects a great number

of cases in which heat appears under various circumstances, which he

calls "a Muster of Instances before the intellect," (_comparentia

instantiarum ad intellectum_,) or a _Table of the Presence_ of the

thing sought. He then adds a _Table of its Absence_ in proximate cases,

containing instances where heat does not appear; then a _Table of

Degrees_, in which it appears with greater or less intensity. He then

adds[181], that we must try to exclude several obvious suppositions,

which he does by reference to some of the instances he has collected;

and this step he calls the _Exclusive_, or the _Rejection of Natures_.

He then observes, (and justly,) that whereas truth emerges more easily

from error than from confusion, we may, after this preparation, _give

play to the intellect_, (fiat permissio intellectus,) and make an

attempt at induction, liable afterwards to be corrected; and by this

step, which he terms his _First Vindemiation_, or _Inchoate Induction_,

he is led to the proposition concerning heat, which we have stated

above.

17. In all the details of his example he is unfortunate. By proposing

to himself to examine at once into the _nature_ of heat, instead

of the laws of special classes of phenomena, he makes, as we have

said, a fundamental mistake; which is the less surprising since he

had before him so few examples of the right course in the previous

history of science. But further, his collection of instances is very

loosely brought together; for he includes in his list the _hot_ taste

of aromatic plants, the _caustic_ effects of acids, and many other

facts which cannot be ascribed to heat without a studious laxity in

the use of the word. And when he comes to that point where he permits

his intellect its range, the conception of _motion_ upon which it at

once fastens, appears to be selected with little choice or skill, the

suggestion being taken from flame[182], boiling liquids, a blown fire,

and some other cases. If from such examples we could imagine heat

to be motion, we ought at least to have some gradation to cases of

heat where no motion is visible, as in a red-hot iron. It would seem

that, after a large collection of instances had been looked at, the

intellect, even in its first attempts, ought not to have dwelt upon

such an hypothesis as this.

18. After these steps, Bacon speaks of several classes of instances

which, singling them out of the general and indiscriminate collection

of facts, he terms _Instances with Prerogative_: and these he points

out as peculiar aids and guides to the intellect in its task. These

Instances with Prerogative have generally been much dwelt upon by those

who have commented on the _Novum Organon_. Yet, in reality, such a

classification, as has been observed by one of the ablest writers of

the present day[183], is of little service in the task of induction.

For the instances are, for the most part, classed, not according to

the ideas which they involve, or to any obvious circumstance in the

facts of which they consist, but according to the extent or manner of

their influence upon the inquiry in which they are employed. Thus we

have Solitary Instances, Migrating Instances, Ostensive Instances,

Clandestine Instances, so termed according to the degree in which

they exhibit, or seem to exhibit, the property whose nature we would

examine. We have Guide-Post Instances, (_Instantiæ Crucis_,) Instances

of the Parted Road, of the Doorway, of the Lamp, according to the

guidance they supply to our advance. Such a classification is much of

the same nature as if, having to teach the art of building, we were to

describe tools with reference to the amount and place of the work which

they must do, instead of pointing out their construction and use:--as

if we were to inform the pupil that we must have tools for lifting a

stone up, tools for moving it sideways, tools for laying it square,

tools for cementing it firmly. Such an enumeration of ends would convey

little instruction as to the means. Moreover, many of Bacon's classes

of instances are vitiated by the assumption that the "form," that is,

the general law and cause of the property which is the subject of

investigation, is to be looked for directly in the instances; which, as

we have seen in his inquiry concerning heat, is a fundamental error.

19. Yet his phraseology in some cases, as in the _instantia crucis_,

serves well to mark the place which certain experiments hold in our

reasonings: and many of the special examples which he gives are full

of acuteness and sagacity. Thus he suggests swinging a pendulum in a

mine, in order to determine whether the attraction of the earth arises

from the attraction of its parts; and observing the tide at the same

moment in different parts of the world, in order to ascertain whether

the motion of the water is expansive or progressive; with other

ingenious proposals. These marks of genius may serve to counterbalance

the unfavourable judgment of Bacon's aptitude for physical science

which we are sometimes tempted to form, in consequence of his false

views on other points; as his rejection of the Copernican system, and

his undervaluing Gilbert's magnetical speculations. Most of these

errors arose from a too ambitious habit of intellect, which would not

be contented with any except very wide and general truths; and from an

indistinctness of mechanical, and perhaps, in general, of mathematical

ideas:--defects which Bacon's own philosophy was directed to remedy,

and which, in the progress of time, it has remedied in others.

(VIII.) 20. _His Idols._--Having thus freely given our judgment

concerning the most exact and definite portion of Bacon's precepts,

it cannot be necessary for us to discuss at any length the value

of those more vague and general _Warnings_ against prejudice and

partiality, against intellectual indolence and presumption, with which

his works abound. His advice and exhortations of this kind are always

expressed with energy and point, often clothed in the happiest forms

of imagery; and hence it has come to pass, that such passages are

perhaps more familiar to the general reader than any other part of

his writings. Nor are Bacon's counsels without their importance, when

we have to do with those subjects in which prejudice and partiality

exercise their peculiar sway. Questions of politics and morals,

of manners, taste, or history, cannot be subjected to a scheme of

rigorous induction; and though on such matters we venture to assert

general principles, these are commonly obtained with some degree of

insecurity, and depend upon special habits of thought, not upon mere

logical connexion. Here, therefore, the intellect may be perverted,

by mixing, with the pure reason, our gregarious affections, or our

individual propensities; the false suggestions involved in language,

or the imposing delusions of received theories. In these dim and

complex labyrinths of human thought, _the Idol of the Tribe_, or _of

the Den_, _of the Forum_, or _of the Theatre_, may occupy men's minds

with delusive shapes, and may obscure or pervert their vision of truth.

But in that Natural Philosophy with which we are here concerned, there

is little opportunity for such influences. As far as a physical theory

is completed through all the steps of a just induction, there is a

clear daylight diffused over it which leaves no lurking-place for

prejudice. Each part can be examined separately and repeatedly; and

the theory is not to be deemed perfect till it will bear the scrutiny

of all sound minds alike. Although, therefore, Bacon, by warning men

against the idols of fallacious images above spoken of, may have

guarded them from dangerous error, his precepts have little to do with

Natural Philosophy: and we cannot agree with him when he says[184],

that the doctrine concerning these idols bears the same relation to

the interpretation of nature as the doctrine concerning sophistical

paralogisms bears to common logic.

(IX.) 21. _His Aim, Utility._--There is one very prominent feature in

Bacon's speculations which we must not omit to notice; it is a leading

and constant object with him to apply his knowledge to _Use_. The

insight which he obtains into nature, he would employ in commanding

nature for the service of man. He wishes to have not only principles

but works. The phrase which best describes the aim of his philosophy is

his own[185], "Ascendendo ad _axiomata_, descendendo ad _opera_." This

disposition appears in the first aphorism of the _Novum Organon_, and

runs through the work. "Man, the _minister_ and interpreter of nature,

_does_ and understands, so far as he has, in fact or in thought,

observed the course of nature; and he cannot know or _do_ more than

this." It is not necessary for us to dwell much upon this turn of mind;

for the whole of our present inquiry goes upon the supposition that an

acquaintance with the laws of nature is worth our having for its own

sake. It may be universally true, that Knowledge is Power; but we have

to do with it not as Power, but as Knowledge. It is the formation of

Science, not of Art, with which we are here concerned. It may give a

peculiar interest to the history of science, to show how it constantly

tends to provide better and better for the wants and comforts of the

body; but _that_ is not the interest which engages us in our present

inquiry into the nature and course of philosophy. The consideration

of the means which promote man's material well-being often appears to

be invested with a kind of dignity, by the discovery of general laws

which it involves; and the satisfaction which rises in our minds at

the contemplation of such cases, men sometimes ascribe, with a false

ingenuity, to the love of mere bodily enjoyment. But it is never

difficult to see that this baser and coarser element is not the real

source of our admiration. Those who hold that it is the main business

of science to construct instruments for the uses of life, appear

sometimes to be willing to accept the consequence which follows from

such a doctrine, that the first shoemaker was a philosopher worthy of

the highest admiration[186]. But those who maintain such paradoxes,

often, by a happy inconsistency, make it their own aim, not to devise

some improved covering for the feet, but to delight the mind with acute

speculations, exhibited in all the graces of wit and fancy.

It has been said[187] that the key of the Baconian doctrine consists in

two words, Utility and Progress. With regard to the latter point, we

have already seen that the hope and prospect of a boundless progress in

human knowledge had sprung up in men's minds, even in the early times

of imperial Rome; and were most emphatically expressed by that very

Seneca who disdained to reckon the worth of knowledge by its value in

food and clothing. And when we say that Utility was the great business

of Bacon's philosophy, we forget one-half of his characteristic phrase:

"Ascendendo ad aximomata," no less than "descendendo ad opera," was,

he repeatedly declared, the scheme of his path. He constantly spoke,

we are told by his secretary[188], of two kinds of experiments,

_experimenta fructifera_, and _experimenta lucifera_.

Again; when we are told by modern writers that Bacon merely recommended

such induction as all men instinctively practise, we ought to recollect

his own earnest and incessant declarations to the contrary. The

induction hitherto practised is, he says, of no use for obtaining solid

science. There are two ways[189], "hæc via in usu est," "altera vera,

sed intentata." Men have constantly been employed in _anticipation_;

in illicit induction. The intellect left to itself rushes on in this

road[190]; the conclusions so obtained are persuasive[191]; far more

persuasive than inductions made with due caution[192]. But still this

method must be rejected if we would obtain true knowledge. We shall

then at length have ground of good hope for science when we proceed

in another manner[193]. We must rise, not by a leap, but by small

steps, by successive advances, by a gradation of ascents, trying our

facts, and clearing our notions at every interval. The scheme of true

philosophy, according to Bacon, is not obvious and simple, but long and

technical, requiring constant care and self-denial to follow it. And we

have seen that, in this opinion, his judgment is confirmed by the past

history and present condition of science.

Again; it is by no means a just view of Bacon's character to place

him in contrast to Plato. Plato's philosophy was the philosophy of

Ideas; but it was not left for Bacon to set up the philosophy of

Facts in opposition to that of Ideas. That had been done fully by the

speculative reformers of the sixteenth century. Bacon had the merit of

showing that Facts and Ideas must be combined; and not only so, but of

divining many of the special rules and forms of this combination, when

as yet there were no examples of them, with a sagacity hitherto quite

unparalleled.

(X.) 22. _His Perseverance._--With Bacon's unhappy political life we

have here nothing to do. But we cannot but notice with pleasure how

faithfully, how perseveringly, how energetically he discharged his

great philosophical office of a Reformer of Methods. He had conceived

the purpose of making this his object at an early period. When

meditating the continuation of his _Novum Organon_, and speaking of

his reasons for trusting that his work will reach some completeness

of effect, he says[194], "I am by two arguments thus persuaded.

First, I think thus from the zeal and constancy of my mind, which has

not waxed old in this design, nor, after so many years, grown cold

and indifferent; I remember that about forty years ago I composed

a juvenile work about these things, which with great contrivance

and a pompous title I called _temporis partum maximum_, or the most

considerable birth of time; Next, that on account of its usefulness,

it may hope the Divine blessing." In stating the grounds of hope for

future progress in the sciences, he says[195]: "Some hope may, we

conceive, be ministered to men by our own example: and this we say, not

for the sake of boasting, but because it is useful to be said. If any

despond, let them look at me, a man among all others of my age most

occupied with civil affairs, nor of very sound health, (which brings a

great loss of time;) also in this attempt the first explorer, following

the footsteps of no man, nor communicating on these subjects with any

mortal; yet, having steadily entered upon the true road and made my

mind submit to things themselves, one who has, in this undertaking,

made, (as we think,) some progress." He then proceeds to speak of what

may be done by the combined and more prosperous labours of others,

in that strain of noble hope and confidence, which rises again and

again, like a chorus, at intervals in every part of his writings. In

the _Advancement of Learning_ he had said, "I could not be true and

constant to the argument I handle, if I were not willing to go beyond

others, but yet not more willing than to have others go beyond me

again." In the Preface to the _Instauratio Magna_, he had placed among

his postulates those expressions which have more than once warmed the

breast of a philosophical reformer[196]. "Concerning ourselves we

speak not; but as touching the matter which we have in hand, this we

ask;--that men be of good hope, neither feign and imagine to themselves

this our Reform as something of infinite dimension and beyond the grasp

of mortal man, when in truth it is the end and true limit of infinite

error; and is by no means unmindful of the condition of mortality and

humanity, not confiding that such a thing can be carried to its perfect

close in the space of a single age, but assigning it as a task to a

succession of generations." In a later portion of the _Instauratio_ he

says: "We bear the strongest love to the _human republic_ our common

country; and we by no means abandon the hope that there will arise and

come forth some man among posterity, who will be able to receive and

digest all that is best in what we deliver; and whose care it will be

to cultivate and perfect such things. Therefore, by the blessing of the

Deity, to tend to this object, to open up the fountains, to discover

the useful, to gather guidance for the way, shall be our task; and from

this we shall never, while we remain in life, desist."

(XI.) 23. _His Piety._--We may add, that the spirit of piety as well as

of hope which is seen in this passage, appears to have been habitual

to Bacon at all periods of his life. We find in his works several

drafts of portions of his great scheme, and several of them begin with

a prayer. One of these entitled, in the edition of his works, "The

Student's Prayer," appears to me to belong probably to his early youth.

Another, entitled "The Writer's Prayer," is inserted at the end of

the Preface of the _Instauratio_, as it was finally published. I will

conclude my notice of this wonderful man by inserting here these two

prayers.

"To God the Father, God the Word, God the Spirit, we pour forth most

humble and hearty supplications; that he, remembering the calamities

of mankind, and the pilgrimage of this our life, in which we wear out

days few and evil, would please to open to us new refreshments out of

the fountains of his goodness for the alleviating of our miseries.

This also we humbly and earnestly beg, that human things may not

prejudice such as are divine; neither that, from the unlocking of the

gates of sense, and the kindling of a greater natural light, anything

of incredulity, or intellectual night, may arise in our minds towards

divine mysteries. But rather, that by our mind thoroughly cleansed and

purged from fancy and vanities, and yet subject and perfectly given up

to the Divine oracles, there may be given unto faith the things that

are faith's."

"Thou, O Father, who gavest the visible light as the first-born of

thy creatures, and didst pour into man the intellectual light as the

top and consummation of thy workmanship, be pleased to protect and

govern this work, which coming from thy goodness, returneth to thy

glory. Thou, after thou hadst reviewed the works which thy hands had

made, beheldest that everything was very good, and thou didst rest

with complacency in them. But man, reflecting on the works which he

had made, saw that all was vanity and vexation of spirit, and could by

no means acquiesce in them. Wherefore, if we labour in thy works with

the sweat of our brows, thou wilt make us partakers of thy vision and

thy Sabbath. We humbly beg that this mind may be steadfastly in us;

and that thou, by our hands, and also by the hands of others on whom

thou shalt bestow the same spirit, wilt please to convey a largess

of new alms to thy family of mankind. These things we commend to thy

everlasting love, by our Jesus, thy Christ, God with us. Amen."

FOOTNOTES:

[Footnote 168: And in other passages: thus, "Ego enim buccinator tantum

pugnam non ineo." _Nov. Org._ lib. iv. c. i.]

[Footnote 169: Lib. 1. Aphor. 78 _et seq._]

[Footnote 170: _Aug. Sc._ Lib. iii. c. 4. p. 194. So in other places,

as _Nov. Org._ i. Aph. 104. "De scientiis tum demum bene sperandum est

quando per scalam veram et per gradus continuos, et non intermissos aut

hiulcos a particularibus ascendetur ad axiomata minora, et deinde ad

media, alia aliis superiora, et postremo demum ad generalissima."]

[Footnote 171: _Nov. Org._ 1. Aph. 22.]

[Footnote 172: _Ib._ Aph. 20.]

[Footnote 173: 1 Ax. 15.]

[Footnote 174: _Nov. Org._ lib. ii. Aph. 19.]

[Footnote 175: _Inst. Mag._ par. iii. (vol. viii. p. 244).]

[Footnote 176: _Hist. Ind. Sc._ b. x. c. i.]

[Footnote 177: _Ib._ c. iv.]

[Footnote 178: _Nov. Org._ lib. i. Aph. 61.]

[Footnote 179: _Nov. Org._ lib. ii. Aph. 10.]

[Footnote 180: Aph. 11.]

[Footnote 181: Aph. 15, p. 105.]

[Footnote 182: Page 110.]

[Footnote 183: Herschel, _On the Study of Nat. Phil._ Art. 192.]

[Footnote 184: _Nov. Org._ lib. i. Aph. 40.]

[Footnote 185: _Nov. Org._ lib. i. Ax. 103.]

[Footnote 186: _Edinb. Rev._ No. cxxxii. p. 65.]

[Footnote 187: _Ib._]

[Footnote 188: Pref. to the _Nat. Hist._ i. 243.]

[Footnote 189: _Nov. Org._ lib. i. Aph. 19.]

[Footnote 190: _Ibid._ lib. i. Aph. 20.]

[Footnote 191: Aph. 27.]

[Footnote 192: _Ib._ 28.]

[Footnote 193: Aph. 104. So Aph. 105. "In constituendo axiomate forma

_inductionis_ alia quam adhuc in usu fuit excogitanda est," &c.]

[Footnote 194: _Ep. ad P. Fulgentium._ _Op._ x. 330.]

[Footnote 195: _Nov. Org._ i. Aph. 113.]

[Footnote 196: See the motto to Kant's _Kritik der Reinen Vernunft_.]

CHAPTER XVI.

ADDITIONAL REMARKS ON FRANCIS BACON.

Francis Bacon and his works have recently been discussed and examined

by various writers in France and Germany as well as England[197]. Not

to mention smaller essays, M. Bouillet has published a valuable edition

of his philosophical works; Count Joseph de Maistre wrote a severe

critique of his philosophy, which has been published since the death of

the author; M. Charles Remusat has written a lucid and discriminating

Essay on the subject; and in England we have had a new edition of the

works published, with a careful and thoughtful examination of the

philosophy which they contain, written by one of the editors: a person

especially fitted for such an examination by an acute intellect, great

acquaintance with philosophical literature, and a wide knowledge of

modern science. Robert Leslie Ellis, the editor of whom I speak, died

during the publication of the edition, and before he had done full

justice to his powers; but he had already written various dissertations

on Bacon's philosophy, which accompany the different Treatises in the

new edition.

Mr. Ellis has given a more precise view than any of his predecessors

had done of the nature of Bacon's induction and of his philosophy of

discovery. Bacon's object was to discover the 'natures' or essences

of things, in order that he might reproduce these natures or essences

at will; he conceived that these natures were limited in number, and

manifested in various combinations in the bodies which exist in the

universe; so that by accumulating observations of them in a multitude

of cases, we may learn by induction in what they do and in what

they do not consist; the _Induction_ which is to be used for this

purpose consists in a great measure of _excluding_ the cases which

do not exhibit the 'nature' in question; and by such exclusion, duly

repeated, we have at last left in our hands the elements of which the

proposed nature consists. And the knowledge which is thus obtained may

be applied to reproduce the things so analysed. As exhibiting this

view clearly we may take a passage in the _Sylva Sylvarum_: "Gold has

these natures: greatness of weight, closeness of parts, fixation,

pliantness or softness, immunity from rust, colour or tincture of

yellow. Therefore the sure way, though most about, to make gold, is to

know the causes of the several natures before rehearsed, and the axioms

concerning the same. For if a man can make a metal, that hath all these

properties, let men dispute whether it be gold or no." He means that

however they dispute, it is gold for all practical purposes.

For such an Induction as this, Bacon claims the merit both of

being certain, and of being nearly independent of the ingenuity of

the inquirer. It is a method which enables all men to make exact

discoveries, as a pair of compasses enables all men to draw an exact

circle.

Now it is necessary for us, who are exploring the progress of the true

philosophy of discovery, to say plainly that this part of Bacon's

speculation is erroneous and valueless. No scientific discovery ever

has been made in this way. Men have not obtained truths concerning

the natural world by seeking for the natures of things, and by

extracting them from phenomena by rejecting the cases in which they

were not. On the contrary, they have begun by ascertaining the _laws

of the phenomena_; and have then gone on, not by a mechanical method

which levels all intellect, but by special efforts of the brightest

intellects to catch hold of the ideas by which these laws of phenomena

might be interpreted and expressed in more general terms. These two

steps, the finding the laws of phenomena, and finding the conceptions

by which those laws can be expressed, are really the course of

discovery, as the history of science exhibits it to us.

Bacon, therefore, according to the view now presented, was wrong both

as to his object and as to his method. He was wrong in taking for his

object the essences of things,--the causes of abstract properties:

for these man cannot, or can very rarely discover; and all Bacon's

ingenuity in enumerating and classifying these essences and abstract

properties has led, and could lead, to no result. The vast results

of modern science have been obtained, not by seeking and finding the

essences of things, but by exploring the laws of phenomena and the

causes of those laws.

And Bacon's method, as well as his object, is vitiated by a pervading

error:--the error of supposing that to be done by method which must

be done by mind;--that to be done by rule which must be done by a

flight beyond rule;--that to be mainly negative which is eminently

positive;--that to depend on other men which must depend on the

discoverer himself;--that to be mere prose which must have a dash of

poetry;--that to be a work of mere labour which must be also a work of

genius.

Mr. Ellis has seen very clearly and explained very candidly that this

method thus recommended by Bacon has not led to discovery. "It is," he

says, "neither to the technical part of his method nor to the details

of his view of the nature and progress of science, that his great fame

is justly owing. His merits are of another kind. They belong to the

spirit rather than to the positive precepts of his philosophy."

As the reader of the last chapter will see, this amounts to much the

same as the account which I had given of the positive results of

Bacon's method, and the real value of that portion of his philosophy

which he himself valued most. But still there remain, as I have also

noted, portions of Bacon's speculations which have a great and enduring

value, namely, his doctrine that Science is the Interpretation of

Nature, his distinction of this Interpretation of Nature from the

vicious and premature Anticipation of Nature which had generally

prevailed till then; and the recommendation of a graduated and

successive induction by which alone the highest and most general

truths were to be reached. These are points which he urges with great

clearness and with great earnestness; and these are important points in

the true philosophy of discovery.

I may add that Mr. Ellis agrees with me in noting the invention of

the conception by which the laws of phenomena are interpreted as

something additional to _Induction_, both in the common and in the

Baconian sense of the word. He says (General Preface, Art. 9), "In

all cases this process [scientific discovery] involves an element to

which nothing corresponds in the Tables of Comparence and Exclusion;

namely the application to the facts of a _principle_ of arrangement,

an _idea_, existing in the mind of the discoverer antecedently to the

act of induction." It may be said that this principle or idea is aimed

at in the Baconian analysis. "And this is in one sense true: but it

must be added, that this _analysis_, if it be thought right to call it

so, is of the essence of the discovery which results from it. To take

for granted that it has been already effected is simply a _petitio

principii_. In most cases the mere act of induction follows as a matter

of course as soon as the _appropriate idea_ has been introduced." And

as an example he takes Kepler's invention of the ellipse, as the idea

by which Mars's motions could be reduced to law; making the same use of

this example which we have repeatedly made of it.

Mr. Ellis may at first sight appear to express himself more favourably

than I have done, with regard to the value of Bacon's _Inquisitio in

Naturam Calidi_ in the Second Book of the _Novum Organon_. He says of

one part of it[198]: "Bacon here anticipates not merely the essential

character of the most recent theory of heat, but also the kind of

evidence by which it has been established.... The merit of having

perceived the true significance of the production of heat by friction

belongs of right to Bacon."

But notwithstanding this, Mr. Ellis's general judgment on this specimen

of Bacon's application of his own method does not differ essentially

from mine. He examines the _Inquisitio_ at some length, and finally

says: "If it were affirmed that Bacon, after having had a glimpse of

the truth suggested by some obvious phenomena, had then recourse, as he

himself expresses it, to certain 'differentiæ inanes' in order to save

the phenomena, I think it would be hard to dispute the truth of the

censure."

Another of the Editors of this edition (Mr. Spedding) fixes his

attention upon another of the features of the method of discovery

proposed by Bacon, and is disposed to think that the proposed method

has never yet had justice done it, because it has not been tried in the

way and on the scale that Bacon proposes[199]. Bacon recommended that

a great collection of facts should be at once made and accumulated,

regarding every branch of human knowledge; and conceived that, when

this had been done by common observers, philosophers might extract

scientific truths from this mass of facts by the application of a right

method. This separation of the offices of the observer and discoverer,

Mr. Spedding thinks is shown to be possible by such practical examples

as meteorological observations, made by ordinary observers, and

reduced to tables and laws by a central calculator; by hydrographical

observations made by ships provided with proper instructions, and

reduced to general laws by the man of science in his study; by

magnetical observations made by many persons in every part of the

world, and reduced into subservience to theory by mathematicians at

home.

And to this our reply will be, in the terms which the history of

all the Sciences has taught us, that such methods of procedure as

this do not belong to the _Epoch of Discovery_, but to the Period of

_verification_ and _application_ of the discovery which follows. When a

theory has been established in its general form, our knowledge of the

distribution of its phenomena in time and space can be much promoted

by ordinary observers scattered over the earth, and succeeding each

other in time, provided they are furnished with instruments and methods

of observation, duly constructed on the principles of science; but

such observers cannot in any degree supersede the discoverer who is

first to establish the theory, and to introduce into the facts a new

principle of order. When the laws of nature have been caught sight

of, much may be done, even by ordinary observers, in verifying and

exactly determining them; but when a real discovery is to be made,

this separation of the observer and the theorist is not possible. In

those cases, the questioning temper, the busy suggestive mind, is

needed at every step, to direct the operating hand or the open gaze.

No possible accumulation of facts about mixture and heat, collected in

the way of blind trial, could have led to the doctrines of chemistry,

or crystallography, or the atomic theory, or voltaic and chemical

and magnetic polarity, or physiology, or any other science. Indeed

not only is an existing theory requisite to supply the observer with

instruments and methods, but without theory he cannot even describe his

observations. He says that he mixes an acid and an alkali; but what

is an acid? What is an alkali? How does he know them? He classifies

crystals according to their forms: but till he has learnt what is

distinctive in the form of a crystal, he cannot distinguish a cube

from a square prism, even if he had a goniometer and could use it. And

the like impossibility hangs over all the other subjects. To report

facts for scientific purposes without some aid from theory, is not only

useless, but impossible.

When Mr. Spedding says, "I could wish that men of science would apply

themselves earnestly to the solution of this practical problem:

What measures are to be taken in order that the greatest variety of

judicious observations of nature all over the world may be carried on

in concert upon a common plan and brought to a common centre:"--he is

urging upon men of science to do what they have always done, so far

as they have had any power, and in proportion as the state of science

rendered such a procedure possible and profitable to science. In

Astronomy, it has been done from the times of the Greeks and even of

the Chaldeans, having been begun _as soon as_ the heavens were reduced

to law at all. In meteorology, it has been done extensively, though to

little purpose, because the weather has _not yet_ been reduced to rule.

Men of science have shown how barometers, thermometers, hygrometers,

and the like, may be constructed; and these may be now read by any one

as easily as a clock; but of ten thousand meteorological registers

thus kept by ordinary observers, what good has come to science?

Again: The laws of the tides have been in a great measure determined

by observations in all parts of the globe, _because_ theory pointed

out what was to be observed. In like manner the facts of terrestrial

magnetism were ascertained with tolerable completeness by extended

observations, _then_, and then only, when a most recondite and profound

branch of mathematics had pointed out what was to be observed, and most

ingenious instruments had been devised by men of science for observing.

And even with these, it requires an education to use the instruments.

But in many cases no education in the use of instruments devised by

others can supersede the necessity of a theoretical and suggestive

spirit in the inquirer himself. He must devise his own instruments

and his own methods, if he is to make any discovery. What chemist, or

inquirer about polarities, or about optical laws yet undiscovered, can

make any progress by using another man's experiments and observations?

He must invent at every step of his observation; and the observer and

theorist can no more be dissevered, than the body and soul of the

inquirer.

That persons of moderate philosophical powers may, when duly

educated, make observations which may be used by greater discoverers

than themselves, is true. We have examples of such a subordination

of scientific offices in astronomy, in geology, and in many other

departments. But still, as I have said, a very considerable degree of

scientific education is needed even for the subordinate labourers in

science; and the more considerable in proportion as science advances

further and further; since every advance implies a knowledge of what

has already been done, and requires a new precision or generality in

the new points of inquiry.

FOOTNOTES:

[Footnote 197: _Œuvres Philosophiques de Bacon, &c._ par M. N.

Bouillet, 3 Tomes.

_Examen de la Philosophie de Bacon_ (_Œuvres Posthumes_ du Comte J. de

Maistre).

_Bacon, sa Vie, son Temps, sa Philosophie_, par Charles de Remusat.

_Histoire de la Vie et des Ouvrages de François Bacon_, par J. B. de

Vaugelles.

_Franz Baco von Verulam_, von Kuno Fischer.

_The Works of Francis Bacon_, collected and edited by James Spedding,

Robert Leslie Ellis, and Douglas Denon Heath.]

[Footnote 198: Note to Aph. xviii.]

[Footnote 199: Pref. to the _Parasceue_, Vol. i. p. 382.]

CHAPTER XVII.

FROM BACON TO NEWTON.

1. _Harvey._--We have already seen that Bacon was by no means the

first mover or principal author of the revolution in the method of

philosophizing which took place in his time; but only the writer who

proclaimed in the most impressive and comprehensive manner, the scheme,

the profit, the dignity, and the prospects of the new philosophy.

Those, therefore, who after him, took up the same views are not to be

considered as his successors, but as his fellow-labourers; and the

line of historical succession of opinions must be pursued without

special reference to any one leading character, as the principal figure

of the epoch. I resume this line, by noticing a contemporary and

fellow-countryman of Bacon, Harvey, the discoverer of the circulation

of the blood. This discovery was not published and generally accepted

till near the end of Bacon's life; but the anatomist's reflections

on the method of pursuing science, though strongly marked with the

character of the revolution that was taking place, belong to a very

different school from the Chancellor's. Harvey was a pupil of Fabricius

of Acquapendente, whom we noticed among the practical reformers of the

sixteenth century. He entertained, like his master, a strong reverence

for the great names which had ruled in philosophy up to that time,

Aristotle and Galen; and was disposed rather to recommend his own

method by exhibiting it as the true interpretation of ancient wisdom,

than to boast of its novelty. It is true, that he assigns, as his

reason for publishing some of his researches[200], "that by revealing

the method I use in searching into things, I might propose to studious

men, a new and (if I mistake not) a surer path to the attainment of

knowledge[201];" but he soon proceeds to fortify himself with the

authority of Aristotle. In doing this, however, he has the very great

merit of giving a living and practical character to truths which exist

in the Aristotelian works, but which had hitherto been barren and empty

professions. We have seen that Aristotle had asserted the importance

of experience as one root of knowledge; and in this had been followed

by the schoolmen of the middle ages: but this assertion came with very

different force and effect from a man, the whole of whose life had been

spent in obtaining, by means of experience, knowledge which no man had

possessed before. In Harvey's general reflections, the necessity of

both the elements of knowledge, sensations and ideas, experience and

reason, is fully brought into view, and rightly connected with the

metaphysics of Aristotle. He puts the antithesis of these two elements

with great clearness. "Universals are chiefly known to us, for science

is begot by reasoning from universals to particulars; yet that very

comprehension of universals in the understanding springs from the

perception of singulars in our sense." Again, he quotes Aristotle's

apparently opposite assertions:--that made in his _Physics_[202],

"that we must advance from things which are first known to us, though

confusedly, to things more distinctly intelligible in themselves;

from the whole to the part; from the universal to the particular;"

and that made in the _Analytics_[203]; that "Singulars are more known

to us and do first exist according to sense: for nothing is in the

understanding which was not before in the sense." Both, he says, are

true, though at first they seem to clash: for "though in knowledge

we begin with sense, sensation itself is a universal thing." This he

further illustrates; and quotes Seneca, who says, that "Art itself is

nothing but the _reason_ of the work, implanted in the Artist's mind:"

and adds, "the same way by which we gain an Art, by the very same way

we attain any kind of science or knowledge whatever; for as Art is

a habit whose object is something to be done, so Science is a habit

whose object is something to be known; and as the former proceedeth

from the imitation of examples, so this latter, from the knowledge of

things natural. The source of both is from sense and experience; since

[but?] it is impossible that Art should be rightly purchased by the one

or Science by the other without a direction from ideas." Without here

dwelling on the relation of Art and Science, (very justly stated by

Harvey, except that ideas exist in a very different form in the mind

of the Artist and the Scientist) it will be seen that this doctrine,

of science springing from experience with a direction from ideas, is

exactly that which we have repeatedly urged, as the true view of the

subject. From this view, Harvey proceeds to infer the importance of a

reference to sense in his own subject, not only for first discovering,

but for receiving knowledge: "Without experience, not other men's but

our own, no man is a proper disciple of any part of natural knowledge;

without experimental skill in anatomy, he will no better apprehend

what I shall deliver concerning generation, than a man born blind can

judge of the nature and difference of colours, or one born deaf, of

sounds." "If we do otherwise, we may get a humid and floating opinion,

but never a solid and infallible knowledge: as is happenable to those

who see foreign countries only in maps, and the bowels of men falsely

described in anatomical tables. And hence it comes about, that in this

rank age, we have many sophisters and bookwrights, but few wise men

and philosophers." He had before declared "how unsafe and degenerate a

thing it is, to be tutored by other men's commentaries, without making

trial of the things themselves; especially since Nature's book is so

open and legible." We are here reminded of Galileo's condemnation

of the "paper philosophers." The train of thought thus expressed by

the practical discoverers, spread rapidly with the spread of the

new knowledge that had suggested it, and soon became general and

unquestioned.

2. _Descartes._--Such opinions are now among the most familiar and

popular of those which are current among writers and speakers; but

we should err much if we were to imagine that after they were once

propounded they were never resisted or contradicted. Indeed, even in

our own time, not only are such maxims very often practically neglected

or forgotten, but the opposite opinions, and views of science quite

inconsistent with those we have been explaining, are often promulgated

and widely accepted. The philosophy of pure ideas has its commonplaces,

as well as the philosophy of experience. And at the time of which

we speak, the former philosophy, no less than the latter, had its

great asserter and expounder; a man in his own time more admired than

Bacon, regarded with more deference by a large body of disciples all

over Europe, and more powerful in stirring up men's minds to a new

activity of inquiry. I speak of Descartes, whose labours, considered

as a philosophical system, were an endeavour to revive the method

of obtaining knowledge by reasoning from our own ideas only, and to

erect it in opposition to the method of observation and experiment.

The Cartesian philosophy contained an attempt at a counter-revolution.

Thus in this author's _Principia Philosophiæ_[204], he says that "he

will give a short account of the principal phenomena of the world,

not that he may use them as reasons to prove anything; for," adds he,

"we desire to deduce effects from causes, not causes from effects;

but only in order that out of the innumerable effects which we learn

to be capable of resulting from the same causes, we may determine our

mind to consider some rather than others." He had before said, "The

principles which we have obtained [by pure _à priori_ reasoning] are so

vast and so fruitful, that many more consequences follow from them than

we see contained in this visible world, and even many more than our

mind can ever take a full survey of." And he professes to apply this

method in detail. Thus in attempting to state the three fundamental

laws of motion, he employs only _à priori_ reasonings, and is in fact

led into error in the third law which he thus obtains[205]. And in

his _Dioptrics_[206] he pretends to deduce the laws of reflection

and refraction of light from certain comparisons (which are, in

truth, arbitrary,) in which the radiation of light is represented

by the motion of a ball impinging upon the reflecting or refracting

body. It might be represented as a curious instance of the caprice

of fortune, which appears in scientific as in other history, that

Kepler, professing to derive all his knowledge from experience, and

exerting himself with the greatest energy and perseverance, failed in

detecting the law of refraction; while Descartes, who professed to be

able to despise experiment, obtained the true law of sines. But as we

have stated in the _History_[207], Descartes appears to have learnt

this law from Snell's papers. And whether this be so or not, it is

certain that notwithstanding the profession of independence which his

philosophy made, it was in reality constantly guided and instructed by

experience. Thus in explaining the Rainbow (in which his portion of

the discovery merits great praise) he speaks[208] of taking a globe

of glass, allowing the sun to shine on one side of it, and noting the

colours produced by rays after two refractions and one reflection.

And in many other instances, indeed in all that relates to physics,

the reasonings and explanations of Descartes and his followers were,

consciously or unconsciously, directed by the known facts, which they

had observed themselves or learnt from others.

But since Descartes thus, speculatively at least, set himself in

opposition to the great reform of scientific method which was going

on in his time, how, it may be asked, did he acquire so strong an

influence over the most active minds of his time? How is it that he

became the founder of a large and distinguished school of philosophers?

How is it that he not only was mainly instrumental in deposing

Aristotle from his intellectual throne, but for a time appeared to have

established himself with almost equal powers, and to have rendered the

Cartesian school as firm a body as the Peripatetic had been?

The causes to be assigned for this remarkable result are, I conceive,

the following. In the first place, the physicists of the Cartesian

school did, as I have just stated, found their philosophy upon

experiment, and did not practically, or indeed, most of them,

theoretically, assent to their master's boast of showing what the

phenomena _must be_, instead of looking to see what they _are_. And

as Descartes had really incorporated in his philosophy all the chief

physical discoveries of his own and preceding times, and had delivered,

in a more general and systematic shape than any one before him, the

principles which he thus established, the physical philosophy of his

school was in reality far the best then current; and was an immense

improvement upon the Aristotelian doctrines, which had not yet been

displaced as a system. Another circumstance which gained him much

favour, was the bold and ostentatious manner in which he professed

to begin his philosophy by liberating himself from all preconceived

prejudice. The first sentence of his philosophy contains this

celebrated declaration: "Since," he says, "we begin life as infants,

and have contracted various judgments concerning sensible things before

we possess the entire use of our reason, we are turned aside from the

knowledge of truth by many prejudices: from which it does not appear

that we can be any otherwise delivered, than if once in our life we

make it our business to doubt of everything in which we discern the

smallest suspicion of uncertainty." In the face of this sweeping

rejection or unhesitating scrutiny of all preconceived opinions,

the power of the ancient authorities and masters in philosophy must

obviously shrink away; and thus Descartes came to be considered as

the great hero of the overthrow of the Aristotelian dogmatism. But

in addition to these causes, and perhaps more powerful than all in

procuring the assent of men to his doctrines, came the deductive and

systematic character of his philosophy. For although all knowledge of

the external world is in reality only to be obtained from observation,

by inductive steps,--minute, perhaps, and slow, and many, as Galileo

and Bacon had already taught;--the human mind conforms to these

conditions reluctantly and unsteadily, and is ever ready to rush to

general principles, and then to employ itself in deducing conclusions

from these by synthetical reasonings; a task grateful, from the

distinctness and certainty of the result, and the accompanying feeling

of our own sufficiency. Hence men readily overlooked the precarious

character of Descartes' fundamental assumptions, in their admiration

of the skill with which a varied and complex Universe was evolved out

of them. And the complete and systematic character of this philosophy

attracted men no less than its logical connexion. I may quote here

what a philosopher[209] of our own time has said of another writer:

"He owed his influence to various causes; at the head of which may be

placed that genius for system which, though it cramps the growth of

knowledge, perhaps finally atones for that mischief by the zeal and

activity which it rouses among followers and opponents, who discover

truth by accident when in pursuit of weapons for their warfare. A

system which attempts a task so hard as that of subjecting vast

provinces of human knowledge to one or two principles, if it presents

some striking instances of conformity to superficial appearances, is

sure to delight the framer; and for a time to subdue and captivate the

student too entirely for sober reflection and rigorous examination. In

the first instance consistency passes for truth. When principles in

some instances have proved sufficient to give an unexpected explanation

of facts, the delighted reader is content to accept as true all other

deductions from the principles. Specious premises being assumed to be

true, nothing more can be required than logical inference. Mathematical

forms pass current as the equivalent of mathematical certainty. The

unwary admirer is satisfied with the completeness and symmetry of the

plan of his house, unmindful of the need of examining the firmness of

the foundation and the soundness of the materials. The system-maker,

like the conqueror, long dazzles and overawes the world; but when their

sway is past, the vulgar herd, unable to measure their astonishing

faculties, take revenge by trampling on fallen greatness." Bacon

showed his wisdom in his reflections on this subject, when he said

that "Method, carrying a show of total and perfect knowledge, hath a

tendency to generate acquiescence."

The main value of Descartes' physical doctrines consisted in their

being arrived at in a way inconsistent with his own professed method,

namely, by a reference to observation. But though he did in reality

begin from facts, his system was nevertheless a glaring example

of that error which Bacon had called _Anticipation_; that illicit

generalization which leaps at once from special facts to principles

of the widest and remotest kind; such, for instance, as the Cartesian

doctrine, that the world is an absolute _plenum_, every part being

full of matter of some kind, and that all natural effects depend on

the laws of motion. Against this fault, to which the human mind is

so prone, Bacon had lifted his warning voice in vain, so far as the

Cartesians were concerned; as indeed, to this day, one theorist after

another pursues his course, and turns a deaf ear to the Verulamian

injunctions; perhaps even complacently boasts that he founds his theory

upon observation; and forgets that there are, as the aphorism of the

_Novum Organon_ declares, two ways by which this may be done;--the one

hitherto in use and suggested by our common tendencies, but barren and

worthless; the other almost untried, to be pursued only with effort and

self-denial, but alone capable of producing true knowledge.

3. _Gassendi._--Thus the lessons which Bacon taught were far from being

generally accepted and applied at first. The amount of the influence of

these two men, Bacon and Descartes, upon their age, has often been a

subject of discussion. The fortunes of the Cartesian school have been

in some measure traced in the History of Science. But I may mention the

notice taken of these two philosophers by Gassendi, a contemporary and

countryman of Descartes. Gassendi, as I have elsewhere stated[210],

was associated with Descartes in public opinion, as an opponent of the

Aristotelian dogmatism; but was not in fact a follower or profound

admirer of that writer. In a Treatise on Logic, Gassendi gives an

account of the Logic of various sects and authors; treating, in order,

of the Logic of Zeno (the Eleatic), of Euclid (the Megarean), of

Plato, of Aristotle, of the Stoics, of Epicurus, of Lullius, of Ramus;

and to these he adds the Logic of Verulam, and the Logic of Cartesius.

"We must not," he says, "on account of the celebrity it has obtained,

pass over the Organon or Logic of Francis Bacon Lord Verulam, High

Chancellor of England, whose noble purpose in our time it has been, to

make an Instauration of the Sciences." He then gives a brief account

of the _Novum Organon_, noticing the principal features in its rules,

and especially the distinction between the vulgar induction which leaps

at once from particular experiments to the more general axioms, and

the chastised and gradual induction, which the author of the _Organon_

recommends. In his account of the Cartesian Logic, he justly observes,

that "He too imitated Verulam in this, that being about to build up a

new philosophy from the foundation, he wished in the first place to lay

aside all prejudice: and having then found some solid principle, to

make that the groundwork of his whole structure. But he proceeds by a

very different path from that which Verulam follows; for while Verulam

seeks aid from things, to perfect the cogitation of the intellect,

Cartesius conceives, that when we have laid aside all knowledge of

things, there is, in our thoughts alone, such a resource, that the

intellect may by its own power arrive at a perfect knowledge of all,

even the most abstruse things."

The writings of Descartes have been most admired, and his method

most commended, by those authors who have employed themselves upon

metaphysical rather than physical subjects of inquiry. Perhaps we might

say that, in reference to such subjects, this method is not so vicious

as at first, when contrasted with the Baconian induction, it seems to

be: for it might be urged that the _thoughts_ from which Descartes

begins his reasonings are, in reality, _experiments_ of the kind which

the subject requires us to consider: each such thought is a fact in

the intellectual world; and of such facts, the metaphysician seeks to

discover the laws. I shall not here examine the validity of this plea;

but shall turn to the consideration of the actual progress of physical

science, and its effect on men's minds.

4. _Actual progress in Science._--The practical discoverers were indeed

very active and very successful during the seventeenth century, which

opened with Bacon's survey and exhortations. The laws of nature, of

which men had begun to obtain a glimpse in the preceding century, were

investigated with zeal and sagacity, and the consequence was that the

foundations of most of the modern physical sciences were laid. That

mode of research by experiment and observation, which had, a little

time ago, been a strange, and to many, an unwelcome innovation, was now

become the habitual course of philosophers. The revolution from the

philosophy of tradition to the philosophy of experience was completed.

The great discoveries of Kepler belonged to the preceding century.

They are not, I believe, noticed, either by Bacon or by Descartes; but

they gave a strong impulse to astronomical and mechanical speculators,

by showing the necessity of a sound science of motion. Such a science

Galileo had already begun to construct. At the time of which I speak,

his disciples[211] were still labouring at this task, and at other

problems which rapidly suggested themselves. They had already convinced

themselves that air had weight; in 1643 Torricelli proved this

practically by the invention of the Barometer; in 1647 Pascal proved

it still further by sending the Barometer to the top of a mountain.

Pascal and Boyle brought into clear view the fundamental laws of fluid

equilibrium; Boyle and Mariotte determined the law of the compression

of air as regulated by its elasticity. Otto Guericke invented the

air-pump, and by his "Madgeburg Experiments" on a vacuum, illustrated

still further the effects of the air. Guericke pursued what Gilbert

had begun, the observation of electrical phenomena; and these two

physicists made an important step, by detecting repulsion as well as

attraction in these phenomena. Gilbert had already laid the foundations

of the science of Magnetism. The law of refraction, at which Kepler

had laboured in vain, was, as we have seen, discovered by Snell (about

1621), and published by Descartes. Mersenne had discovered some of

the more important parts of the theory of Harmonics. In sciences of

a different kind, the same movement was visible. Chemical doctrines

tended to assume a proper degree of generality, when Sylvius in 1679

taught the opposition of acid and alkali, and Stahl, soon after,

the phlogistic theory of combustion. Steno had remarked the most

important law of crystallography in 1669, that the angles of the same

kind of crystals are always equal. In the sciences of classification,

about 1680, Ray and Morison in England resumed the attempt to form a

systematic botany, which had been interrupted for a hundred years, from

the time of the memorable essay of Cæsalpinus. The grand discovery of

the circulation of the blood by Harvey about 1619, was followed in 1651

by Pecquet's discovery of the course of the chyle. There could now no

longer be any question whether science was progressive, or whether

observation could lead to new truths.

Among these cultivators of science, such sentiments as have been

already quoted became very familiar;--that knowledge is to be sought

from nature herself by observation and experiment;--that in such

matters tradition is of no force when opposed to experience, and that

mere reasonings without facts cannot lead to solid knowledge. But I

do not know that we find in these writers any more special rules of

induction and scientific research which have since been confirmed

and universally adopted. Perhaps too, as was natural in so great a

revolution, the writers of this time, especially the second-rate

ones, were somewhat too prone to disparage the labours and talents

of Aristotle and the ancients in general, and to overlook the ideal

element of our knowledge, in their zealous study of phenomena. They

urged, sometimes in an exaggerated manner, the superiority of modern

times in all that regards science, and the supreme and sole importance

of facts in scientific investigations. There prevailed among them also

a lofty and dignified tone of speaking of the condition and prospects

of science, such as we are accustomed to admire in the Verulamian

writings; for this, in a less degree, is epidemic among those who a

little after his time speak of the new philosophy.

5. _Otto Guericke, &c._--I need not illustrate these characteristics

at any great length. I may as an example notice Otto Guericke's

Preface to his _Experimenta Magdeburgica_ (1670). He quotes a passage

from Kircher's Treatise on the Magnetic Art, in which the author

says, "Hence it appears how all philosophy, except it be supported by

experiments, is empty, fallacious, and useless; what monstrosities

philosophers, in other respects of the highest and subtlest genius,

may produce in philosophy by neglecting experiment. Thus Experience

alone is the Dissolver of Doubts, the Reconciler of Difficulties, the

sole Mistress of Truth, who holds a torch before us in obscurity,

unties our knots, teaches us the true causes of things." Guericke

himself reiterates the same remark, adding that "philosophers,

insisting upon their own thoughts and arguments merely, cannot come

to any sound conclusion respecting the natural constitution of the

world." Nor were the Cartesians slow in taking up the same train of

reflection. Thus Gilbert Clark who, in 1660, published[212] a defence

of Descartes' doctrine of a _plenum_ in the universe, speaks in a

tone which reminds us of Bacon, and indeed was very probably caught

from him: "Natural philosophy formerly consisted entirely of loose

and most doubtful controversies, carried on in high-sounding words,

fit rather to delude than to instruct men. But at last (by the favour

of the Deity) there shone forth some more divine intellects, who

taking as their counsellors reason and experience together, exhibited

a new method of philosophizing. Hence has been conceived a strong hope

that philosophers may embrace, not a shadow or empty image of Truth,

but Truth herself: and that Physiology (Physics) scattering these

controversies to the winds, will contract an alliance with Mathematics.

Yet this is hardly the work of one age; still less of one man. Yet let

not the mind despond, or doubt not that, one party of investigators

after another following the same method of philosophizing, at last,

under good auguries, the mysteries of nature being daily unlocked as

far as human feebleness will allow, Truth may at last appear in full,

and these nuptial torches may be lighted."

As another instance of the same kind, I may quote the preface to the

First volume of the Transactions of the Academy of Sciences at Paris:

"It is only since the present century," says the writer, "that we can

reckon the revival of Mathematics and Physics. M. Descartes and other

great men have laboured at this work with so much success, that in this

department of literature, the whole face of things has been changed.

Men have quitted a sterile system of physics, which for several

generations had been always at the same point; the reign of words

and terms is passed; men will have things; they establish principles

which they understand, they follow those principles; and thus they

make progress. Authority has ceased to have more weight than Reason:

that which was received without contradiction because it had been

long received, is now examined, and often rejected: and philosophers

have made it their business to consult, respecting natural things,

Nature herself rather than the Ancients." These had now become the

commonplaces of those who spoke concerning the course and method of the

Sciences.

6. _Hooke._--In England, as might be expected, the influence of

Francis Bacon was more directly visible. We find many writers, about

this time, repeating the truths which Bacon had proclaimed, and in

almost every case showing the same imperfections in their views

which we have noticed in him. We may take as an example of this

Hooke's Essay, entitled "A General Scheme or Idea of the present

state of Natural Philosophy, and how its defects may be remedied by

a Methodical proceeding in the making Experiments and collecting

Observations; whereby to compile a Natural History as a solid basis

for the superstructure of true Philosophy." This Essay may be looked

upon as an attempt to adapt the _Novum Organon_ to the age which

succeeded its publication. We have in this imitation, as in the

original, an enumeration of various mistakes and impediments which had

in preceding times prevented the progress of knowledge; exhortations

to experiment and observation as the only solid basis of Science; very

ingenious suggestions of trains of inquiry, and modes of pursuing them;

and a promise of obtaining scientific truths when facts have been

duly accumulated. This last part of his scheme the author calls _a

Philosophical Algebra_; and he appears to have imagined that it might

answer the purpose of finding unknown causes from known facts, by means

of certain regular processes, in the same manner as Common Algebra

finds unknown from known quantities. But this part of the plan appears

to have remained unexecuted. The suggestion of such a method was a

result of the Baconian notion that invention in a discoverer might be

dispensed with. We find Hooke adopting the phrases in which this notion

is implied: thus he speaks of the understanding as "being very prone to

run into the affirmative way of judging, and wanting patience to follow

and prosecute the negative way of inquiry, by rejection of disagreeing

natures." And he follows Bacon also in the error of attempting at

once to obtain from the facts the discovery of a "nature," instead of

investigating first the measures and the laws of phenomena. I return to

more general notices of the course of men's thoughts on this subject.

7. _Royal Society._--Those who associated themselves together for the

prosecution of science quoted Bacon as their leader, and exulted in the

progress made by the philosophy which proceeded upon his principles.

Thus in Oldenburg's Dedication of the Transactions of the Royal Society

of London for 1670, to Robert Boyle, he says; "I am informed by such as

well remember the best and worst days of the famous Lord Bacon, that

though he wrote his _Advancement of Learning_ and his _Instauratio

Magna_ in the time of his greatest power, yet his greatest reputation

rebounded first from the most intelligent foreigners in many parts

of Christendom:" and after speaking of his practical talents and his

public employments, he adds, "much more justly still may we wonder how,

without any great skill in Chemistry, without much pretence to the

Mathematics or Mechanics, without optic aids or other engines of late

invention, he should so much transcend the philosophers then living,

in judicious and clear instructions, in so many useful observations

and discoveries, I think I may say beyond the records of many ages."

And in the end of the Preface to the same volume, he speaks with

great exultation of the advance of science all over Europe, referring

undoubtedly to facts then familiar. "And now let envy snarl, it

cannot stop the wheels of active philosophy, in no part of the known

world;--not in France, either in Paris or in Caen;--not in Italy,

either in Rome, Naples, Milan, Florence, Venice, Bononia or Padua;--in

none of the Universities either on this or on that side of the seas,

Madrid and Lisbon, all the best spirits in Spain and Portugal, and

the spacious and remote dominions to them belonging;--the Imperial

Court and the Princes of Germany; the Northern Kings and their best

luminaries; and even the frozen Muscovite and Russian have all taken

the operative ferment: and it works high and prevails every way, to the

encouragement of all sincere lovers of knowledge and virtue."

Again, in the Preface for 1672, he pursues the same thought into

detail: "We must grant that in the last age, when operative philosophy

began to recover ground, and to tread on the heels of triumphant

Philology; emergent adventures and great successes were encountered by

dangerous oppositions and strong obstructions. Galilæus and others in

Italy suffered extremities for their celestial discoveries; and here

in England Sir Walter Raleigh, when he was in his greatest lustrous,

was notoriously slandered to have erected a school of atheism, because

he gave countenance to chemistry, to practical arts, and to curious

mechanical operations, and designed to form the best of them into

a college. And Queen Elizabeth's Gilbert was a long time esteemed

extravagant for his magnetisms; and Harvey for his diligent researches

in pursuance of the circulation of the blood. But when our renowned

Lord Bacon had demonstrated the methods for a perfect restoration

of all parts of real knowledge; and the generous and philosophical

Peireskius had, soon after, agitated in all parts to redeem the most

instructive antiquities, and to excite experimental essays and fresh

discoveries; the success became on a sudden stupendous; and effective

philosophy began to sparkle, and even to flow into beams of shining

light all over the world."

The formation of the Royal Society of London and of the Academy

of Sciences of Paris, from which proceeded the declamations just

quoted, were among many indications, belonging to this period, of

the importance which states as well as individuals had by this time

begun to attach to the cultivation of science. The English Society was

established almost immediately when the restoration of the monarchy

appeared to give a promise of tranquillity to the nation (in 1660), and

the French Academy very soon afterwards (in 1666). These measures were

very soon followed by the establishment of the Observatories of Paris

and Greenwich (in 1667 and 1675); which may be considered to be a kind

of public recognition of the astronomy of observation, as an object

on which it was the advantage and the duty of nations to bestow their

wealth.

8. _Bacon's New Atalantis._--When philosophers had their attention

turned to the boundless prospect of increase to the knowledge and

powers and pleasures of man which the cultivation of experimental

philosophy seemed to promise, it was natural that they should think of

devising institutions and associations by which such benefits might be

secured. Bacon had drawn a picture of a society organized with a view

to such purpose, in his fiction of the "New Atalantis." The imaginary

teacher who explains this institution to the inquiring traveller,

describes it by the name of _Solomon's House_; and says[213], "The end

of our foundation is the knowledge of causes and secret motions of

things; and the enlarging the bounds of the human empire to effecting

of things possible." And, as parts of this House, he describes caves

and wells, chambers and towers, baths and gardens, parks and pools,

dispensatories and furnaces, and many other contrivances, provided

for the purpose of making experiments of many kinds. He describes

also the various employments of the Fellows of this College, who take

a share in its researches. There are _merchants of light_, who bring

books and inventions from foreign countries; _depredators_, who gather

the experiments which exist in books; _mystery-men_, who collect the

experiments of the mechanical arts; _pioneers_ or _miners_, who invent

new experiments; and _compilers_, "who draw the experiments of the

former into titles and tables, to give the better light for the drawing

of observations and axioms out of them." There are also _dowry-men_ or

_benefactors_, that cast about how to draw out of the experiments of

their fellows things of use and practice for man's life; _lamps_, that

direct new experiments of a more penetrating light than the former;

_inoculators_, that execute the experiments so directed. Finally, there

are the _interpreters of nature_, that raise the former discoveries by

experiments into greater observations (that is, more general truths),

axioms and aphorisms. Upon this scheme we may remark, that fictitious

as it undisguisedly is, it still serves to exhibit very clearly some of

the main features of the author's philosophy:--namely, his steady view

of the necessity of ascending from facts to the most general truths

by several stages;--an exaggerated opinion of the aid that could be

derived in such a task from technical separation of the phenomena and a

distribution of them into tables;--a belief, probably incorrect, that

the offices of experimenter and interpreter may be entirely separated,

and pursued by different persons with a certainty of obtaining

success!--and a strong determination to make knowledge constantly

subservient to the uses of life.

9. _Cowley._--Another project of the same kind, less ambitious but

apparently more directed to practice, was published a little later

(1657) by another eminent man of letters in this country. I speak of

Cowley's "Proposition for the Advancement of Experimental Philosophy."

He suggests that a College should be established at a short distance

from London, endowed with a revenue of four thousand pounds, and

consisting of twenty professors with other members. The objects of the

labours of these professors he describes to be, first, to examine all

knowledge of nature delivered to us from former ages and to pronounce

it sound or worthless; second, to recover the lost inventions of the

ancients; third, to improve all arts that we now have; lastly, to

discover others that we yet have not. In this proposal we cannot help

marking the visible declension from Bacon's more philosophical view.

For we have here only a very vague indication of improving old arts

and discovering new, instead of the two clear Verulamian antitheses,

Experiments and Axioms deduced from them, on the one hand, and on the

other an ascent to general Laws, and a derivation, from these, of Arts

for daily use. Moreover the prominent place which Cowley has assigned

to the verifying the knowledge of former ages and recovering "the lost

inventions and drowned lands of the ancients," implies a disposition to

think too highly of traditionary knowledge; a weakness which Bacon's

scheme shows _him_ to have fully overcome. And thus it has been up to

the present day, that with all Bacon's mistakes, in the philosophy of

scientific method few have come up to him, and perhaps none have gone

beyond him.

Cowley exerted himself to do justice to the new philosophy in verse as

well as prose, and his Poem to the Royal Society expresses in a very

noble manner those views of the history and prospects of philosophy

which prevailed among the men by whom the Royal Society was founded.

The fertility and ingenuity of comparison which characterize Cowley's

poetry are well known; and these qualities are in this instance largely

employed for the embellishment of his subject. Many of the comparisons

which he exhibits are apt and striking. Philosophy is a ward whose

estate (human knowledge) is, in his nonage, kept from him by his

guardians and tutors; (a case which the ancient rhetoricians were fond

of taking as a subject of declamation;) and these wrong-doers retain

him in unjust tutelage and constraint for their own purposes; until

Bacon at last, a mighty man, arose,

(Whom a wise King, and Nature, chose

Lord Chancellor of both their laws,)

And boldly undertook the injured pupil's cause.

Again, Bacon is one who breaks a scarecrow Priapus which stands in the

garden of knowledge. Again, Bacon is one who, instead of a picture of

painted grapes, gives us real grapes from which we press "the thirsty

soul's refreshing wine." Again, Bacon is like Moses, who led the

Hebrews forth from the barren wilderness, and ascended Pisgah;--

Did on the very border stand

Of the blest promised land,

And from the mountain's top of his exalted wit

Saw it himself and showed us it.

The poet however adds, that Bacon discovered, but did not conquer

this new world; and that the men whom he addresses must subdue these

regions. These "champions" are then ingeniously compared to Gideon's

band:

Their old and empty pitchers first they brake,

And with their hands then lifted up the light.

There were still at this time some who sneered at or condemned the new

philosophy; but the tide of popular opinion was soon strongly in its

favour. I have elsewhere[214] noticed a pasquinade of the poet Boileau

in 1682, directed against the Aristotelians. At this time, and indeed

for long afterwards, the philosophers of France were Cartesians. The

English men of science, although partially and for a time they accepted

some of Descartes' opinions, for the most part carried on the reform

independently, and in pursuance of their own views. And they very soon

found a much greater leader than Descartes to place at their head, and

to take as their authority, so far as they acknowledged authority,

in their speculations. I speak of Newton, whose influence upon the

philosophy of science I must now consider.

10. _Barrow._--I will, however, first mention one other writer who may,

in more than one way, be regarded as the predecessor of Newton. I speak

of Isaac Barrow, whom Newton succeeded as Professor of Mathematics in

the University of Cambridge, and who in his mathematical speculations

approached very near to Newton's method of Fluxions. He afterwards

(in 1673) became Master of Trinity College, which office he held

till his death in 1677. But the passages which I shall quote belong

to an earlier period, (when Barrow was about 22 years old,) and may

be regarded as expressions of the opinions which were then current

among active-minded and studious young men. They manifest a complete

familiarity with the writings both of Bacon and of Descartes, and a

very just appreciation of both. The discourse of which I speak is

an academical exercise delivered in 1652, on the thesis _Cartesiana

hypothesis haud satisfacit præcipuis naturæ phænomenis_. By the

"Cartesian hypothesis," he does not mean the hypothesis that the

planets are moved by vortices of etherial matter: I believe that this

Cartesian tenet never had any disciples in England; it certainly

never took any hold of Cambridge. By the Cartesian hypothesis, Barrow

means the doctrine that all the phenomena of nature can be accounted

for by matter and motion; and allowing that the motions of the planets

are to be so accounted for, (which is Newtonian as well as Cartesian

doctrine,) he denies that the Cartesian hypothesis accounts for "the

generations, properties, and specific operations of animals, plants,

minerals, stones, and other natural bodies," in doing which he shows

a sound philosophical judgment. But among the parts of this discourse

most bearing on our present purpose are those where he mentions Bacon.

"Against Cartesius," he says, "I pit the chymists and others, but

especially as the foremost champion of this battle, our Verulam, a man

of great name and of great judgment, who condemned this philosophy

before it was born." "He," adds Barrow, "several times in his

_Organon_, warned men against all hypotheses of this kind, and noticed

beforehand that there was not much to be expected from those principles

which are brought into being by violent efforts of argumentation from

the brains of particular men: for that, as upon the phenomena of the

stars, various constructions of the heavens may be devised, so also

upon the phenomena of the Universe, still more dogmas may be founded

and constructed; and yet all such are mere inventions: and as many

philosophies of this kind as are or shall be extant, so many fictitious

and theatrical worlds are made." The reference is doubtless to Aphorism

LXII. of the First Book of the _Novum Organon_, in which Bacon is

speaking of his "Idols of the Theatre." After making the remark which

Barrow has adopted, Bacon adds, "Such theatrical fables have also

this in common with those of dramatic poets, that the dramatic story

is more regular and elegant than true histories are, and is made so

as to be agreeable." Barrow, having this in his mind, goes on to say:

"And though Cartesius has dressed up the stage of his theatre more

prettily than any other person, and made his drama more like history,

still he is not exempt from the like censure." And he then refers to

Cartesius's own declaration, that he did not learn his system from

things themselves, but tried to impose his own laws upon things; thus

inverting the order of true philosophy.

Other parts of Bacon's work to which Barrow refers are those where

he speaks of the Form, or Formal Cause of a body, and says that in

comparison with that, the Efficient Cause and the Material Cause are

things unimportant and superficial, and contribute little to true and

active science[215]. And again, his classification of the various

kinds of motions[216],--the motus libertatis, motus nexus, motus

continuitatis, motus ad lucrum, fugæ, unionis, congregationis; and the

explanation of electrical attraction (about which Gilbert and others

had written) as _motus ad lucrum_.

These passages show that Barrow had read the _Novum Organon_ in a

careful and intelligent manner, and presumed his Cambridge hearers to

be acquainted with the work. Nor is his judgment of Descartes less wise

and philosophical. He rejects, as we have seen, his system as a true

scheme of the universe, and condemns altogether his _à priori_ mode

of philosophizing; but this does not prevent his accepting Descartes'

real discoveries, and admiring the boldness and vigour of his attempts

to reform philosophy. There is, in Barrow's works, academic verse, as

well as prose, on the subject of the Cartesian hypothesis. In this,

Descartes himself is highly praised, though his doctrines are very

partially accepted. The writer says: "Pardon us, great Cartesius, if

the Muse resists you. Pardon! We follow you, Inquiring Spirit that you

are, while we reject your system. As you have taught us free thought,

and broken down the rule of tyranny, we undauntedly speculate, even in

opposition to you."

Descartes is even yet spoken of, especially by French writers, as the

person who first asserted and established the freedom of inquiry which

is the boast of modern philosophy; but this is said with reference to

metaphysics, not to physics. In physical philosophy, though he caught

hold of some of the discoveries which were then coming into view, the

method in which he reasoned or professed to reason was altogether

vicious; and was, as I have already said, an attempt to undo what

the reformers, both theoretical and practical, had been doing:--to

discredit the philosophy of experience, and to restore the reign of _à

priori_ systems.

It was, however, now, too late to make any such attempt; and nothing

came of it to interrupt the progress of a better philosophy of

discovery.

FOOTNOTES:

[Footnote 200: _Anatomical Exercitations concerning the Generation of

Living Creatures_, 1653. Preface.]

[Footnote 201: He used similar expressions in conversation. George Ent,

who edited his _Generation of Animals_, visited him, "at that time

residing not far from the city; and found him very intent upon the

perscrutation of nature's works, and with a countenance as cheerful,

as mind unperturbed; Democritus-like, chiefly searching into the cause

of natural things." In the course of conversation the writer said, "It

hath always been your choice about the secrets of Nature, to consult

Nature herself." "'Tis true," replied he; "and I have constantly been

of opinion that from thence we might acquire not only the knowledge

of those less considerable secrets of Nature, but even a certain

admiration of that Supreme Essence, the Creator. And though I have

ever been ready to acknowledge, that many things have been discovered

by learned men of former times; yet do I still believe that the number

of those which remain yet concealed in the darkness of impervestigable

Nature is much greater. Nay, I cannot forbear to wonder, and sometimes

smile at those, who persuade themselves, that all things were so

consummately and absolutely delivered by Aristotle, Galen, or some

other great name, as that nothing was left to the superaddition of any

that succeeded."]

[Footnote 202: Lib. i. c. 2, 3.]

[Footnote 203: _Anal. Post._ ii.]

[Footnote 204: Pars iii. p. 45.]

[Footnote 205: See _Hist. Ind. Sc._ b. vi. c. ii.]

[Footnote 206: Cap. i. ii.]

[Footnote 207: _Hist. Ind. Sc._ b. ix. c. ii.]

[Footnote 208: _Meteorum_, c. viii. p. 187.]

[Footnote 209: Mackintosh, _Dissertation on Ethical Science_.]

[Footnote 210: _Hist. Ind. Sc._ b. vii. c. i.]

[Footnote 211: Castelli, Torricelli, Viviani, Baliani, Gassendi,

Mersenne, Borelli, Cavalleri.]

[Footnote 212: _De Plenitudine Mundi, in qua defenditur Cartesiana

Philosophia contra sententias Francisci Baconi, Th. Hobbii et Sethi

Wardi._]

[Footnote 213: Bacon's _Works_, vol. ii. 111.]

[Footnote 214: _Hist. Ind. Sc._ b. vii. c. i.]

[Footnote 215: _Nov. Org._ lib. ii. Aph. 2.]

[Footnote 216: _Ib._ lib. ii. Aph. 45.]

CHAPTER XVIII.

NEWTON.

1. Bold and extensive as had been the anticipations of those whose

minds were excited by the promise of the new philosophy, the

discoveries of Newton respecting the mechanics of the universe,

brought into view truths more general and profound than those earlier

philosophers had hoped or imagined. With these vast accessions to human

knowledge, men's thoughts were again set in action; and philosophers

made earnest and various attempts to draw, from these extraordinary

advances in science, the true moral with regard to the conduct and

limits of the human understanding. They not only endeavoured to verify

and illustrate, by these new portions of science, what had recently

been taught concerning the methods of obtaining sound knowledge;

but they were also led to speculate concerning many new and more

interesting questions relating to this subject. They saw, for the first

time, or at least far more clearly than before, the distinction between

the inquiry into the _laws_, and into the _causes_ of phenomena. They

were tempted to ask, how far the discovery of causes could be carried;

and whether it would soon reach, or clearly point to, the ultimate

cause. They were driven to consider whether the properties which they

discovered were essential properties of all matter, necessarily and

primarily involved in its essence, though revealed to us at a late

period by their derivative effects. These questions even now agitate

the thoughts of speculative men. Some of them have already, in this

work, been discussed, or arranged in the places which our view of the

philosophy of these subjects assigns to them. But we must here notice

them as they occurred to Newton himself and his immediate followers.

2. The general Baconian notion of the method of philosophizing,--that

it consists in ascending from phenomena, through various stages of

generalization, to truths of the highest order,--received, in Newton's

discovery of the universal mutual gravitation of every particle of

matter, that pointed actual exemplification, for want of which it had

hitherto been almost overlooked, or at least very vaguely understood.

That great truth, and the steps by which it was established, afford,

even now, by far the best example of the successive ascent, from one

scientific truth to another,--of the repeated transition from less to

more general propositions,--which we can yet produce; as may be seen

in the Table which exhibits the relation of these steps in Book II. of

the _Novum Organon Renovatum_. Newton himself did not fail to recognize

this feature in the truths which he exhibited. Thus he says[217], "By

the way of Analysis we proceed from compounds to ingredients, as from

motions to the forces producing them; and in general, from effects

to their causes, and from particular causes to more general ones,

till the argument ends in the most general." And in like manner in

another Query[218]: "The main business of natural philosophy is to

argue from phenomena without feigning hypotheses, and to deduce causes

from effects, till we come to the First Cause, which is certainly not

mechanical."

3. Newton appears to have had a horror of the term _hypothesis_,

which probably arose from his acquaintance with the rash and illicit

general assumptions of Descartes. Thus in the passage just quoted,

after declaring that gravity must have some other cause than matter,

he says, "Later philosophers banish the consideration of such a cause

out of Natural Philosophy, feigning hypotheses for explaining all

things mechanically, and referring other causes to metaphysics." In the

celebrated Scholium at the end of the _Principia_ he says, "Whatever

is not deduced from the phenomena, is to be termed _hypothesis_;

and hypotheses, whether metaphysical or physical, or occult causes,

or mechanical, have no place in experimental philosophy. In this

philosophy, propositions are deduced from phenomena, and rendered

general by induction." And in another place, he arrests the course

of his own suggestions, saying, "Verum hypotheses non fingo." I have

already attempted to show that this is, in reality, a superstitious and

self-destructive spirit of speculation. Some hypotheses are necessary,

in order to connect the facts which are observed; some new principle

of unity must be applied to the phenomena, before induction can be

attempted. What is requisite is, that the hypothesis should be close

to the facts, and not connected with them by the intermediation of

other arbitrary and untried facts; and that the philosopher should be

ready to resign it as soon as the facts refuse to confirm it. We have

seen in the _History_[219], that it was by such a use of hypotheses,

that both Newton himself, and Kepler, on whose discoveries those of

Newton were based, made their discoveries. The suppositions of a force

tending to the sun and varying inversely as the square of the distance;

of a mutual force between all the bodies of the solar system; of the

force of each body arising from the attraction of all its parts; not to

mention others, also propounded by Newton,--were all hypotheses before

they were verified as theories. It is related that when Newton was

asked how it was that he saw into the laws of nature so much further

than other men, he replied, that if it were so, it resulted from his

keeping his thoughts steadily occupied upon the subject which was to be

thus penetrated. But what is this occupation of the thoughts, if it be

not the process of keeping the phenomena clearly in view, and trying,

one after another, all the plausible hypotheses which seem likely to

connect them, till at last the true law is discovered? Hypotheses so

used are a necessary element of discovery.

4. With regard to the details of the process of discovery, Newton

has given us some of his views, which are well worthy of notice, on

account of their coming from him; and which are real additions to the

philosophy of this subject. He speaks repeatedly of the _analysis_

and _synthesis_ of observed facts; and thus marks certain steps in

scientific research, very important, and not, I think, clearly pointed

out by his predecessors. Thus he says[220], "As in Mathematics, so

in Natural Philosophy, the investigation of difficult things by the

method of analysis ought ever to precede the method of composition.

This analysis consists in making experiments and observations, and

in drawing general conclusions from them by induction, and admitting

of no objections against the conclusions, but such as are taken from

experiments or other certain truths. And although the arguing from

experiments and observations by induction be no demonstration of

general conclusions; yet it is the best way of arguing which the nature

of things admits of, and may be looked upon as so much the stronger,

by how much the induction is more general." And he then observes, as

we have quoted above, that by this way of analysis we proceed from

compounds to ingredients, from motions to forces, from effects to

causes, and from less to more general causes. The _analysis_ here

spoken of includes the steps which in _our_ Novum Organon we call the

_decomposition_ of facts, the exact _observation_ and _measurement_

of the phenomena, and the _colligation_ of facts; the necessary

intermediate step, the _selection_ and _explication_ of the appropriate

conception, being passed over by Newton, in the fear of seeming to

encourage the fabrication of hypotheses. The _synthesis_ of which

Newton here speaks consists of those steps of _deductive reasoning_,

proceeding from the conception once assumed, which are requisite for

the comparison of its consequences with the observed facts. This, his

statement of the process of research, is, as far as it goes, perfectly

exact.

5. In speaking of Newton's precepts on the subject, we are naturally

led to the celebrated "Rules of Philosophizing," inserted in the second

edition of the _Principia_. These rules have generally been quoted and

commented on with an almost unquestioning reverence. Such Rules, coming

from such an authority, cannot fail to be highly interesting to us; but

at the same time, we cannot here evade the necessity of scrutinizing

their truth and value, according to the principles which our survey of

this subject has brought into view. The Rules stand at the beginning of

that part of the _Principia_ (the Third Book) in which he infers the

mutual gravitation of the sun, moon, planets, and all parts of each.

They are as follows:

"Rule I. We are not to admit other causes of natural things than such

as both are true, and suffice for explaining their phenomena.

"Rule II. Natural effects of the same kind are to be referred to the

same causes, as far as can be done.

"Rule III. The qualities of bodies which cannot be increased or

diminished in intensity, and which belong to all bodies in which we

can institute experiments, are to be held for qualities of all bodies

whatever.

"Rule IV. In experimental philosophy, propositions collected from

phenomena by induction, are to be held as true either accurately

or approximately, notwithstanding contrary hypotheses; till other

phenomena occur by which they may be rendered either more accurate or

liable to exception."

In considering these Rules, we cannot help remarking, in the first

place, that they are constructed with an intentional adaptation to

the case with which Newton has to deal,--the induction of Universal

Gravitation; and are intended to protect the reasonings before which

they stand. Thus the first Rule is designed to strengthen the inference

of gravitation from the celestial phenomena, by describing it as a

_vera causa_, a true cause; the second Rule countenances the doctrine

that the planetary motions are governed by mechanical forces, as

terrestrial motions are; the third rule appears intended to justify the

assertion of gravitation, as a _universal_ quality of bodies; and the

fourth contains, along with a general declaration of the authority of

induction, the author's usual protest against hypotheses, levelled at

the Cartesian hypotheses especially.

6. _Of the First Rule._--We, however, must consider these Rules in

their general application, in which point of view they have often been

referred to, and have had very great authority allowed them. One of the

points which has been most discussed, is that maxim which requires that

the causes of phenomena which we assign should be true causes, _veræ

causæ_. Of course this does not mean that they should be _the_ true

or right cause; for although it is the philosopher's aim to discover

such causes, he would be little aided in his search of truth, by being

told that it is truth which he is to seek. The rule has generally

been understood to prescribe that in attempting to account for any

class of phenomena, we must assume such causes only, as _from other

considerations_, we know to exist. Thus gravity, which was employed in

explaining the motions of the moon and planets, was already known to

exist and operate at the earth's surface.

Now the Rule thus interpreted is, I conceive, an injurious limitation

of the field of induction. For it forbids us to look for a cause,

except among the causes with which we are already familiar. But if we

follow this rule, how shall we ever become acquainted with any new

cause? Or how do we know that the phenomena which we contemplate do

really arise from some cause which we already truly know? If they do

not, must we still insist upon making them depend upon some of our

known causes; or must we abandon the study of them altogether? Must we,

for example, resolve to refer the action of radiant heat to the air,

rather than to any peculiar fluid or ether, because the former is known

to exist, the latter is merely assumed for the purpose of explanation?

But why should we do this? Why should we not endeavour to learn the

cause from the effects, even if it be not already known to us? We

can infer causes, which are new when we first become acquainted with

them. Chemical Forces, Optical Forces, Vital Forces, are known to us

only by chemical and optical and vital phenomena; must we, therefore,

reject their existence or abandon their study? They do not conform to

the double condition, that they shall be sufficient and _also_ real:

they are true, only so far as they explain the facts, but are they,

therefore, unintelligible or useless? Are they not highly important

and instructive subjects of speculation? And if the gravitation which

rules the motions of the planets had not existed at the earth's

surface;--if it had been there masked and concealed by the superior

effect of magnetism, or some other extraneous force,--might not Newton

still have inferred, from Kepler's laws, the tendency of the planets to

the sun; and from their perturbations, their tendency to each other?

His discoveries would still have been immense, if the cause which he

assigned had not been a _vera causa_ in the sense now contemplated.

7. But what do we mean by calling gravity a "true cause"? How do

we learn its reality? Of course, by its effects, with which we are

familiar;--by the weight and fall of bodies about us. These strike even

the most careless observer. No one can fail to see that all bodies

which we come in contact with are heavy;--that gravity acts in our

neighbourhood here upon earth. Hence, it may be said, this cause is at

any rate a true cause, whether it explains the celestial phenomena or

not.

But if this be what is meant by a _vera causa_, it appears strange to

require that in all cases we should find such a one to account for

all classes of phenomena. Is it reasonable or prudent to demand that

we shall reduce every set of phenomena, however minute, or abstruse,

or complicated, to causes so obviously existing as to strike the most

incurious, and to be familiar among men? How can we expect to find

_such veræ causæ_ for the delicate and recondite phenomena which

an exact and skilful observer detects in chemical, or optical, or

electrical experiments? The facts themselves are too fine for vulgar

apprehension; their relations, their symmetries, their measures require

a previous discipline to understand them. How then can their causes be

found among those agencies with which the common unscientific herd of

mankind are familiar? What likelihood is there that causes held for

real by such persons, shall explain facts which such persons cannot see

or cannot understand?

Again: if we give authority to such a rule, and require that the causes

by which science explains the facts which she notes and measures and

analyses, shall be causes which men, without any special study, have

already come to believe in, from the effects which they casually

see around them, what is this, except to make our first rude and

unscientific persuasions the criterion and test of our most laborious

and thoughtful inferences? What is it, but to give to ignorance and

thoughtlessness the right of pronouncing upon the convictions of

intense study and long-disciplined thought? "Electrical atmospheres"

surrounding electrized bodies, were at one time held to be a "true

cause" of the effects which such bodies produce. These atmospheres, it

was said, are obvious to the senses; we feel them like a spider's web

on the hands and face. Æpinus had to answer such persons, by proving

that there are no atmospheres, no effluvia, but only repulsion. He

thus, for a _true cause_ in the vulgar sense of the term, substituted

an _hypothesis_; yet who doubts that what he did was an advance in the

science of electricity?

8. Perhaps some persons may be disposed to say, that Newton's Rule

does not enjoin us to take those causes only which we clearly know, or

suppose we know, to be really existing and operating, but only causes

_of such kinds_ as we have already satisfied ourselves do exist in

nature. It may be urged that we are entitled to infer that the planets

are governed in their motions by an attractive force, because we find,

in the bodies immediately subject to observation and experiment,

that such motions are produced by attractive forces, for example, by

that of the earth. It may be said that we might on similar grounds

infer forces which unite particles of chemical compounds, or deflect

particles of light, because we see adhesion and deflection produced by

forces.

But it is easy to show that the Rule, thus laxly understood, loses all

significance. It prohibits no hypothesis; for all hypotheses suppose

causes _such as_, in some case or other, we have seen in action. No

one would think of explaining phenomena by referring them to forces

and agencies altogether different from any which are known; for on

this supposition, how could he pretend to reason about the effects

of the assumed causes, or undertake to prove that they would explain

the facts? Some close similarity with some known kind of cause is

requisite, in order that the hypothesis may have the appearance of

an explanation. No forces, or virtues, or sympathies, or fluids, or

ethers, would be excluded by _this_ interpretation of _veræ causæ_.

Least of all, would such an interpretation reject the Cartesian

hypothesis of vortices; which undoubtedly, as I conceive, Newton

intended to condemn by his Rule. For that _such_ a case as a whirling

fluid, carrying bodies round a centre in orbits, does occur, is too

obvious to require proof. Every eddying stream, or blast that twirls

the dust in the road, exhibits examples of such action, and would

justify the assumption of the vortices which carry the planets in their

courses; as indeed, without doubt, such facts suggested the Cartesian

explanation of the solar system. The vortices, in this mode of

considering the subject, are at the least as _real_ a cause of motion

as gravity itself.

9. Thus the Rule which enjoins "true causes," is nugatory, if we take

_veræ causæ_ in the extended sense of any causes of a real _kind_,

and unphilosophical, if we understand the term of _those very_ causes

which we familiarly suppose to exist. But it may be said that we are to

designate as "true causes," not those which are collected in a loose,

confused and precarious manner, by undisciplined minds, from obvious

phenomena, but those which are justly and rigorously inferred. Such

a cause, it may be added, gravity is; for the facts of the downward

pressures and downward motions of bodies at the earth's surface lead

us, by the plainest and strictest induction, to the assertion of such

a force. Now to this interpretation of the Rule there is no objection;

but then, it must be observed, that on this view, terrestrial gravity

is inferred by the same process as celestial gravitation; and the

cause is no more entitled to be called "true," because it is obtained

from the former, than because it is obtained from the latter class of

facts. We thus obtain an intelligible and tenable explanation of a

_vera causa_; but then, by this explanation, its _verity_ ceases to be

distinguishable from its other condition, that it "suffices for the

explanation of the phenomena." The assumption of universal gravitation

accounts for the fall of a stone; it also accounts for the revolutions

of the Moon or of Saturn; but since both these explanations are of the

same kind, we cannot with justice make the one a criterion or condition

of the admissibility of the other.

10. But still, the Rule, so understood, is so far from being unmeaning

or frivolous, that it expresses one of the most important tests which

can be given of a sound physical theory. It is true, the explanation of

one set of facts may be of the same nature as the explanation of the

other class: but then, that the cause explains _both_ classes, gives it

a very different claim upon our attention and assent from that which

it would have if it explained one class only. The very circumstance

that the two explanations coincide, is a most weighty presumption in

their favour. It is the testimony of two witnesses in behalf of the

hypothesis; and in proportion as these two witnesses are separate

and independent, the conviction produced by their agreement is more

and more complete. When the explanation of two kinds of phenomena,

distinct, and not apparently connected, leads us to the same cause,

such a coincidence does give a reality to the cause, which it has

not while it merely accounts for those appearances which suggested

the supposition. This coincidence of propositions inferred from

separate classes of facts, is exactly what we noticed in the _Novum

Organon Renovatum_ (b. ii. c. 5, sect. 3), as one of the most decisive

characteristics of a true theory, under the name of _Consilience of

Inductions_.

That Newton's First Rule of Philosophizing, so understood, authorizes

the inferences which he himself made, is really the ground on which

they are so firmly believed by philosophers. Thus when the doctrine

of a gravity varying inversely as the square of the distance from

the body, accounted at the same time for the relations of times and

distances in the planetary orbits and for the amount of the moon's

deflection from the tangent of her orbit, such a doctrine became most

convincing: or again, when the doctrine of the universal gravitation of

all parts of matter, which explained so admirably the inequalities of

the moon's motions, also gave a satisfactory account of a phenomenon

utterly different, the precession of the equinoxes. And of the same

kind is the evidence in favour of the undulatory theory of light, when

the assumption of the length of an undulation, to which we are led by

the colours of thin plates, is found to be identical with that length

which explains the phenomena of diffraction; or when the hypothesis of

transverse vibrations, suggested by the facts of polarization, explains

also the laws of double refraction. When such a convergence of two

trains of induction points to the same spot, we can no longer suspect

that we are wrong. Such an accumulation of proof really persuades us

that we have to do with a _vera causa_. And if this kind of proof be

multiplied;--if we again find other facts of a sort uncontemplated in

framing our hypothesis, but yet clearly accounted for when we have

adopted the supposition;--we are still further confirmed in our belief;

and by such accumulation of proof we may be so far satisfied, as to

believe without conceiving it possible to doubt. In this case, when the

validity of the opinion adopted by us has been repeatedly confirmed by

its sufficiency in unforeseen cases, so that all doubt is removed and

forgotten, the theoretical cause takes its place among the realities

of the world, and becomes _a true cause_.

11. Newton's Rule then, to avoid mistakes, might be thus expressed:

That "we may, provisorily, assume such hypothetical cause as will

account for any given class of natural phenomena; but that when two

different classes of facts lead us to the same hypothesis, we may hold

it to be a _true cause_." And this Rule will rarely or never mislead

us. There are no instances, in which a doctrine recommended in this

manner has afterwards been discovered to be false. There have been

hypotheses which have explained many phenomena, and kept their ground

long, and have afterwards been rejected. But these have been hypotheses

which explained only one class of phenomena; and their fall took place

when another kind of facts was examined and brought into conflict with

the former. Thus the system of eccentrics and epicycles accounted

for all the observed _motions_ of the planets, and was the means of

expressing and transmitting all astronomical knowledge for two thousand

years. But then, how was it overthrown? By considering the _distances_

as well as motions of the heavenly bodies. Here was a second class of

facts; and when the system was adjusted so as to agree with the one

class, it was at variance with the other. These cycles and epicycles

could not be true, because they could not be made a just representation

of the facts. But if the measures of distance as well as of position

had conspired in pointing out the cycles and epicycles, as the paths of

the planets, the paths so determined could not have been otherwise than

their real paths; and the epicyclical theory would have been, at least

geometrically, true.

12. _Of the Second Rule._--Newton's Second Rule directs that "natural

events of the _same kind_ are to be referred to the _same causes_, so

far as can be done." Such a precept at first appears to help us but

little; for all systems, however little solid, profess to conform to

such a rule. When any theorist undertakes to explain a class of facts,

he assigns causes which, according to him, will by their natural

action, as seen in other cases, produce the effects in question. The

events which he accounts for by his hypothetical cause, are, he holds,

of the same kind as those which such a cause is known to produce.

Kepler, in ascribing the planetary motions to magnetism, Descartes, in

explaining them by means of vortices, held that they were referring

celestial motions to the causes which give rise to terrestrial motions

of the same kind. The question is, _Are_ the effects of the same kind?

This once settled, there will be no question about the propriety of

assigning them to the same cause. But the difficulty is, to determine

_when_ events are of the same kind. Are the motions of the planets of

the same kind with the motion of a body moving freely in a curvilinear

path, or do they not rather resemble the motion of a floating body

swept round by a whirling current? The Newtonian and the Cartesian

answered this question differently. How then can we apply this Rule

with any advantage?

13. To this we reply, that there is no way of escaping this uncertainty

and ambiguity, but by obtaining a clear possession of the ideas which

our hypothesis involves, and by reasoning rigorously from them. Newton

asserts that the planets move in free paths, acted on by certain

forces. The most exact calculation gives the closest agreement of

the results of this hypothesis with the facts. Descartes asserts

that the planets are carried round by a fluid. The more rigorously

the conceptions of force and the laws of motion are applied to this

hypothesis, the more signal is its failure in reconciling the facts

to one another. Without such calculation, we can come to no decision

between the two hypotheses. If the Newtonian hold that the motions

of the planets are _evidently_ of the _same kind_ as those of a body

describing a curve in free space, and therefore, like that, to be

explained by a force acting upon the body; the Cartesian denies that

the planets do move in free space. They are, he maintains, immersed

in a plenum. It is only when it appears that comets pass through this

plenum in all directions with no impediment, and that no possible form

and motion of its whirlpools can explain the forces and motions which

are observed in the solar system, that he is compelled to allow the

Newtonian's classification of events of the _same kind_.

Thus it does not appear that this Rule of Newton can be interpreted in

any distinct and positive manner, otherwise than as enjoining that, in

the task of induction, we employ clear ideas, rigorous reasoning, and

close and fair comparison of the results of the hypothesis with the

facts. These are, no doubt, important and fundamental conditions of a

just induction; but in this injunction we find no peculiar or technical

criterion by which we may satisfy ourselves that we are right, or

detect our errors. Still, of such general prudential rules, none can be

more wise than one which thus, in the task of connecting facts by means

of ideas, recommends that the ideas be clear, the facts, correct, and

the chain of reasoning which connects them, without a flaw.

14. _Of the Third Rule._--The Third Rule, that "qualities which are

observed without exception be held to be universal," as I have already

said, seems to be intended to authorize the assertion of gravitation

as a universal attribute of matter. We formerly stated, in treating of

Mechanical Ideas[221], that this application of such a Rule appears

to be a mode of reasoning far from conclusive. The assertion of the

universality of any property of bodies must be grounded upon the

reason of the case, and not upon any arbitrary maxim. Is it intended

by this Rule to prohibit any further examination how far gravity is

an original property of matter, and how far it may be resolved into

the result of other agencies? We know perfectly well that this was not

Newton's intention; since the cause of gravity was a point which he

proposed to himself as a subject of inquiry. It would certainly be very

unphilosophical to pretend, by this Rule of Philosophizing, to prejudge

the question of such hypotheses as that of Mosotti, That gravity is

the excess of the electrical attraction over electrical repulsion, and

yet to adopt this hypothesis, would be to suppose electrical forces

more truly universal than gravity; for according to the hypothesis,

gravity, being the inequality of the attraction and repulsion, is only

an accidental and partial relation of these forces. Nor would it be

allowable to urge this Rule as a reason of assuming that double stars

are attracted to each other by a force varying according to the inverse

square of the distance; without examining, as Herschel and others have

done, the orbits which they really describe. But if the Rule is not

available in such cases, what is its real value and authority? and in

what cases are they exemplified?

15. In a former work[222], it was shown that the fundamental laws of

motion, and the properties of matter which these involve, are, after a

full consideration of the subject, unavoidably assumed as universally

true. It was further shown, that although our knowledge of these laws

and properties be gathered from experience, we are strongly impelled,

(some philosophers think, authorized,) to look upon these as not only

universally, but necessarily true. It was also stated, that the law

of gravitation, though its universality may be deemed probable, does

not apparently involve the same necessity as the fundamental laws of

motion. But it was pointed out that these are some of the most abstruse

and difficult questions of the whole of philosophy; involving the

profound, perhaps insoluble, problem of the identity or diversity of

Ideas and Things. It cannot, therefore, be deemed philosophical to

cut these Gordian knots by peremptory maxims, which encourage us to

decide without rendering a reason. Moreover, it appears clear that

the reason which is rendered for this Rule by the Newtonians is quite

untenable; namely, that we know extension, hardness, and inertia, to

be universal qualities of bodies by experience alone, and that we have

the same evidence of experience for the universality of gravitation.

We have already observed that we cannot, with any propriety, say that

we _find_ by experience all bodies are extended. This could not be a

just assertion, unless we conceive the possibility of our finding the

contrary. But who can conceive our finding by experience some bodies

which are not extended? It appears, then, that the reason given for

the Third Rule of Newton involves a mistake respecting the nature and

authority of experience. And the Rule itself cannot be applied without

attempting to decide, by the casual limits of observation, questions

which necessarily depend upon the relations of ideas.

16. _Of the Fourth Rule._--Newton's Fourth Rule is, that "Propositions

collected from phenomena by induction, shall be held to be true,

notwithstanding contrary hypotheses; but shall be liable to be rendered

more accurate, or to have their exceptions pointed out, by additional

study of phenomena." This Rule contains little more than a general

assertion of the authority of induction, accompanied by Newton's usual

protest against hypotheses.

The really valuable part of the Fourth Rule is that which implies

that a constant verification, and, if necessary, rectification,

of truths discovered by induction, should go on in the scientific

world. Even when the law is, or appears to be, most certainly exact

and universal, it should be constantly exhibited to us afresh in the

form of experience and observation. This is necessary, in order to

discover exceptions and modifications if such exist: and if the law be

rigorously true, the contemplation of it, as exemplified in the world

of phenomena, will best give us that clear apprehension of its bearings

which may lead us to see the ground of its truth.

The concluding clause of this Fourth Rule appears, at first, to

imply that all inductive propositions are to be considered as merely

provisional and limited, and never secure from exception. But to judge

thus would be to underrate the stability and generality of scientific

truths; for what man of science can suppose that we shall hereafter

discover exceptions to the universal gravitation of all parts of the

solar system? And it is plain that the author did not intend the

restriction to be applied so rigorously; for in the Third Rule, as

we have just seen, he authorizes us to infer universal properties of

matter from observation, and carries the liberty of inductive inference

to its full extent. The Third Rule appears to encourage us to assert a

law to be universal, even in cases in which it has not been tried; the

Fourth Rule seems to warn us that the law may be inaccurate, even in

cases in which it has been tried. Nor is either of these suggestions

erroneous; but both the universality and the rigorous accuracy of our

laws are proved by reference to Ideas rather than to Experience; a

truth, which, perhaps, the philosophers of Newton's time were somewhat

disposed to overlook.

17. The disposition to ascribe all our knowledge to Experience, appears

in Newton and the Newtonians by other indications; for instance, it

is seen in their extreme dislike to the ancient expressions by which

the principles and causes of phenomena were described, as the _occult

causes_ of the Schoolmen, and the _forms_ of the Aristotelians, which

had been adopted by Bacon. Newton says[223], that the particles of

matter not only possess inertia, but also active principles, as

gravity, fermentation, cohesion; he adds, "These principles I consider

not as Occult Qualities, supposed to result from the Specific Forms of

things, but as General Laws of Nature, by which the things themselves

are formed: their truth appearing to us by phenomena, though their

causes be not yet discovered. For these are manifest qualities, and

their causes only are occult. And the Aristotelians gave the name of

_occult qualities_, not to manifest qualities, but to such qualities

only as they supposed to lie hid in bodies, and to the unknown causes

of manifest effects: such as would be the causes of gravity, and of

magnetick and electrick attractions, and of fermentations, if we

should suppose that these forces or actions arose from qualities

unknown to us, and incapable of being discovered and made manifest.

Such occult qualities put a stop to the improvement of Natural

Philosophy, and therefore of late years have been rejected. To tell

us that every species of things is endowed with an occult specific

quality by which it acts and produces manifest effects, is to tell us

nothing: but to derive two or three general principles of motion from

phenomena, and afterwards to tell us how the properties and actions

of all corporeal things follow from these manifest principles, would

be a great step in philosophy, though the causes of those principles

were not yet discovered: and therefore I scruple not to propose the

principles of motion above maintained, they being of very general

extent, and leave their causes to be found out."

18. All that is here said is highly philosophical and valuable; but we

may observe that the investigation of _specific forms_ in the sense in

which some writers had used the phrase, was by no means a frivolous

or unmeaning object of inquiry. Bacon and others had used _form_ as

equivalent to _law_[224]. If we could ascertain that arrangement of

the particles of a crystal from which its external crystalline form

and other properties arise, this arrangement would be the _internal

form_ of the crystal. If the undulatory theory be true, the _form_ of

light is transverse vibrations: if the emission theory be maintained,

the _form_ of light is particles moving in straight lines, and

deflected by various forces. Both the terms, _form_ and _law_, imply

an ideal connexion of sensible phenomena; form supposes matter which

is moulded to the form; law supposes objects which are governed by

the law. The former term refers more precisely to existences, the

latter to occurrences. The latter term is now the more familiar, and

is, perhaps, the better metaphor: but the former also contains the

essential antithesis which belongs to the subject, and might be used in

expressing the same conclusions.

But occult causes, employed in the way in which Newton describes,

had certainly been very prejudicial to the progress of knowledge, by

stopping inquiry with a mere word. The absurdity of such pretended

explanations had not escaped ridicule. The pretended physician in the

comedy gives an example of an occult cause or virtue.

Mihi demandatur

A doctissimo Doctore

_Quare_ Opium facit dormire:

Et ego respondeo,

_Quia_ est in eo

_Virtus dormitiva_,

Cujus natura est sensus assoupire.

19. But the most valuable part of the view presented to us in

the quotation just given from Newton is the distinct separation,

already noticed as peculiarly brought into prominence by him, of the

determination of the _laws_ of phenomena, and the investigation of

their _causes_. The maxim, that the former inquiry must precede the

latter, and that if the general laws of facts be discovered, the result

is highly valuable, although the causes remain unknown, is extremely

important; and had not, I think, ever been so strongly and clearly

stated, till Newton both repeatedly promulgated the precept, and added

to it the weight of the most striking examples.

We have seen that Newton, along with views the most just and important

concerning the nature and methods of science, had something of the

tendency, prevalent in his time, to suspect or reject, at least

speculatively, all elements of knowledge except observation. This

tendency was, however, in him so corrected and restrained by his own

wonderful sagacity and mathematical habits, that it scarcely led to

any opinion which we might not safely adopt. But we must now consider

the cases in which this tendency operated in a more unbalanced manner,

and led to the assertion of doctrines which, if consistently followed,

would destroy the very foundations of all general and certain knowledge.

FOOTNOTES:

[Footnote 217: _Optics_, qu. 31, near the end.]

[Footnote 218: Qu. 28.]

[Footnote 219: _Hist. Ind. Sc._ b. v. and b. vii.]

[Footnote 220: _Optics_, qu. 31.]

[Footnote 221: _History of Ideas_, b. iii. c. x.]

[Footnote 222: _Ibid._ b. iii. c. ix. x. xi.]

[Footnote 223: _Opticks_, qu. 31.]

[Footnote 224: _Nov. Org._ l. ii. Aph. 2. "Licet enim in natura nihil

existet præter corpora individua, edentia actus puros individuos

ex lege; in doctrinis tamen illa ipsa lex, ejusque inquisitio, et

inventio, et explicatio, pro fundamento est tam ad sciendum quam ad

operandum. Eam autem _legem_, ejusque _paragraphos, formarum_ nomine

intelligimus; præsertim cum hoc vocabulum invaluerit, et familiariter

occurrat."

Aph. 17. "Eadem res est _forma_ calidi vel _forma_ luminis, et _lex_

calidi aut _lex_ luminis."]

CHAPTER XIX.

LOCKE AND HIS FRENCH FOLLOWERS.

1. In the constant opposition and struggle of the schools of

philosophy, which consider our Senses and our Ideas respectively,

as the principal sources of our knowledge, we have seen that at the

period of which we now treat, the tendency was to exalt the external

and disparage the internal element. The disposition to ascribe our

knowledge to observation alone, had already, in Bacon's time, led him

to dwell to a disproportionate degree upon that half of his subject;

and had tinged Newton's expressions, though it had not biassed his

practice. But this partiality soon assumed a more prominent shape,

becoming extreme in Locke, and extravagant in those who professed to

follow him.

Indeed Locke appears to owe his popularity and influence as a popular

writer mainly to his being one of the first to express, in a plain and

unhesitating manner, opinions which had for some time been ripening

in the minds of a large portion of the cultivated public. Hobbes had

already promulgated the main doctrines which Locke afterwards urged, on

the subject of the origin and nature of our knowledge: but in him these

doctrines were combined with offensive opinions on points of morals,

government, and religion, so that their access to general favour was

impeded: and it was to Locke that they were indebted for the extensive

influence which they soon after obtained. Locke owed this authority

mainly to the intellectual circumstances of the time. Although a writer

of great merit, he by no means possesses such metaphysical acuteness or

such philosophical largeness of view, or such a charm of writing, as

must necessarily give him the high place he has held in the literature

of Europe. But he came at a period when the reign of Ideas was

tottering to its fall. All the most active and ambitious spirits had

gone over to the new opinions, and were prepared to follow the fortunes

of the Philosophy of Experiment, then in the most prosperous and

brilliant condition, and full of still brighter promise. There were,

indeed, a few learned and thoughtful men who still remained faithful

to the empire of Ideas; partly, it may be, from a too fond attachment

to ancient systems; but partly, also, because they knew that there

were subjects of vast importance, in which experience did not form the

whole foundation of our knowledge. They knew, too, that many of the

plausible tenets of the new philosophy were revivals of fallacies which

had been discussed and refuted in ancient times. But the advocates of

mere experience came on with a vast store of weighty truth among their

artillery, and with the energy which the advance usually bestows. The

ideal system of philosophy could, for the present, make no effectual

resistance; Locke, by putting himself at the head of the assault,

became the hero of his day: and his name has been used as the watchword

of those who adhere to the philosophy of the senses up to our own times.

2. Locke himself did not assert the exclusive authority of the senses

in the extreme unmitigated manner in which some who call themselves

his disciples have done. But this is the common lot of the leaders

of revolutions, for they are usually bound by some ties of affection

and habit to the previous state of things, and would not destroy all

traces of that condition: while their followers attend, not to their

inconsistent wishes, but to the meaning of the revolution itself;

and carry out, to their genuine and complete results, the principles

which won the victory, and which have been brought out more sharp from

the conflict. Thus Locke himself does not assert that all our ideas

are derived from Sensation, but from Sensation _and Reflection_. But

it was easily seen that, in this assertion, two very heterogeneous

elements were conjoined: that while to pronounce Sensation the origin

of ideas, is a clear decided tenet, the acceptance or rejection of

which determines the general character of our philosophy; to make the

same declaration concerning Reflection, is in the highest degree vague

and ambiguous; since reflection may either be resolved into a mere

modification of sensation, as was done by one school, or may mean all

that the opposite school opposes to sensation, under the name of Ideas.

Hence the clear and strong impression which fastened upon men's minds,

and which does in fact represent all the systematic and consistent part

of Locke's philosophy, was, that in it all our ideas are represented as

derived from Sensation.

3. We need not spend much time in pointing out the inconsistencies into

which Locke fell; as all must fall into inconsistencies who recognize

no source of knowledge except the senses. Thus he maintains that our

Idea of Space is derived from the senses of sight and touch; our Idea

of Solidity from the touch alone. Our Notion of Substance is an unknown

support of unknown qualities, and is illustrated by the Indian fable

of the tortoise which supports the elephant, which supports the world.

Our Notion of Power or Cause is in like manner got from the senses.

And yet, though these ideas are thus mere fragments of our experience,

Locke does not hesitate to ascribe to them necessity and universality

when they occur in propositions. Thus he maintains the necessary truth

of geometrical properties: he asserts that the resistance arising from

solidity is absolutely insurmountable[225]; he conceives that nothing

short of Omnipotence can annihilate a particle of matter[226]; and he

has no misgivings in arguing upon the axiom that Every thing must have

a cause. He does not perceive that, upon his own account of the origin

of our knowledge, we can have no right to make any of these assertions.

If our knowledge of the truths which concern the external world were

wholly derived from experience, all that we could venture to say would

be,--that geometrical properties of figures are true _as far as we have

tried them_;--that we have seen _no example_ of a solid body being

reduced to occupy less space by pressure, or of a material substance

annihilated by natural means;--and that _wherever we have examined_,

we have found that every change has had a cause. Experience can never

entitle us to declare that what she has not seen is impossible; still

less, that things which she can not see are certain. Locke himself

intended to throw no doubt upon the certainty of either human or

divine knowledge; but his principles, when men discarded the temper in

which he applied them, and the checks to their misapplication which

he conceived that he had provided, easily led to a very comprehensive

skepticism. His doctrines tended to dislodge from their true bases the

most indisputable parts of knowledge; as, for example, pure and mixed

mathematics. It may well be supposed, therefore, that they shook the

foundations of many other parts of knowledge in the minds of common

thinkers.

It was not long before these consequences of the overthrow of

ideas showed themselves in the speculative world. I have already

in a previous work[227] mentioned Hume's skeptical inferences from

Locke's maxim, that we have no ideas except those which we acquire

by experience; and the doctrines set up in opposition to this by

the metaphysicians of Germany. I might trace the progress of the

sensational opinions in Britain till the reaction took place here

also: but they were so much more clearly and decidedly followed out in

France, that I shall pursue their history in that country.

4. _The French Followers of Locke, Condillac, &c._--Most of the

French writers who adopted Locke's leading doctrines, rejected the

"Reflection," which formed an anomalous part of his philosophy, and

declared that Sensation alone was the source of ideas. Among these

writers, Condillac was the most distinguished. He expressed the leading

tenet of their school in a clear and pointed manner by saying that "All

ideas are transformed sensations." We have already considered this

phrase[228], and need not here dwell upon it.

Opinions such as these tend to annihilate, as we have seen, one of the

two co-ordinate elements of our knowledge. Yet they were far from being

so prejudicial to the progress of science, or even of the philosophy

of science, as might have been anticipated. One reason of this was,

that they were practically corrected, especially among the cultivators

of Natural Philosophy, by the study of mathematics; for that study did

really supply all that was requisite on the ideal side of science, so

far as the ideas of space, time, and number, were concerned, and partly

also with regard to the idea of cause and some others. And the methods

of discovery, though the philosophy of them made no material advance,

were practically employed with so much activity, and in so many various

subjects, that a certain kind of prudence and skill in this employment

was very widely diffused.

5. _Importance of Language._--In one respect this school of

metaphysicians rendered a very valuable service to the philosophy of

science. They brought into prominent notice the great importance of

_words_ and _terms_ in the formation and progress of knowledge, and

pointed out that the office of language is not only to convey and

preserve our thoughts, but to perform the analysis in which reasoning

consists. They were led to this train of speculation, in a great

measure, by taking pure mathematical science as their standard example

of substantial knowledge. Condillac, rejecting, as we have said, almost

all those ideas on which universal and demonstrable truths must be

based, was still not at all disposed to question the reality of human

knowledge; but was, on the contrary, a zealous admirer of the evidence

and connexion which appear in those sciences which have the ideas of

space and number for their foundation, especially the latter. He looked

for the grounds of the certainty and reality of the knowledge which

these sciences contain; and found them, as he conceived, in the nature

of the _language_ which they employ. The _Signs_ which are used in

arithmetic and algebra enable us to keep steadily in view the identity

of the same quantity under all the forms which, by composition and

decomposition, it may be made to assume; and these Signs also not only

express the operations which are performed, but suggest the extension

of the operations according to analogy. Algebra, according to him,

is only a very perfect language; and language answers its purpose of

leading us to truth, by possessing the characteristics of algebra.

Words are the symbols of certain groups of impressions or facts; they

are so selected and applied as to exhibit the analogies which prevail

among these facts; and these analogies are the truths of which our

knowledge consists. "Every language is an analytical method; every

analytical method is a language[229];" these were the truths "alike new

and simple," as he held, which he conceived that he had demonstrated.

"The art of speaking, the art of writing, the art of reasoning, the

art of thinking, are only, at bottom, one and the same art[230]." Each

of these operations consists in a succession of analytical operations;

and words are the marks by which we are able to fix our minds upon the

steps of this analysis.

6. The analysis of our impressions and notions does in reality lead

to truth, not only in virtue of the identity of the whole with its

parts, as Condillac held, but also in virtue of certain Ideas which

govern the synthesis of our sensations, and which contain the elements

of universal truths, as we have all along endeavoured to show. But

although Condillac overlooked or rejected this doctrine, the importance

of words, as marking the successive steps of this synthesis and

analysis, is not less than he represented it to be. Every truth, once

established by induction from facts, when it is become familiar under

a brief and precise form of expression, becomes itself a fact; and is

capable of being employed, along with other facts of a like kind, as

the materials of fresh inductions. In this successive process, the

term, like the cord of a fagot, both binds together the facts which it

includes, and makes it possible to manage the assemblage as a single

thing. On occasion of most discoveries in science, the selection of a

technical term is an essential part of the proceeding. In the _History

of Science_, we have had numerous opportunities of remarking this; and

the List of technical terms given as an Index to that work, refers us,

by almost every word, to one such occasion. And these terms, which

thus have had so large a share in the formation of science, and which

constitute its language, do also offer the means of analyzing its

truths, each into its constituent truths; and these into facts more

special, till the original foundations of our most general propositions

are clearly exhibited. The relations of general and particular truths

are most evidently represented by the Inductive Tables given in

Book II. of the _Novum Organon Renovatum_. But each step in each of

these Tables has its proper form of expression, familiar among the

cultivators of science; and the analysis which our Tables display, is

commonly performed in men's minds, when it becomes necessary, by fixing

the attention successively upon a series of words, not upon the lines

of a Table. Language offers to the mind such a scale or ladder as the

Table offers to the eye; and since such Tables present to us, as we

have said, the Logic of Induction, that is, the formal conditions of

the soundness of our reasoning from facts, we may with propriety say

that a just analysis of the meaning of words is an essential portion of

Inductive Logic.

In saying this, we must not forget that a decomposition of general

truths into ideas, as well as into facts, belongs to our philosophy;

but the point we have here to remark, is the essential importance of

words to the latter of these processes. And this point had not ever

had its due weight assigned to it till the time of Condillac and other

followers of Locke, who pursued their speculations in the spirit I have

just described. The doctrine of the importance of terms is the most

considerable addition to the philosophy of science which has been made

since the time of Bacon[231].

7. _The French Encyclopedists._--The French _Encyclopédie_, published

in 1751, of which Diderot and Dalembert were the editors, may be

considered as representing the leading characters of European

philosophy during the greater part of the eighteenth century. The

writers in this work belong for the most part to the school of Locke

and Condillac; and we may make a few remarks upon them, in order to

bring into view one or two points in addition to what we have already

said of that school. The _Discours Préliminaire_, written by Dalembert,

is celebrated as containing a view of the origin of our knowledge, and

the connexion and classification of the sciences.

A tendency of the speculations of the Encyclopedists, as of the School

of Locke in general, is to reject all ideal principles of connexion

among facts, as something which experience, the only source of true

knowledge, does not give. Hence all certain knowledge consists only

in the recognition of the same thing under different aspects, or

different forms of expression. Axioms are not the result of an original

relation of ideas, but of the use, or it may be the abuse[232], of

words. In like manner, the propositions of Geometry are a series of

modifications,--of distortions, so to speak,--of one original truth;

much as if the proposition were stated in the successive forms of

expression presented by a language which was constantly growing more

and more artificial. Several of the sciences which rest upon physical

principles, that is, (says the writer,) truths of experience or simple

hypotheses, have only an experimental or hypothetical certainty.

Impenetrability added to the idea of extent is a mystery in addition:

the nature of motion is a riddle for philosophers: the metaphysical

principle of the laws of percussion is equally concealed from them. The

more profoundly they study the idea of matter and of the properties

which represent it, the more obscure this idea becomes; the more

completely does it escape them.

8. This is a very common style of reflection, even down to our own

times. I have endeavoured to show that concerning the Fundamental Ideas

of space, of force and resistance, of substance, external quality, and

the like, we know enough to make these Ideas the grounds of certain

and universal truths;--enough to supply us with axioms from which we

can demonstratively reason. If men wish for any other knowledge of

the nature of matter than that which ideas, and facts conformable to

ideas, give them, undoubtedly their desire will be frustrated, and

they will be left in a mysterious vacancy; for it does not appear

how such knowledge as they ask for could be knowledge at all. But in

reality, this complaint of our ignorance of the real nature of things

proceeds from the rejection of ideas, and the assumption of the senses

alone as the ground of knowledge. "Observation and calculation are

the only sources of truth:" this is the motto of the school of which

we now speak. And its import amounts to this:--that they reject all

ideas except the idea of number, and recognize the modifications which

parts undergo by addition and subtraction as the only modes in which

true propositions are generated. The laws of nature are assemblages of

facts: the truths of science are assertions of the identity of things

which are the same. "By the avowal of almost all philosophers," says

a writer of this school[233], "the most sublime truths, when once

simplified and reduced to their lowest terms, are converted into facts,

and thenceforth present to the mind only this proposition; the white is

white, the black is black."

These statements are true in what they positively assert, but they

involve error in the denial which by implication they convey. It

is true that observation and demonstration are the only sources of

scientific truth; but then, demonstration may be founded on other

grounds besides the elementary properties of number. It is true that

the theory of gravitation is but the assertion of a general fact; but

this is so, not because a sound theory does not involve ideas, but

because our apprehension of a fact does.

9. Another characteristic indication of the temper of the

Encyclopedists and of the age to which they belong, is the importance

by them assigned to those practical _Arts_ which minister to man's

comfort and convenience. Not only, in the body of the Encyclopedia, are

the Mechanical Arts placed side by side with the Sciences, and treated

at great length; but in the Preliminary Discourse, the preference

assigned to the liberal over the mechanical Arts is treated as a

prejudice[234], and the value of science is spoken of as measured

by its utility. "The discovery of the Mariner's Compass is not less

advantageous to the human race than the explanation of its properties

would be to physics.--Why should we not esteem those to whom we owe

the fusee and the escapement of watches as much as the inventors of

Algebra?" And in the classification of sciences which accompanies the

Discourse, the labours of artisans of all kinds have a place.

This classification of the various branches of science contained

in the Dissertation is often spoken of. It has for its basis the

classification proposed by Bacon, in which the parts of human knowledge

are arranged according to the faculties of the mind in which they

originate; and these faculties are taken, both by Bacon and by

Dalembert, as Memory, Reason, and Imagination. The insufficiency of

Bacon's arrangement as a scientific classification is so glaring, that

the adoption of it, with only superficial modifications, at the period

of the Encyclopedia, is a remarkable proof of the want of original

thought and real philosophy at the time of which we speak.

10. We need not trace further the opinion which derives all our

knowledge from the senses in its application to the philosophy of

Science. Its declared aim is to reduce all knowledge to the knowledge

of Facts; and it rejects all inquiries which involve the Idea of Cause,

and similar Ideas, describing them as "metaphysical," or in some other

damnatory way. It professes, indeed, to discard all Ideas; but, as we

have long ago seen, some Ideas or other are inevitably included even

in the simplest Facts. Accordingly the speculations of this school

are compelled to retain the relations of Position, Succession, Number

and Resemblance, which are rigorously ideal relations. The philosophy

of Sensation, in order to be consistent, ought to reject these Ideas

along with the rest, and to deny altogether the possibility of general

knowledge.

When the opinions of the Sensational School had gone to an extreme

length, a Reaction naturally began to take place in men's minds. Such

have been the alternations of opinion, from the earliest ages of human

speculation. Man may perhaps have existed in an original condition in

which he was only aware of the impressions of Sense; but his first

attempts to analyse his perceptions brought under his notice Ideas as

a separate element, essential to the existence of knowledge. Ideas

were thenceforth almost the sole subject of the study of philosophers;

of Plato and his disciples, professedly; of Aristotle, and still more

of the followers and commentators of Aristotle, practically. And this

continued till the time of Galileo, when the authority of the Senses

again began to be asserted; for it was shown by the great discoveries

which were then made, that the Senses had at least some share in

the promotion of knowledge. As discoveries more numerous and more

striking were supplied by Observation, the world gradually passed

over to the opinion that the share which had been ascribed to Ideas in

the formation of real knowledge was altogether a delusion, and that

Sensation alone was true. But when this was asserted as a general

doctrine, both its manifest falsity and its alarming consequences

roused men's minds, and made them recoil from the extreme point to

which they were approaching. Philosophy again oscillated back towards

Ideas; and over a great part of Europe, in the clearest and most

comprehensive minds, this regression from the dogmas of the Sensational

School is at present the prevailing movement. We shall conclude our

review by noticing a few indications of this state of things.

FOOTNOTES:

[Footnote 225: _Essay_, b. xi. c. iv. sect. 3.]

[Footnote 226: _Ibid._ c. xiii. sect. 22.]

[Footnote 227: _History of Ideas_, b. iii. c. iii. Modern Opinions

respecting the Idea of Cause.]

[Footnote 228: _Ibid._ b. i. c. iv.]

[Footnote 229: _Langue des Calculs_, p. 1.]

[Footnote 230: _Grammaire_, p. xxxvi.]

[Footnote 231: Since the selection and construction of terms is thus

a matter of so much consequence in the formation of science, it is

proper that systematic rules, founded upon sound principles, should be

laid down for the performance of this operation. Some such rules are

accordingly suggested in b. iv. of the _Nov. Org. Ren._]

[Footnote 232: _Disc. Prélim._ p. viii.]

[Footnote 233: Helvetius _Sur l'Homme_, c. xxiii.]

[Footnote 234: P. xiii.]