PART I.

SELECTIONS FROM THE PRINCIPLES OF PHILOSOPHY

OF

RENE DESCARTES

(1596-1650)

TRANSLATED BY

JOHN VEITCH, LL. D.

LATE PROFESSOR OF LOGIC AND RHETORIC IN THE UNIVERSITY OF GLASGOW

From the Publisher's Preface.

The present volume contains a reprint of the preface and the first

part of the Principles of Philosophy, together with selections from

the second, third and fourth parts of that work, corresponding to

the extracts in the French edition of Gamier, are also given, as

well as an appendix containing part of Descartes' reply to the

Second Objections (viz., his formal demonstrations of the existence

of Deity). The translation is based on the original Latin edition of

the Principles, published in 1644.

The work had been translated into French during Descartes' lifetime,

and personally revised and corrected by him, the French text is

evidently deserving of the same consideration as the Latin

originals, and consequently, the additions and variations of the

French version have also been given--the additions being put in

square brackets in the text and the variations in the footnotes.

A copy of the title-page of the original edition, as given in Dr. C.

Guttler's work (Munich: C. H. Beck. 1901), are also reproduced in

the present volume.

SELECTIONS FROM THE PRINCIPLES OF PHILOSOPHY

OF DESCARTES

TRANSLATED FROM THE LATIN AND COLLATED WITH THE FRENCH

LETTER OF THE AUTHOR

TO THE FRENCH TRANSLATOR OF THE PRINCIPLES OF PHILOSOPHY SERVING FOR

A PREFACE.

Sir,--The version of my principles which you have been at pains to

make, is so elegant and finished as to lead me to expect that the

work will be more generally read in French than in Latin, and better

understood. The only apprehension I entertain is lest the title

should deter some who have not been brought up to letters, or with

whom philosophy is in bad repute, because the kind they were taught

has proved unsatisfactory; and this makes me think that it will be

useful to add a preface to it for the purpose of showing what the

MATTER of the work is, what END I had in view in writing it, and

what UTILITY may be derived from it. But although it might be my

part to write a preface of this nature, seeing I ought to know those

particulars better than any other person, I cannot nevertheless

prevail upon myself to do anything more than merely to give a

summary of the chief points that fall, as I think, to be discussed

in it: and I leave it to your discretion to present to the public

such part of them as you shall judge proper.

I should have desired, in the first place, to explain in it what

philosophy is, by commencing with the most common matters, as, for

example, that the word PHILOSOPHY signifies the study of wisdom, and

that by wisdom is to be understood not merely prudence in the

management of affairs, but a perfect knowledge of all that man can

know, as well for the conduct of his life as for the preservation of

his health and the discovery of all the arts, and that knowledge to

subserve these ends must necessarily be deduced from first causes;

so that in order to study the acquisition of it (which is properly

called philosophizing), we must commence with the investigation of

those first causes which are called PRINCIPLES. Now these principles

must possess TWO CONDITIONS: in the first place, they must be so

clear and evident that the human mind, when it attentively considers

them, cannot doubt of their truth; in the second place, the

knowledge of other things must be so dependent on them as that

though the principles themselves may indeed be known apart from what

depends on them, the latter cannot nevertheless be known apart from

the former. It will accordingly be necessary thereafter to endeavour

so to deduce from those principles the knowledge of the things that

depend on them, as that there may be nothing in the whole series of

deductions which is not perfectly manifest. God is in truth the only

being who is absolutely wise, that is, who possesses a perfect

knowledge of all things; but we may say that men are more or less

wise as their knowledge of the most important truths is greater or

less. And I am confident that there is nothing, in what I have now

said, in which all the learned do not concur.

I should, in the next place, have proposed to consider the utility

of philosophy, and at the same time have shown that, since it

embraces all that the human mind can know, we ought to believe that

it is by it we are distinguished from savages and barbarians, and

that the civilisation and culture of a nation is regulated by the

degree in which true philosophy nourishes in it, and, accordingly,

that to contain true philosophers is the highest privilege a state

can enjoy. Besides this, I should have shown that, as regards

individuals, it is not only useful for each man to have intercourse

with those who apply themselves to this study, but that it is

incomparably better he should himself direct his attention to it;

just as it is doubtless to be preferred that a man should make use

of his own eyes to direct his steps, and enjoy by means of the same

the beauties of colour and light, than that he should blindly follow

the guidance of another; though the latter course is certainly

better than to have the eyes closed with no guide except one's self.

But to live without philosophizing is in truth the same as keeping

the eyes closed without attempting to open them; and the pleasure of

seeing all that sight discloses is not to be compared with the

satisfaction afforded by the discoveries of philosophy. And,

finally, this study is more imperatively requisite for the

regulation of our manners, and for conducting us through life, than

is the use of our eyes for directing our steps. The brutes, which

have only their bodies to conserve, are continually occupied in

seeking sources of nourishment; but men, of whom the chief part is

the mind, ought to make the search after wisdom their principal

care, for wisdom is the true nourishment of the mind; and I feel

assured, moreover, that there are very many who would not fail in

the search, if they would but hope for success in it, and knew the

degree of their capabilities for it. There is no mind, how ignoble

soever it be, which remains so firmly bound up in the objects of the

senses, as not sometime or other to turn itself away from them in

the aspiration after some higher good, although not knowing

frequently wherein that good consists. The greatest favourites of

fortune--those who have health, honours, and riches in abundance--

are not more exempt from aspirations of this nature than others;

nay, I am persuaded that these are the persons who sigh the most

deeply after another good greater and more perfect still than any

they already possess. But the supreme good, considered by natural

reason without the light of faith, is nothing more than the

knowledge of truth through its first causes, in other words, the

wisdom of which philosophy is the study. And, as all these

particulars are indisputably true, all that is required to gain

assent to their truth is that they be well stated.

But as one is restrained from assenting to these doctrines by

experience, which shows that they who make pretensions to philosophy

are often less wise and reasonable than others who never applied

themselves to the study, I should have here shortly explained

wherein consists all the science we now possess, and what are the

degrees of wisdom at which we have arrived. The first degree

contains only notions so clear of themselves that they can be

acquired without meditation; the second comprehends all that the

experience of the senses dictates; the third, that which the

conversation of other men teaches us; to which may be added as the

fourth, the reading, not of all books, but especially of such as

have been written by persons capable of conveying proper

instruction, for it is a species of conversation we hold with their

authors. And it seems to me that all the wisdom we in ordinary

possess is acquired only in these four ways; for I do not class

divine revelation among them, because it does not conduct us by

degrees, but elevates us at once to an infallible faith.

There have been, indeed, in all ages great minds who endeavoured to

find a fifth road to wisdom, incomparably more sure and elevated

than the other four. The path they essayed was the search of first

causes and true principles, from which might be deduced the reasons

of all that can be known by man; and it is to them the appellation

of philosophers has been more especially accorded. I am not aware

that there is any one of them up to the present who has succeeded in

this enterprise. The first and chief whose writings we possess are

Plato and Aristotle, between whom there was no difference, except

that the former, following in the footsteps of his master, Socrates,

ingenuously confessed that he had never yet been able to find

anything certain, and that he was contented to write what seemed to

him probable, imagining, for this end, certain principles by which

he endeavoured to account for the other things. Aristotle, on the

other hand, characterised by less candour, although for twenty years

the disciple of Plato, and with no principles beyond those of his

master, completely reversed his mode of putting them, and proposed

as true and certain what it is probable he himself never esteemed as

such. But these two men had acquired much judgment and wisdom by the

four preceding means, qualities which raised their authority very

high, so much so that those who succeeded them were willing rather

to acquiesce in their opinions, than to seek better for themselves.

The chief question among their disciples, however, was as to whether

we ought to doubt of all things or hold some as certain,--a dispute

which led them on both sides into extravagant errors; for a part of

those who were for doubt, extended it even to the actions of life,

to the neglect of the most ordinary rules required for its conduct;

those, on the other hand, who maintained the doctrine of certainty,

supposing that it must depend upon the senses, trusted entirely to

them. To such an extent was this carried by Epicurus, that it is

said he ventured to affirm, contrary to all the reasonings of the

astronomers, that the sun is no larger than it appears.

It is a fault we may remark in most disputes, that, as truth is the

mean between the two opinions that are upheld, each disputant

departs from it in proportion to the degree in which he possesses

the spirit of contradiction. But the error of those who leant too

much to the side of doubt, was not followed for any length of time,

and that of the opposite party has been to some extent corrected by

the doctrine that the senses are deceitful in many instances.

Nevertheless, I do not know that this error was wholly removed by

showing that certitude is not in the senses, but in the

understanding alone when it has clear perceptions; and that while we

only possess the knowledge which is acquired in the first four

grades of wisdom, we ought not to doubt of the things that appear to

be true in what regards the conduct of life, nor esteem them as so

certain that we cannot change our opinions regarding them, even

though constrained by the evidence of reason.

From ignorance of this truth, or, if there was any one to whom it

was known, from neglect of it, the majority of those who in these

later ages aspired to be philosophers, blindly followed Aristotle,

so that they frequently corrupted the sense of his writings, and

attributed to him various opinions which he would not recognise as

his own were he now to return to the world; and those who did not

follow him, among whom are to be found many of the greatest minds,

did yet not escape being imbued with his opinions in their youth, as

these form the staple of instruction in the schools; and thus their

minds were so preoccupied that they could not rise to the knowledge

of true principles. And though I hold all the philosophers in

esteem, and am unwilling to incur odium by my censure, I can adduce

a proof of my assertion, which I do not think any of them will

gainsay, which is, that they all laid down as a principle what they

did not perfectly know. For example, I know none of them who did not

suppose that there was gravity in terrestrial bodies; but although

experience shows us very clearly that bodies we call heavy descend

towards the center of the earth, we do not, therefore, know the

nature of gravity, that is, the cause or principle in virtue of

which bodies descend, and we must derive our knowledge of it from

some other source. The same may be said of a vacuum and atoms, of

heat and cold, of dryness and humidity, and of salt, sulphur, and

mercury, and the other things of this sort which some have adopted

as their principles. But no conclusion deduced from a principle

which is not clear can be evident, even although the deduction be

formally valid; and hence it follows that no reasonings based on

such principles could lead them to the certain knowledge of any one

thing, nor consequently advance them one step in the search after

wisdom. And if they did discover any truth, this was due to one or

other of the four means above mentioned. Notwithstanding this, I am

in no degree desirous to lessen the honour which each of them can

justly claim; I am only constrained to say, for the consolation of

those who have not given their attention to study, that just as in

travelling, when we turn our back upon the place to which we were

going, we recede the farther from it in proportion as we proceed in

the new direction for a greater length of time and with greater

speed, so that, though we may be afterwards brought back to the

right way, we cannot nevertheless arrive at the destined place as

soon as if we had not moved backwards at all; so in philosophy, when

we make use of false principles, we depart the farther from the

knowledge of truth and wisdom exactly in proportion to the care with

which we cultivate them, and apply ourselves to the deduction of

diverse consequences from them, thinking that we are philosophizing

well, while we are only departing the farther from the truth; from

which it must be inferred that they who have learned the least of

all that has been hitherto distinguished by the name of philosophy

are the most fitted for the apprehension of truth.

After making those matters clear, I should, in the next place, have

desired to set forth the grounds for holding that the true

principles by which we may reach that highest degree of wisdom

wherein consists the sovereign good of human life, are those I have

proposed in this work; and two considerations alone are sufficient

to establish this--the first of which is, that these principles are

very clear, and the second, that we can deduce all other truths from

them; for it is only these two conditions that are required in true

principles. But I easily prove that they are very clear; firstly, by

a reference to the manner in which I found them, namely, by

rejecting all propositions that were in the least doubtful, for it

is certain that such as could not be rejected by this test when they

were attentively considered, are the most evident and clear which

the human mind can know. Thus by considering that he who strives to

doubt of all is unable nevertheless to doubt that he is while he

doubts, and that what reasons thus, in not being able to doubt of

itself and doubting nevertheless of everything else, is not that

which we call our body, but what we name our mind or thought, I have

taken the existence of this thought for the first principle, from

which I very clearly deduced the following truths, namely, that

there is a God who is the author of all that is in the world, and

who, being the source of all truth, cannot have created our

understanding of such a nature as to be deceived in the judgments it

forms of the things of which it possesses a very clear and distinct

perception. Those are all the principles of which I avail myself

touching immaterial or metaphysical objects, from which I most

clearly deduce these other principles of physical or corporeal

things, namely, that there are bodies extended in length, breadth,

and depth, which are of diverse figures and are moved in a variety

of ways. Such are in sum the principles from which I deduce all

other truths. The second circumstance that proves the clearness of

these principles is, that they have been known in all ages, and even

received as true and indubitable by all men, with the exception only

of the existence of God, which has been doubted by some, because

they attributed too much to the perceptions of the senses, and God

can neither be seen nor touched.

But, though all the truths which I class among my principles were

known at all times, and by all men, nevertheless, there has been no

one up to the present, who, so far as I know, has adopted them as

principles of philosophy: in other words, as such that we can deduce

from them the knowledge of whatever else is in the world. It

accordingly now remains for me to prove that they are such; and it

appears to me that I cannot better establish this than by the test

of experience: in other words, by inviting readers to peruse the

following work. For, though I have not treated in it of all matters-

-that being impossible--I think I have so explained all of which I

had occasion to treat, that they who read it attentively will have

ground for the persuasion that it is unnecessary to seek for any

other principles than those I have given, in order to arrive at the

most exalted knowledge of which the mind of man is capable;

especially if, after the perusal of my writings, they take the

trouble to consider how many diverse questions are therein discussed

and explained, and, referring to the writings of others, they see

how little probability there is in the reasons that are adduced in

explanation of the same questions by principles different from mine.

And that they may the more easily undertake this, I might have said

that those imbued with my doctrines have much less difficulty in

comprehending the writings of others, and estimating their true

value, than those who have not been so imbued; and this is precisely

the opposite of what I before said of such as commenced with the

ancient philosophy, namely, that the more they have studied it the

less fit are they for rightly apprehending the truth.

I should also have added a word of advice regarding the manner of

reading this work, which is, that I should wish the reader at first

to go over the whole of it, as he would a romance, without greatly

straining his attention, or tarrying at the difficulties he may

perhaps meet with in it, with the view simply of knowing in general

the matters of which I treat; and that afterwards, if they seem to

him to merit a more careful examination, and he feel a desire to

know their causes, he may read it a second time, in order to observe

the connection of my reasonings; but that he must not then give it

up in despair, although he may not everywhere sufficiently discover

the connection of the proof, or understand all the reasonings--it

being only necessary to mark with a pen the places where the

difficulties occur, and continue to read without interruption to the

end; then, if he does not grudge to take up the book a third time, I

am confident he will find in a fresh perusal the solution of most of

the difficulties he will have marked before; and that, if any still

remain, their solution will in the end be found in another reading.

I have observed, on examining the natural constitutions of different

minds, that there are hardly any so dull or slow of understanding as

to be incapable of apprehending good opinions, or even of acquiring

all the highest sciences, if they be but conducted along the right

road. And this can also be proved by reason; for, as the principles

are clear, and as nothing ought to be deduced from them, unless most

manifest inferences, no one is so devoid of intelligence as to be

unable to comprehend the conclusions that flow from them. But,

besides the entanglement of prejudices, from which no one is

entirely exempt, although it is they who have been the most ardent

students of the false sciences that receive the greatest detriment

from them, it happens very generally that people of ordinary

capacity neglect to study from a conviction that they want ability,

and that others, who are more ardent, press on too rapidly: whence

it comes to pass that they frequently admit principles far from

evident, and draw doubtful inferences from them. For this reason, I

should wish to assure those who are too distrustful of their own

ability that there is nothing in my writings which they may not

entirely understand, if they only take the trouble to examine them;

and I should wish, at the same time, to warn those of an opposite

tendency that even the most superior minds will have need of much

time and attention to remark all I designed to embrace therein.

After this, that I might lead men to understand the real design I

had in publishing them, I should have wished here to explain the

order which it seems to me one ought to follow with the view of

instructing himself. In the first place, a man who has merely the

vulgar and imperfect knowledge which can be acquired by the four

means above explained, ought, before all else, to endeavour to form

for himself a code of morals, sufficient to regulate the actions of

his life, as well for the reason that this does not admit of delay

as because it ought to be our first care to live well. In the next

place, he ought to study Logic, not that of the schools, for it is

only, properly speaking, a dialectic which teaches the mode of

expounding to others what we already know, or even of speaking much,

without judgment, of what we do not know, by which means it corrupts

rather than increases good sense--but the logic which teaches the

right conduct of the reason with the view of discovering the truths

of which we are ignorant; and, because it greatly depends on usage,

it is desirable he should exercise himself for a length of time in

practising its rules on easy and simple questions, as those of the

mathematics. Then, when he has acquired some skill in discovering

the truth in these questions, he should commence to apply himself in

earnest to true philosophy, of which the first part is Metaphysics,

containing the principles of knowledge, among which is the

explication of the principal attributes of God, of the immateriality

of the soul, and of all the clear and simple notions that are in us;

the second is Physics, in which, after finding the true principles

of material things, we examine, in general, how the whole universe

has been framed; in the next place, we consider, in particular, the

nature of the earth, and of all the bodies that are most generally

found upon it, as air, water, fire, the loadstone and other

minerals. In the next place it is necessary also to examine singly

the nature of plants, of animals, and above all of man, in order

that we may thereafter be able to discover the other sciences that

are useful to us. Thus, all Philosophy is like a tree, of which

Metaphysics is the root, Physics the trunk, and all the other

sciences the branches that grow out of this trunk, which are reduced

to three principal, namely, Medicine, Mechanics, and Ethics. By the

science of Morals, I understand the highest and most perfect which,

presupposing an entire knowledge of the other sciences, is the last

degree of wisdom.

But as it is not from the roots or the trunks of trees that we

gather the fruit, but only from the extremities of their branches,

so the principal utility of philosophy depends on the separate uses

of its parts, which we can only learn last of all. But, though I am

ignorant of almost all these, the zeal I have always felt in

endeavouring to be of service to the public, was the reason why I

published, some ten or twelve years ago, certain Essays on the

doctrines I thought I had acquired. The first part of these Essays

was a "Discourse on the Method of rightly conducting the Reason, and

seeking Truth in the Sciences," in which I gave a summary of the

principal rules of logic, and also of an imperfect ethic, which a

person may follow provisionally so long as he does not know any

better. The other parts were three treatises: the first of

Dioptrics, the second of Meteors, and the third of Geometry. In the

Dioptrics, I designed to show that we might proceed far enough in

philosophy as to arrive, by its means, at the knowledge of the arts

that are useful to life, because the invention of the telescope, of

which I there gave an explanation, is one of the most difficult that

has ever been made. In the treatise of Meteors, I desired to exhibit

the difference that subsists between the philosophy I cultivate and

that taught in the schools, in which the same matters are usually

discussed. In fine, in the Geometry, I professed to demonstrate that

I had discovered many things that were before unknown, and thus

afford ground for believing that we may still discover many others,

with the view of thus stimulating all to the investigation of truth.

Since that period, anticipating the difficulty which many would

experience in apprehending the foundations of the Metaphysics, I

endeavoured to explain the chief points of them in a book of

Meditations, which is not in itself large, but the size of which has

been increased, and the matter greatly illustrated, by the

Objections which several very learned persons sent to me on occasion

of it, and by the Replies which I made to them. At length, after it

appeared to me that those preceding treatises had sufficiently

prepared the minds of my readers for the Principles of Philosophy, I

also published it; and I have divided this work into four parts, the

first of which contains the principles of human knowledge, and which

may be called the First Philosophy, or Metaphysics. That this part,

accordingly, may be properly understood, it will be necessary to

read beforehand the book of Meditations I wrote on the same subject.

The other three parts contain all that is most general in Physics,

namely, the explication of the first laws or principles of nature,

and the way in which the heavens, the fixed stars, the planets,

comets, and generally the whole universe, were composed; in the next

place, the explication, in particular, of the nature of this earth,

the air, water, fire, the magnet, which are the bodies we most

commonly find everywhere around it, and of all the qualities we

observe in these bodies, as light, heat, gravity, and the like. In

this way, it seems to me, I have commenced the orderly explanation

of the whole of philosophy, without omitting any of the matters that

ought to precede the last which I discussed. But to bring this

undertaking to its conclusion, I ought hereafter to explain, in the

same manner, the nature of the other more particular bodies that are

on the earth, namely, minerals, plants, animals, and especially man;

finally, to treat thereafter with accuracy of Medicine, Ethics, and

Mechanics. I should require to do this in order to give to the world

a complete body of philosophy; and I do not yet feel myself so old,-

-I do not so much distrust my strength, nor do I find myself so far

removed from the knowledge of what remains, as that I should not

dare to undertake to complete this design, provided I were in a

position to make all the experiments which I should require for the

basis and verification of my reasonings. But seeing that would

demand a great expenditure, to which the resources of a private

individual like myself would not be adequate, unless aided by the

public, and as I have no ground to expect this aid, I believe that I

ought for the future to content myself with studying for my own

instruction, and posterity will excuse me if I fail hereafter to

labour for them.

Meanwhile, that it may be seen wherein I think I have already

promoted the general good, I will here mention the fruits that may

be gathered from my Principles. The first is the satisfaction which

the mind will experience on finding in the work many truths before

unknown; for although frequently truth does not so greatly affect

our imagination as falsity and fiction, because it seems less

wonderful and is more simple, yet the gratification it affords is

always more durable and solid. The second fruit is, that in studying

these principles we will become accustomed by degrees to judge

better of all the things we come in contact with, and thus be made

wiser, in which respect the effect will be quite the opposite of the

common philosophy, for we may easily remark in those we call pedants

that it renders them less capable of rightly exercising their reason

than they would have been if they had never known it. The third is,

that the truths which they contain, being highly clear and certain,

will take away all ground of dispute, and thus dispose men's minds

to gentleness and concord; whereas the contrary is the effect of the

controversies of the schools, which, as they insensibly render those

who are exercised in them more wrangling and opinionative, are

perhaps the prime cause of the heresies and dissensions that now

harass the world. The last and chief fruit of these Principles is,

that one will be able, by cultivating them, to discover many truths

I myself have not unfolded, and thus passing by degrees from one to

another, to acquire in course of time a perfect knowledge of the

whole of philosophy, and to rise to the highest degree of wisdom.

For just as all the arts, though in their beginnings they are rude

and imperfect, are yet gradually perfected by practice, from their

containing at first something true, and whose effect experience

evinces; so in philosophy, when we have true principles, we cannot

fail by following them to meet sometimes with other truths; and we

could not better prove the falsity of those of Aristotle, than by

saying that men made no progress in knowledge by their means during

the many ages they prosecuted them.

I well know that there are some men so precipitate and accustomed to

use so little circumspection in what they do, that, even with the

most solid foundations, they could not rear a firm superstructure;

and as it is usually those who are the readiest to make books, they

would in a short time mar all that I have done, and introduce

uncertainty and doubt into my manner of philosophizing, from which I

have carefully endeavoured to banish them, if people were to receive

their writings as mine, or as representing my opinions. I had, not

long ago, some experience of this in one of those who were believed

desirous of following me the most closely, [Footnote: Regius; see La

Vie de M. Descartes, reduite en abrege (Baillet). Liv. vii., chap.

vii.--T.] and one too of whom I had somewhere said that I had such

confidence in his genius as to believe that he adhered to no

opinions which I should not be ready to avow as mine; for he last

year published a book entitled "Fundamental Physics," in which,

although he seems to have written nothing on the subject of Physics

and Medicine which he did not take from my writings, as well from

those I have published as from another still imperfect on the nature

of animals, which fell into his hands; nevertheless, because he has

copied them badly, and changed the order, and denied certain

metaphysical truths upon which all Physics ought to be based, I am

obliged wholly to disavow his work, and here to request readers not

to attribute to me any opinion unless they find it expressly stated

in my own writings, and to receive no opinion as true, whether in my

writings or elsewhere, unless they see that it is very clearly

deduced from true principles. I well know, likewise, that many ages

may elapse ere all the truths deducible from these principles are

evolved out of them, as well because the greater number of such as

remain to be discovered depend on certain particular experiments

that never occur by chance, but which require to be investigated

with care and expense by men of the highest intelligence, as because

it will hardly happen that the same persons who have the sagacity to

make a right use of them, will possess also the means of making

them, and also because the majority of the best minds have formed so

low an estimate of philosophy in general, from the imperfections

they have remarked in the kind in vogue up to the present time, that

they cannot apply themselves to the search after truth.

But, in conclusion, if the difference discernible between the

principles in question and those of every other system, and the

great array of truths deducible from them, lead them to discern the

importance of continuing the search after these truths, and to

observe the degree of wisdom, the perfection and felicity of life,

to which they are fitted to conduct us, I venture to believe that

there will not be found one who is not ready to labour hard in so

profitable a study, or at least to favour and aid with all his might

those who shall devote themselves to it with success.

The height of my wishes is, that posterity may sometime behold the

happy issue of it, etc.

TO THE MOST SERENE PRINCESS,

ELIZABETH, ELDEST DAUGHTER OF FREDERICK, KING OF BOHEMIA, COUNT

PALATINE, AND ELECTOR OF THE SACRED ROMAN EMPIRE.

MADAM,--The greatest advantage I have derived from the writings

which I have already published, has arisen from my having, through

means of them, become known to your Highness, and thus been

privileged to hold occasional converse with one in whom so many rare

and estimable qualities are united, as to lead me to believe I

should do service to the public by proposing them as an example to

posterity. It would ill become me to flatter, or to give expression

to anything of which I had no certain knowledge, especially in the

first pages of a work in which I aim at laying down the principles

of truth. And the generous modesty that is conspicuous in all your

actions, assures me that the frank and simple judgment of a man who

only writes what he believes will be more agreeable to you than the

ornate laudations of those who have studied the art of compliment.

For this reason, I will give insertion to nothing in this letter for

which I have not the certainty both of experience and reason; and in

the exordium, as in the rest of the work, I will write only as

becomes a philosopher. There is a vast difference between real and

apparent virtues; and there is also a great discrepancy between

those real virtues that proceed from an accurate knowledge of the

truth, and such as are accompanied with ignorance or error. The

virtues I call apparent are only, properly speaking, vices, which,

as they are less frequent than the vices that are opposed to them,

and are farther removed from them than the intermediate virtues, are

usually held in higher esteem than those virtues. Thus, because

those who fear dangers too much are more numerous than they who fear

them too little, temerity is frequently opposed to the vice of

timidity, and taken for a virtue, and is commonly more highly

esteemed than true fortitude. Thus, also, the prodigal are in

ordinary more praised than the liberal; and none more easily acquire

a great reputation for piety than the superstitious and

hypocritical. With regard to true virtues, these do not all proceed

from true knowledge, for there are some that likewise spring from

defect or error; thus, simplicity is frequently the source of

goodness, fear of devotion, and despair of courage. The virtues that

are thus accompanied with some imperfections differ from each other,

and have received diverse appellations. But those pure and perfect

virtues that arise from the knowledge of good alone are all of the

same nature, and may be comprised under the single term wisdom. For,

whoever owns the firm and constant resolution of always using his

reason as well as lies in his power, and in all his actions of doing

what he judges to be best, is truly wise, as far as his nature

permits; and by this alone he is just, courageous, temperate, and

possesses all the other virtues, but so well balanced as that none

of them appears more prominent than another: and for this reason,

although they are much more perfect than the virtues that blaze

forth through the mixture of some defect, yet, because the crowd

thus observes them less, they are not usually extolled so highly.

Besides, of the two things that are requisite for the wisdom thus

described, namely, the perception of the understanding and the

disposition of the will, it is only that which lies in the will

which all men can possess equally, inasmuch as the understanding of

some is inferior to that of others. But although those who have only

an inferior understanding may be as perfectly wise as their nature

permits, and may render themselves highly acceptable to God by their

virtue, provided they preserve always a firm and constant resolution

to do all that they shall judge to be right, and to omit nothing

that may lead them to the knowledge of the duties of which they are

ignorant; nevertheless, those who preserve a constant resolution of

performing the right, and are especially careful in instructing

themselves, and who possess also a highly perspicacious intellect,

arrive doubtless at a higher degree of wisdom than others; and I see

that these three particulars are found in great perfection in your

Highness. For, in the first place, your desire of self-instruction

is manifest, from the circumstance that neither the amusements of

the court, nor the accustomed mode of educating ladies, which

ordinarily condemns them to ignorance, have been sufficient to

prevent you from studying with much care all that is best in the

arts and sciences; and the incomparable perspicacity of your

intellect is evinced by this, that you penetrated the secrets of the

sciences and acquired an accurate knowledge of them in a very short

period. But of the vigour of your intellect I have a still stronger

proof, and one peculiar to myself, in that I have never yet met any

one who understood so generally and so well as yourself all that is

contained in my writings. For there are several, even among men of

the highest intellect and learning, who find them very obscure. And

I remark, in almost all those who are versant in Metaphysics, that

they are wholly disinclined from Geometry; and, on the other hand,

that the cultivators of Geometry have no ability for the

investigations of the First Philosophy: insomuch that I can say with

truth I know but one mind, and that is your own, to which both

studies are alike congenial, and which I therefore, with propriety,

designate incomparable. But what most of all enhances my admiration

is, that so accurate and varied an acquaintance with the whole

circle of the sciences is not found in some aged doctor who has

employed many years in contemplation, but in a Princess still young,

and whose countenance and years would more fitly represent one of

the Graces than a Muse or the sage Minerva. In conclusion, I not

only remark in your Highness all that is requisite on the part of

the mind to perfect and sublime wisdom, but also all that can be

required on the part of the will or the manners, in which benignity

and gentleness are so conjoined with majesty that, though fortune

has attacked you with continued injustice, it has failed either to

irritate or crush you. And this constrains me to such veneration

that I not only think this work due to you, since it treats of

philosophy which is the study of wisdom, but likewise feel not more

zeal for my reputation as a philosopher than pleasure in subscribing

myself,--

Of your most Serene Highness, The most devoted servant,

DESCARTES.

PART I.

OF THE PRINCIPLES OF HUMAN KNOWLEDGE.

I. THAT in order to seek truth, it is necessary once in the course

of our life, to doubt, as far as possible, of all things.

As we were at one time children, and as we formed various judgments

regarding the objects presented to our senses, when as yet we had

not the entire use of our reason, numerous prejudices stand in the

way of our arriving at the knowledge of truth; and of these it seems

impossible for us to rid ourselves, unless we undertake, once in our

lifetime, to doubt of all those things in which we may discover even

the smallest suspicion of uncertainty.

II. That we ought also to consider as false all that is doubtful.

Moreover, it will be useful likewise to esteem as false the things

of which we shall be able to doubt, that we may with greater

clearness discover what possesses most certainty and is the easiest

to know.

III. That we ought not meanwhile to make use of doubt in the

conduct of life.

In the meantime, it is to be observed that we are to avail ourselves

of this general doubt only while engaged in the contemplation of

truth. For, as far as concerns the conduct of life, we are very

frequently obliged to follow opinions merely probable, or even

sometimes, though of two courses of action we may not perceive more

probability in the one than in the other, to choose one or other,

seeing the opportunity of acting would not unfrequently pass away

before we could free ourselves from our doubts.

IV. Why we may doubt of sensible things.

Accordingly, since we now only design to apply ourselves to the

investigation of truth, we will doubt, first, whether of all the

things that have ever fallen under our senses, or which we have ever

imagined, any one really exist; in the first place, because we know

by experience that the senses sometimes err, and it would be

imprudent to trust too much to what has even once deceived us;

secondly, because in dreams we perpetually seem to perceive or

imagine innumerable objects which have no existence. And to one who

has thus resolved upon a general doubt, there appear no marks by

which he can with certainty distinguish sleep from the waking state.

V. Why we may also doubt of mathematical demonstrations.

We will also doubt of the other things we have before held as most

certain, even of the demonstrations of mathematics, and of their

principles which we have hitherto deemed self-evident; in the first

place, because we have sometimes seen men fall into error in such

matters, and admit as absolutely certain and self evident what to us

appeared false, but chiefly because we have learnt that God who

created us is all-powerful; for we do not yet know whether perhaps

it was his will to create us so that we are always deceived, even in

the things we think we know best: since this does not appear more

impossible than our being occasionally deceived, which, however, as

observation teaches us, is the case. And if we suppose that an all-

powerful God is not the author of our being, and that we exist of

ourselves or by some other means, still, the less powerful we

suppose our author to be, the greater reason will we have for

believing that we are not so perfect as that we may not be

continually deceived.

VI. That we possess a free-will, by which we can withhold our

assent from what is doubtful, and thus avoid error.

But meanwhile, whoever in the end may be the author of our being,

and however powerful and deceitful he may be, we are nevertheless

conscious of a freedom, by which we can refrain from admitting to a

place in our belief aught that is not manifestly certain and

undoubted, and thus guard against ever being deceived.

VII. That we cannot doubt of our existence while we doubt, and that

this is the first knowledge we acquire when we philosophize in

order.

While we thus reject all of which we can entertain the smallest

doubt, and even imagine that it is false, we easily indeed suppose

that there is neither God, nor sky, nor bodies, and that we

ourselves even have neither hands nor feet, nor, finally, a body;

but we cannot in the same way suppose that we are not while we doubt

of the truth of these things; for there is a repugnance in

conceiving that what thinks does not exist at the very time when it

thinks. Accordingly, the knowledge, _I_ THINK, THEREFORE _I_ AM, is

the first and most certain that occurs to one who philosophizes

orderly.

VIII. That we hence discover the distinction between the mind and

the body, or between a thinking and corporeal thing.

And this is the best mode of discovering the nature of the mind, and

its distinctness from the body: for examining what we are, while

supposing, as we now do, that there is nothing really existing apart

from our thought, we clearly perceive that neither extension, nor

figure, nor local motion,[Footnote: Instead of "local motion," the

French has "existence in any place."] nor anything similar that can

be attributed to body, pertains to our nature, and nothing save

thought alone; and, consequently, that the notion we have of our

mind precedes that of any corporeal thing, and is more certain,

seeing we still doubt whether there is any body in existence, while

we already perceive that we think.

IX. What thought (COGITATIO) is.

By the word thought, I understand all that which so takes place in

us that we of ourselves are immediately conscious of it; and,

accordingly, not only to understand (INTELLIGERE, ENTENDRE), to will

(VELLE), to imagine (IMAGINARI), but even to perceive (SENTIRE,

SENTIR), are here the same as to think (COGITARE, PENSER). For if I

say, I see, or, I walk, therefore I am; and if I understand by

vision or walking the act of my eyes or of my limbs, which is the

work of the body, the conclusion is not absolutely certain, because,

as is often the case in dreams, I may think that I see or walk,

although I do not open my eyes or move from my place, and even,

perhaps, although I have no body: but, if I mean the sensation

itself, or consciousness of seeing or walking, the knowledge is

manifestly certain, because it is then referred to the mind, which

alone perceives or is conscious that it sees or walks. [Footnote: In

the French, "which alone has the power of perceiving, or of being

conscious in any other way whatever."]

X. That the notions which are simplest and self-evident, are

obscured by logical definitions; and that such are not to be

reckoned among the cognitions acquired by study, [but as born with

us].

I do not here explain several other terms which I have used, or

design to use in the sequel, because their meaning seems to me

sufficiently self-evident. And I frequently remarked that

philosophers erred in attempting to explain, by logical definitions,

such truths as are most simple and self-evident; for they thus only

rendered them more obscure. And when I said that the proposition,

_I_ THINK, THEREFORE _I_ AM, is of all others the first and most

certain which occurs to one philosophizing orderly, I did not

therefore deny that it was necessary to know what thought,

existence, and certitude are, and the truth that, in order to think

it is necessary to be, and the like; but, because these are the most

simple notions, and such as of themselves afford the knowledge of

nothing existing, I did not judge it proper there to enumerate them.

XI. How we can know our mind more clearly than our body.

But now that it may be discerned how the knowledge we have of the

mind not only precedes, and has greater certainty, but is even

clearer, than that we have of the body, it must be remarked, as a

matter that is highly manifest by the natural light, that to nothing

no affections or qualities belong; and, accordingly, that where we

observe certain affections, there a thing or substance to which

these pertain, is necessarily found. The same light also shows us

that we know a thing or substance more clearly in proportion as we

discover in it a greater number of qualities. Now, it is manifest

that we remark a greater number of qualities in our mind than in any

other thing; for there is no occasion on which we know anything

whatever when we are not at the same time led with much greater

certainty to the knowledge of our own mind. For example, if I judge

that there is an earth because I touch or see it, on the same

ground, and with still greater reason, I must be persuaded that my

mind exists; for it may be, perhaps, that I think I touch the earth

while there is one in existence; but it is not possible that I

should so judge, and my mind which thus judges not exist; and the

same holds good of whatever object is presented to our mind.

XII. How it happens that every one does not come equally to know

this.

Those who have not philosophized in order have had other opinions on

this subject, because they never distinguished with sufficient care

the mind from the body. For, although they had no difficulty in

believing that they themselves existed, and that they had a higher

assurance of this than of any other thing, nevertheless, as they did

not observe that by THEMSELVES, they ought here to understand their

MINDS alone [when the question related to metaphysical certainty];

and since, on the contrary, they rather meant their bodies which

they saw with their eyes, touched with their hands, and to which

they erroneously attributed the faculty of perception, they were

prevented from distinctly apprehending the nature of the mind.

XIII. In what sense the knowledge of other things depends upon the

knowledge of God.

But when the mind, which thus knows itself but is still in doubt as

to all other things, looks around on all sides, with a view to the

farther extension of its knowledge, it first of all discovers within

itself the ideas of many things; and while it simply contemplates

them, and neither affirms nor denies that there is anything beyond

itself corresponding to them, it is in no danger of erring. The mind

also discovers certain common notions out of which it frames various

demonstrations that carry conviction to such a degree as to render

doubt of their truth impossible, so long as we give attention to

them. For example, the mind has within itself ideas of numbers and

figures, and it has likewise among its common notions the principle

THAT IF EQUALS BE ADDED TO EQUALS THE WHOLES WILL BE EQUAL and the

like; from which it is easy to demonstrate that the three angles of

a triangle are equal to two right angles, etc. Now, so long as we

attend to the premises from which this conclusion and others similar

to it were deduced, we feel assured of their truth; but, as the mind

cannot always think of these with attention, when it has the

remembrance of a conclusion without recollecting the order of its

deduction, and is uncertain whether the author of its being has

created it of a nature that is liable to be deceived, even in what

appears most evident, it perceives that there is just ground to

distrust the truth of such conclusions, and that it cannot possess

any certain knowledge until it has discovered its author.

XIV. That we may validly infer the existence of God from necessary

existence being comprised in the concept we have of him.

When the mind afterwards reviews the different ideas that are in it,

it discovers what is by far the chief among them--that of a Being

omniscient, all-powerful, and absolutely perfect; and it observes

that in this idea there is contained not only possible and

contingent existence, as in the ideas of all other things which it

clearly perceives, but existence absolutely necessary and eternal.

And just as because, for example, the equality of its three angles

to two right angles is necessarily comprised in the idea of a

triangle, the mind is firmly persuaded that the three angles of a

triangle are equal to two right angles; so, from its perceiving

necessary and eternal existence to be comprised in the idea which it

has of an all-perfect Being, it ought manifestly to conclude that

this all-perfect Being exists.

XV. That necessary existence is not in the same way comprised in

the notions which we have of other things, but merely contingent

existence.

The mind will be still more certain of the truth of this conclusion,

if it consider that it has no idea of any other thing in which it

can discover that necessary existence is contained; for, from this

circumstance alone, it will discern that the idea of an all-perfect

Being has not been framed by itself, and that it does not represent

a chimera, but a true and immutable nature, which must exist since

it can only be conceived as necessarily existing.

XVI. That prejudices hinder many from clearly knowing the necessity

of the existence of God.

Our mind would have no difficulty in assenting to this truth, if it

were, first of all, wholly free from prejudices; but as we have been

accustomed to distinguish, in all other things, essence from

existence, and to imagine at will many ideas of things which neither

are nor have been, it easily happens, when we do not steadily fix

our thoughts on the contemplation of the all-perfect Being, that a

doubt arises as to whether the idea we have of him is not one of

those which we frame at pleasure, or at least of that class to whose

essence existence does not pertain.

XVII. That the greater objective (representative) perfection there

is in our idea of a thing, the greater also must be the perfection

of its cause.

When we further reflect on the various ideas that are in us, it is

easy to perceive that there is not much difference among them, when

we consider them simply as certain modes of thinking, but that they

are widely different, considered in reference to the objects they

represent; and that their causes must be so much the more perfect

according to the degree of objective perfection contained in them.

[Footnote: "as what they represent of their object has more

perfection."--FRENCH.] For there is no difference between this and

the case of a person who has the idea of a machine, in the

construction of which great skill is displayed, in which

circumstances we have a right to inquire how he came by this idea,

whether, for example, he somewhere saw such a machine constructed by

another, or whether he was so accurately taught the mechanical

sciences, or is endowed with such force of genius, that he was able

of himself to invent it, without having elsewhere seen anything like

it; for all the ingenuity which is contained in the idea objectively

only, or as it were in a picture, must exist at least in its first

and chief cause, whatever that may be, not only objectively or

representatively, but in truth formally or eminently.

XVIII. That the existence of God may be again inferred from the

above.

Thus, because we discover in our minds the idea of God, or of an

all-perfect Being, we have a right to inquire into the source whence

we derive it; and we will discover that the perfections it

represents are so immense as to render it quite certain that we

could only derive it from an all-perfect Being; that is, from a God

really existing. For it is not only manifest by the natural light

that nothing cannot be the cause of anything whatever, and that the

more perfect cannot arise from the less perfect, so as to be thereby

produced as by its efficient and total cause, but also that it is

impossible we can have the idea or representation of anything

whatever, unless there be somewhere, either in us or out of us, an

original which comprises, in reality, all the perfections that are

thus represented to us; but, as we do not in any way find in

ourselves those absolute perfections of which we have the idea, we

must conclude that they exist in some nature different from ours,

that is, in God, or at least that they were once in him; and it most

manifestly follows [from their infinity] that they are still there.

XIX. That, although we may not comprehend the nature of God, there

is yet nothing which we know so clearly as his perfections.

This will appear sufficiently certain and manifest to those who have

been accustomed to contemplate the idea of God, and to turn their

thoughts to his infinite perfections; for, although we may not

comprehend them, because it is of the nature of the infinite not to

be comprehended by what is finite, we nevertheless conceive them

more clearly and distinctly than material objects, for this reason,

that, being simple, and unobscured by limits,[Footnote: After

LIMITS, "what of them we do conceive is much less confused. There

is, besides, no speculation more calculated to aid in perfecting our

understanding, and which is more important than this, inasmuch as

the consideration of an object that has no limits to its perfections

fills us with satisfaction and assurance."-FRENCH.] they occupy our

mind more fully.

XX. That we are not the cause of ourselves, but that this is God,

and consequently that there is a God.

But, because every one has not observed this, and because, when we

have an idea of any machine in which great skill is displayed, we

usually know with sufficient accuracy the manner in which we

obtained it, and as we cannot even recollect when the idea we have

of a God was communicated to us by him, seeing it was always in our

minds, it is still necessary that we should continue our review, and

make inquiry after our author, possessing, as we do, the idea of the

infinite perfections of a God: for it is in the highest degree

evident by the natural light, that that which knows something more

perfect than itself, is not the source of its own being, since it

would thus have given to itself all the perfections which it knows;

and that, consequently, it could draw its origin from no other being

than from him who possesses in himself all those perfections, that

is, from God.

XXI. That the duration alone of our life is sufficient to

demonstrate the existence of God.

The truth of this demonstration will clearly appear, provided we

consider the nature of time, or the duration of things; for this is

of such a kind that its parts are not mutually dependent, and never

co-existent; and, accordingly, from the fact that we now are, it

does not necessarily follow that we shall be a moment afterwards,

unless some cause, viz., that which first produced us, shall, as it

were, continually reproduce us, that is, conserve us. For we easily

understand that there is no power in us by which we can conserve

ourselves, and that the being who has so much power as to conserve

us out of himself, must also by so much the greater reason conserve

himself, or rather stand in need of being conserved by no one

whatever, and, in fine, be God.

XXII. That in knowing the existence of God, in the manner here

explained, we likewise know all his attributes, as far as they can

be known by the natural light alone.

There is the great advantage in proving the existence of God in this

way, viz., by his idea, that we at the same time know what he is, as

far as the weakness of our nature allows; for, reflecting on the

idea we have of him which is born with us, we perceive that he is

eternal, omniscient, omnipotent, the source of all goodness and

truth, creator of all things, and that, in fine, he has in himself

all that in which we can clearly discover any infinite perfection or

good that is not limited by any imperfection.

XXIII. That God is not corporeal, and does not perceive by means of

senses as we do, or will the evil of sin.

For there are indeed many things in the world that are to a certain

extent imperfect or limited, though possessing also some perfection;

and it is accordingly impossible that any such can be in God. Thus,

looking to corporeal nature,[Footnote: In the French, "since

extension constitutes the nature of body."] since divisibility is

included in local extension, and this indicates imperfection, it is

certain that God is not body. And although in men it is to some

degree a perfection to be capable of perceiving by means of the

senses, nevertheless since in every sense there is passivity

[Footnote: In the French, "because our perceptions arise from

impressions made upon us from another source," i.e., than

ourselves.] which indicates dependency, we must conclude that God is

in no manner possessed of senses, and that he only understands and

wills, not, however, like us, by acts in any way distinct, but

always by an act that is one, identical, and the simplest possible,

understands, wills, and operates all, that is, all things that in

reality exist; for he does not will the evil of sin, seeing this is

but the negation of being.

XXIV. That in passing from the knowledge of God to the knowledge of

the creatures, it is necessary to remember that our understanding is

finite, and the power of God infinite.

But as we know that God alone is the true cause of all that is or

can be, we will doubtless follow the best way of philosophizing, if,

from the knowledge we have of God himself, we pass to the

explication of the things which he has created, and essay to deduce

it from the notions that are naturally in our minds, for we will

thus obtain the most perfect science, that is, the knowledge of

effects through their causes. But that we may be able to make this

attempt with sufficient security from error, we must use the

precaution to bear in mind as much as possible that God, who is the

author of things, is infinite, while we are wholly finite.

XXV. That we must believe all that God has revealed, although it

may surpass the reach of our faculties.

Thus, if perhaps God reveal to us or others, matters concerning

himself which surpass the natural powers of our mind, such as the

mysteries of the incarnation and of the trinity, we will not refuse

to believe them, although we may not clearly understand them; nor

will we be in any way surprised to find in the immensity of his

nature, or even in what he has created, many things that exceed our

comprehension.

XXVI. That it is not needful to enter into disputes [Footnote: "to

essay to comprehend the infinite."--FRENCH.] regarding the infinite,

but merely to hold all that in which we can find no limits as

indefinite, such as the extension of the world, the divisibility of

the parts of matter, the number of the stars, etc.

We will thus never embarrass ourselves by disputes about the

infinite, seeing it would be absurd for us who are finite to

undertake to determine anything regarding it, and thus as it were to

limit it by endeavouring to comprehend it. We will accordingly give

ourselves no concern to reply to those who demand whether the half

of an infinite line is also infinite, and whether an infinite number

is even or odd, and the like, because it is only such as imagine

their minds to be infinite who seem bound to entertain questions of

this sort. And, for our part, looking to all those things in which

in certain senses, we discover no limits, we will not, therefore,

affirm that they are infinite, but will regard them simply as

indefinite. Thus, because we cannot imagine extension so great that

we cannot still conceive greater, we will say that the magnitude of

possible things is indefinite, and because a body cannot be divided

into parts so small that each of these may not be conceived as again

divided into others still smaller, let us regard quantity as

divisible into parts whose number is indefinite; and as we cannot

imagine so many stars that it would seem impossible for God to

create more, let us suppose that their number is indefinite, and so

in other instances.

XXVII. What difference there is between the indefinite and the

infinite.

And we will call those things indefinite rather than infinite, with

the view of reserving to God alone the appellation of infinite; in

the first place, because not only do we discover in him alone no

limits on any side, but also because we positively conceive that he

admits of none; and in the second place, because we do not in the

same way positively conceive that other things are in every part

unlimited, but merely negatively admit that their limits, if they

have any, cannot be discovered by us.

XXVIII. That we must examine, not the final, but the efficient,

causes of created things.

Likewise, finally, we will not seek reasons of natural things from

the end which God or nature proposed to himself in their creation

(i. e., final causes), [Footnote: "We will not stop to consider the

ends which God proposed to himself in the creation of the world, and

we will entirely reject from our philosophy the search of final

causes!"--French.] for we ought not to presume so far as to think

that we are sharers in the counsels of Deity, but, considering him

as the efficient cause of all things, let us endeavour to discover

by the natural light [Footnote: "Faculty of reasoning."--FRENCH.]

which he has planted in us, applied to those of his attributes of

which he has been willing we should have some knowledge, what must

be concluded regarding those effects we perceive by our senses;

bearing in mind, however, what has been already said, that we must

only confide in this natural light so long as nothing contrary to

its dictates is revealed by God himself. [Footnote: The last clause,

beginning "bearing in mind." is omitted in the French.]

XXIX. That God is not the cause of our errors.

The first attribute of God which here falls to be considered, is

that he is absolutely veracious and the source of all light, so that

it is plainly repugnant for him to deceive us, or to be properly and

positively the cause of the errors to which we are consciously

subject; for although the address to deceive seems to be some mark

of subtlety of mind among men, yet without doubt the will to deceive

only proceeds from malice or from fear and weakness, and

consequently cannot be attributed to God.

XXX. That consequently all which we clearly perceive is true, and

that we are thus delivered from the doubts above proposed.

Whence it follows, that the light of nature, or faculty of knowledge

given us by God, can never compass any object which is not true, in

as far as it attains to a knowledge of it, that is, in as far as the

object is clearly and distinctly apprehended. For God would have

merited the appellation of a deceiver if he had given us this

faculty perverted, and such as might lead us to take falsity for

truth [when we used it aright]. Thus the highest doubt is removed,

which arose from our ignorance on the point as to whether perhaps

our nature was such that we might be deceived even in those things

that appear to us the most evident. The same principle ought also to

be of avail against all the other grounds of doubting that have been

already enumerated. For mathematical truths ought now to be above

suspicion, since these are of the clearest. And if we perceive

anything by our senses, whether while awake or asleep, we will

easily discover the truth provided we separate what there is of

clear and distinct in the knowledge from what is obscure and

confused. There is no need that I should here say more on this

subject, since it has already received ample treatment in the

metaphysical Meditations; and what follows will serve to explain it

still more accurately.

XXXI. That our errors are, in respect of God, merely negations,

but, in respect of ourselves, privations.

But as it happens that we frequently fall into error, although God

is no deceiver, if we desire to inquire into the origin and cause of

our errors, with a view to guard against them, it is necessary to

observe that they depend less on our understanding than on our will,

and that they have no need of the actual concourse of God, in order

to their production; so that, when considered in reference to God,

they are merely negations, but in reference to ourselves,

privations.

XXXII. That there are only two modes of thinking in us, viz., the

perception of the understanding and the action of the will.

For all the modes of thinking of which we are conscious may be

referred to two general classes, the one of which is the perception

or operation of the understanding, and the other the volition or

operation of the will. Thus, to perceive by the senses (SENTIRE), to

imagine, and to conceive things purely intelligible, are only

different modes of perceiving (PERCIP IENDI); but to desire, to be

averse from, to affirm, to deny, to doubt, are different modes of

willing.

XXXIII. That we never err unless when we judge of something which

we do not sufficiently apprehend.

When we apprehend anything we are in no danger of error, if we

refrain from judging of it in any way; and even when we have formed

a judgment regarding it, we would never fall into error, provided we

gave our assent only to what we clearly and distinctly perceived;

but the reason why we are usually deceived, is that we judge without

possessing an exact knowledge of that of which we judge.

XXXIV. That the will as well as the understanding is required for

judging.

I admit that the understanding is necessary for judging, there being

no room to suppose that we can judge of that which we in no way

apprehend; but the will also is required in order to our assenting

to what we have in any degree perceived. It is not necessary,

however, at least to form any judgment whatever, that we have an

entire and perfect apprehension of a thing; for we may assent to

many things of which we have only a very obscure and confused

knowledge.

XXXV. That the will is of greater extension than the understanding,

and is thus the source of our errors.

Further, the perception of the intellect extends only to the few

things that are presented to it, and is always very limited: the

will, on the other hand, may, in a certain sense, be said to be

infinite, because we observe nothing that can be the object of the

will of any other, even of the unlimited will of God, to which ours

cannot also extend, so that we easily carry it beyond the objects we

clearly perceive; and when we do this, it is not wonderful that we

happen to be deceived.

XXXVI. That our errors cannot be imputed to God.

But although God has not given us an omniscient understanding, he is

not on this account to be considered in any wise the author of our

errors, for it is of the nature of created intellect to be finite,

and of finite intellect not to embrace all things.

XXXVII. That the chief perfection of man is his being able to act

freely or by will, and that it is this which renders him worthy of

praise or blame.

That the will should be the more extensive is in harmony with its

nature: and it is a high perfection in man to be able to act by

means of it, that is, freely; and thus in a peculiar way to be the

master of his own actions, and merit praise or blame. For self-

acting machines are not commended because they perform with

exactness all the movements for which they were adapted, seeing

their motions are carried on necessarily; but the maker of them is

praised on account of the exactness with which they were framed,

because he did not act of necessity, but freely; and, on the same

principle, we must attribute to ourselves something more on this

account, that when we embrace truth, we do so not of necessity, but

freely.

XXXVIII. That error is a defect in our mode of acting, not in our

nature; and that the faults of their subjects may be frequently

attributed to other masters, but never to God.

It is true, that as often as we err, there is some defect in our

mode of action or in the use of our liberty, but not in our nature,

because this is always the same, whether our judgments be true or

false. And although God could have given to us such perspicacity of

intellect that we should never have erred, we have, notwithstanding,

no right to demand this of him; for, although with us he who was

able to prevent evil and did not is held guilty of it, God is not in

the same way to be reckoned responsible for our errors because he

had the power to prevent them, inasmuch as the dominion which some

men possess over others has been instituted for the purpose of

enabling them to hinder those under them from doing evil, whereas

the dominion which God exercises over the universe is perfectly

absolute and free. For this reason we ought to thank him for the

goods he has given us, and not complain that he has not blessed us

with all which we know it was in his power to impart.

XXXIX. That the liberty of our will is self-evident.

Finally, it is so manifest that we possess a free will, capable of

giving or withholding its assent, that this truth must be reckoned

among the first and most common notions which are born with us.

This, indeed, has already very clearly appeared, for when essaying

to doubt of all things, we went so far as to suppose even that he

who created us employed his limitless power in deceiving us in every

way, we were conscious nevertheless of being free to abstain from

believing what was not in every respect certain and undoubted. But

that of which we are unable to doubt at such a time is as self-

evident and clear as any thing we can ever know.

XL. That it is likewise certain that God has fore-ordained all

things.

But because what we have already discovered of God, gives us the

assurance that his power is so immense that we would sin in thinking

ourselves capable of ever doing anything which he had not ordained

beforehand, we should soon be embarrassed in great difficulties if

we undertook to harmonise the pre-ordination of God with the freedom

of our will, and endeavoured to comprehend both truths at once.

XLI. How the freedom of our will may be reconciled with the Divine

pre-ordination.

But, in place of this, we will be free from these embarrassments if

we recollect that our mind is limited, while the power of God, by

which he not only knew from all eternity what is or can be, but also

willed and pre-ordained it, is infinite. It thus happens that we

possess sufficient intelligence to know clearly and distinctly that

this power is in God, but not enough to comprehend how he leaves the

free actions of men indeterminate} and, on the other hand, we have

such consciousness of the liberty and indifference which exists in

ourselves, that there is nothing we more clearly or perfectly

comprehend: [so that the omnipotence of God ought not to keep us

from believing it]. For it would be absurd to doubt of that of which

we are fully conscious, and which we experience as existing in

ourselves, because we do not comprehend another matter which, from

its very nature, we know to be incomprehensible.

XLII. How, although we never will to err, it is nevertheless by our

will that we do err.

But now since we know that all our errors depend upon our will, and

as no one wishes to deceive himself, it may seem wonderful that

there is any error in our judgments at all. It is necessary to

remark, however, that there is a great difference between willing to

be deceived, and willing to yield assent to opinions in which it

happens that error is found. For though there is no one who

expressly wishes to fall into error, we will yet hardly find any one

who is not ready to assent to things in which, unknown to himself,

error lurks; and it even frequently happens that it is the desire

itself of following after truth that leads those not fully aware of

the order in which it ought to be sought for, to pass judgment on

matters of which they have no adequate knowledge, and thus to fall

into error.

XLIII. That we shall never err if we give our assent only to what

we clearly and distinctly perceive.

But it is certain we will never admit falsity for truth, so long as

we judge only of that which we clearly and distinctly perceive;

because, as God is no deceiver, the faculty of knowledge which he

has given us cannot be fallacious, nor, for the same reason, the

faculty of will, when we do not extend it beyond the objects we

clearly know. And even although this truth could not be established

by reasoning, the minds of all have been so impressed by nature as

spontaneously to assent to whatever is clearly perceived, and to

experience an impossibility to doubt of its truth.

XLIV. That we uniformly judge improperly when we assent to what we

do not clearly perceive, although our judgment may chance to be

true; and that it is frequently our memory which deceives us by

leading us to believe that certain things were formerly sufficiently

understood by us.

It is likewise certain that, when we approve of any reason which we

do not apprehend, we are either deceived, or, if we stumble on the

truth, it is only by chance, and thus we can never possess the

assurance that we are not in error. I confess it seldom happens that

we judge of a thing when we have observed we do not apprehend it,

because it is a dictate of the natural light never to judge of what

we do not know. But we most frequently err in this, that we presume

upon a past knowledge of much to which we give our assent, as to

something treasured up in the memory, and perfectly known to us;

whereas, in truth, we have no such knowledge.

XLV. What constitutes clear and distinct perception.

There are indeed a great many persons who, through their whole

lifetime, never perceive anything in a way necessary for judging of

it properly; for the knowledge upon which we can establish a certain

and indubitable judgment must be not only clear, but also, distinct.

I call that clear which is present and manifest to the mind giving

attention to it, just as we are said clearly to see objects when,

being present to the eye looking on, they stimulate it with

sufficient force. and it is disposed to regard them; but the

distinct is that which is so precise and different from all other

objects as to comprehend in itself only what is clear. [Footnote:

"what appears manifestly to him who considers it as he ought."--

FRENCH.]

XLVI. It is shown, from the example of pain, that a perception may

be clear without being distinct, but that it cannot be distinct

unless it is clear.

For example, when any one feels intense pain, the knowledge which he

has of this pain is very clear, but it is not always distinct; for

men usually confound it with the obscure judgment they form

regarding its nature, and think that there is in the suffering part

something similar to the sensation of pain of which they are alone

conscious. And thus perception may be clear without being distinct,

but it can never be distinct without likewise being clear.

XLVII. That, to correct the prejudices of our early years, we must

consider what is clear in each of our simple [Footnote: "first."--

FRENCH.] notions.

And, indeed, in our early years, the mind was so immersed in the

body, that, although it perceived many things with sufficient

clearness, it yet knew nothing distinctly; and since even at that

time we exercised our judgment in many matters, numerous prejudices

were thus contracted, which, by the majority, are never afterwards

laid aside. But that we may now be in a position to get rid of

these, I will here briefly enumerate all the simple notions of which

our thoughts are composed, and distinguish in each what is clear

from what is obscure, or fitted to lead into error.

XLVIII. That all the objects of our knowledge are to be regarded

either (1) as things or the affections of things: or (2) as eternal

truths; with the enumeration of things.

Whatever objects fall under our knowledge we consider either as

things or the affections of things,[Footnote: Things and the

affections of things are (in the French) equivalent to "what has

some (i.e., a REAL) existence," as opposed to the class of "eternal

truths," which have merely an IDEAL existence.] or as eternal truths

possessing no existence beyond our thought. Of the first class the

most general are substance, duration, order, number, and perhaps

also some others, which notions apply to all the kinds of things. I

do not, however, recognise more than two highest kinds (SUMMA

GENERA) of things; the first of intellectual things, or such as have

the power of thinking, including mind or thinking substance and its

properties; the second, of material things, embracing extended

substance, or body and its properties. Perception, volition, and all

modes as well of knowing as of willing, are related to thinking

substance; on the other hand, to extended substance we refer

magnitude, or extension in length, breadth, and depth, figure,

motion, situation, divisibility of parts themselves, and the like.

There are, however, besides these, certain things of which we have

an internal experience that ought not to be referred either to the

mind of itself, or to the body alone, but to the close and intimate

union between them, as will hereafter be shown in its place. Of this

class are the appetites of hunger and thirst, etc., and also the

emotions or passions of the mind which are not exclusively mental

affections, as the emotions of anger, joy, sadness, love, etc.; and,

finally, all the sensations, as of pain, titillation, light and

colours, sounds, smells, tastes, heat, hardness, and the other

tactile qualities.

XLIX. That the eternal truths cannot be thus enumerated, but that

this is not necessary.

What I have already enumerated we are to regard as things, or the

qualities or modes of things. We now come to speak of eternal

truths. When we apprehend that it is impossible a thing can arise

from nothing, this proposition, EX NIHILO NIHIL FIT, is not

considered as somewhat existing, or as the mode of a thing, but as

an eternal truth having its seat in our mind, and is called a common

notion or axiom. Of this class are the following:--It is impossible

the same thing can at once be and not be; what is done cannot be

undone; he who thinks must exist while he thinks; and innumerable

others, the whole of which it is indeed difficult to enumerate, but

this is not necessary, since, if blinded by no prejudices, we cannot

fail to know them when the occasion of thinking them occurs.

L. That these truths are clearly perceived, but not equally by all

men, on account of prejudices.

And, indeed, with regard to these common notions, it is not to be

doubted that they can be clearly and distinctly known, for otherwise

they would not merit this appellation: as, in truth, some of them

are not, with respect to all men, equally deserving of the name,

because they are not equally admitted by all: not, however, from

this reason, as I think, that the faculty of knowledge of one man

extends farther than that of another, but rather because these

common notions are opposed to the prejudices of some, who, on this

account, are not able readily to embrace them, even although others,

who are free from those prejudices, apprehend them with the greatest

clearness.

LI. What substance is, and that the term is not applicable to God

and the creatures in the same sense.

But with regard to what we consider as things or the modes of

things, it is worth while to examine each of them by itself. By

substance we can conceive nothing else than a thing which exists in

such a way as to stand in need of nothing beyond itself in order to

its existence. And, in truth, there can be conceived but one

substance which is absolutely independent, and that is God. We

perceive that all other things can exist only by help of the

concourse of God. And, accordingly, the term substance does not

apply to God and the creatures UNIVOCALLY, to adopt a term familiar

in the schools; that is, no signification of this word can be

distinctly understood which is common to God and them.

LII. That the term is applicable univocally to the mind and the

body, and how substance itself is known.

Created substances, however, whether corporeal or thinking, may be

conceived under this common concept; for these are things which, in

order to their existence, stand in need of nothing but the concourse

of God. But yet substance cannot be first discovered merely from its

being a thing which exists independently, for existence by itself is

not observed by us. We easily, however, discover substance itself

from any attribute of it, by this common notion, that of nothing

there are no attributes, properties, or qualities: for, from

perceiving that some attribute is present, we infer that some

existing thing or substance to which it may be attributed is also of

necessity present.

LIII. That of every substance there is one principal attribute, as

thinking of the mind, extension of the body.

But, although any attribute is sufficient to lead us to the

knowledge of substance, there is, however, one principal property of

every substance, which constitutes its nature or essence, and upon

which all the others depend. Thus, extension in length, breadth, and

depth, constitutes the nature of corporeal substance; and thought

the nature of thinking substance. For every other thing that can be

attributed to body, presupposes extension, and is only some mode of

an extended thing; as all the properties we discover in the mind are

only diverse modes of thinking. Thus, for example, we cannot

conceive figure unless in something extended, nor motion unless in

extended space, nor imagination, sensation, or will, unless in a

thinking thing. But, on the other hand, we can conceive extension

without figure or motion, and thought without imagination or

sensation, and so of the others; as is clear to any one who attends

to these matters.

LIV. How we may have clear and distinct notions of the substance

which thinks, of that which is corporeal, and of God.

And thus we may easily have two clear and distinct notions or ideas,

the one of created substance, which thinks, the other of corporeal

substance, provided we carefully distinguish all the attributes of

thought from those of extension. We may also have a clear and

distinct idea of an uncreated and independent thinking substance,

that is, of God, provided we do not suppose that this idea

adequately represents to us all that is in God, and do not mix up

with it anything fictitious, but attend simply to the characters

that are comprised in the notion we have of him, and which we

clearly know to belong to the nature of an absolutely perfect Being.

For no one can deny that there is in us such an idea of God, without

groundlessly supposing that there is no knowledge of God at all in

the human mind.

LV. How duration, order, and number may be also distinctly

conceived.

We will also have most distinct conceptions of duration, order, and

number, if, in place of mixing up with our notions of them that

which properly belongs to the concept of substance, we merely think

that the duration of a thing is a mode under which we conceive this

thing, in so far as it continues to exist; and, in like manner, that

order and number are not in reality different from things disposed

in order and numbered, but only modes under which we diversely

consider these things.

LVI. What are modes, qualities, attributes.

And, indeed, we here understand by modes the same with what we

elsewhere designate attributes or qualities. But when we consider

substance as affected or varied by them, we use the term modes; when

from this variation it may be denominated of such a kind, we adopt

the term qualities [to designate the different modes which cause it

to be so named]; and, finally, when we simply regard these modes as

in the substance, we call them attributes. Accordingly, since God

must be conceived as superior to change, it is not proper to say

that there are modes or qualities in him, but simply attributes; and

even in created things that which is found in them always in the

same mode, as existence and duration in the thing which exists and

endures, ought to be called attribute and not mode or quality.

LVII. That some attributes exist in the things to which they are

attributed, and others only in our thought; and what duration and

time are.

Of these attributes or modes there are some which exist in the

things themselves, and others that have only an existence in our

thought; thus, for example, time, which we distinguish from duration

taken in its generality, and call the measure of motion, is only a

certain mode under which we think duration itself, for we do not

indeed conceive the duration of things that are moved to be

different from the duration of things that are not moved: as is

evident from this, that if two bodies are in motion for an hour, the

one moving quickly and the other slowly, we do not reckon more time

in the one than in the other, although there may be much more motion

in the one of the bodies than in the other. But that we may

comprehend the duration of all things under a common measure, we

compare their duration with that of the greatest and most regular

motions that give rise to years and days, and which we call time;

hence what is so designated is nothing superadded to duration, taken

in its generality, but a mode of thinking.

LVIII. That number and all universals are only modes of thought.

In the same way number, when it is not considered as in created

things, but merely in the abstract or in general, is only a mode of

thinking; and the same is true of all those general ideas we call

universals.

LIX. How universals are formed; and what are the five common, viz.,

genus, species, difference, property, and accident.

Universals arise merely from our making use of one and the same idea

in thinking of all individual objects between which there subsists a

certain likeness; and when we comprehend all the objects represented

by this idea under one name, this term likewise becomes universal.

For example, when we see two stones, and do not regard their nature

farther than to remark that there are two of them, we form the idea

of a certain number, which we call the binary; and when we

afterwards see two birds or two trees, and merely take notice of

them so far as to observe that there are two of them, we again take

up the same idea as before, which is, accordingly, universal; and we

likewise give to this number the same universal appellation of

binary. In the same way, when we consider a figure of three sides,

we form a certain idea, which we call the idea of a triangle, and we

afterwards make use of it as the universal to represent to our mind

all other figures of three sides. But when we remark more

particularly that of figures of three sides, some have a right angle

and others not, we form the universal idea of a right-angled

triangle, which being related to the preceding as more general, may

be called species; and the right angle the universal difference by

which right-angled triangles are distinguished from all others; and

farther, because the square of the side which sustains the right

angle is equal to the squares of the other two sides, and because

this property belongs only to this species of triangles, we may call

it the universal property of the species. Finally, if we suppose

that of these triangles some are moved and others not, this will be

their universal accident; and, accordingly, we commonly reckon five

universals, viz., genus, species, difference, property, accident.

LX. Of distinctions; and first of the real.

But number in things themselves arises from the distinction there is

between them: and distinction is threefold, viz., real, modal, and

of reason. The real properly subsists between two or more

substances; and it is sufficient to assure us that two substances

are really mutually distinct, if only we are able clearly and

distinctly to conceive the one of them without the other. For the

knowledge we have of God renders it certain that he can effect all

that of which we have a distinct idea: wherefore, since we have now,

for example, the idea of an extended and corporeal substance, though

we as yet do not know with certainty whether any such thing is

really existent, nevertheless, merely because we have the idea of

it, we may be assured that such may exist; and, if it really exists,

that every part which we can determine by thought must be really

distinct from the other parts of the same substance. In the same

way, since every one is conscious that he thinks, and that he in

thought can exclude from himself every other substance, whether

thinking or extended, it is certain that each of us thus considered

is really distinct from every other thinking and corporeal

substance. And although we suppose that God united a body to a soul

so closely that it was impossible to form a more intimate union, and

thus made a composite whole, the two substances would remain really

distinct, notwithstanding this union; for with whatever tie God

connected them, he was not able to rid himself of the power he

possessed of separating them, or of conserving the one apart from

the other, and the things which God can separate or conserve

separately are really distinct.

LXI. Of the modal distinction.

There are two kinds of modal distinctions, viz., that between the

mode properly so-called and the substance of which it is a mode, and

that between two modes of the same substance. Of the former we have

an example in this, that we can clearly apprehend substance apart

from the mode which we say differs from it; while, on the other

hand, we cannot conceive this mode without conceiving the substance

itself. There is, for example, a modal distinction between figure or

motion and corporeal substance in which both exist; there is a

similar distinction between affirmation or recollection and the

mind. Of the latter kind we have an illustration in our ability to

recognise the one of two modes apart from the other, as figure apart

from motion, and motion apart from figure; though we cannot think of

either the one or the other without thinking of the common substance

in which they adhere. If, for example, a stone is moved, and is

withal square, we can, indeed, conceive its square figure without

its motion, and reciprocally its motion without its square figure;

but we can conceive neither this motion nor this figure apart from

the substance of the stone. As for the distinction according to

which the mode of one substance is different from another substance,

or from the mode of another substance, as the motion of one body is

different from another body or from the mind, or as motion is

different from doubt, it seems to me that it should be called real

rather than modal, because these modes cannot be clearly conceived

apart from the really distinct substances of which they are the

modes.

LXII. Of the distinction of reason (logical distinction).

Finally, the distinction of reason is that between a substance and

some one of its attributes, without which it is impossible, however,

we can have a distinct conception of the substance itself; or

between two such attributes of a common substance, the one of which

we essay to think without the other. This distinction is manifest

from our inability to form a clear and distinct idea of such

substance, if we separate from it such attribute; or to have a clear

perception of the one of two such attributes if we separate it from

the other. For example, because any substance which ceases to endure

ceases also to exist, duration is not distinct from substance except

in thought (RATIONE); and in general all the modes of thinking which

we consider as in objects differ only in thought, as well from the

objects of which they are thought as from each other in a common

object.[Footnote: "and generally all the attributes that lead us to

entertain different thoughts of the same thing, such as, for

example, the extension of body and its property of divisibility, do

not differ from the body which is to us the object of them, or from

each other, unless as we sometimes confusedly think the one without

thinking the other."--FRENCH.] It occurs, indeed, to me that I have

elsewhere classed this kind of distinction with the modal (viz.,

towards the end of the Reply to the First Objections to the

Meditations on the First Philosophy); but there it was only

necessary to treat of these distinctions generally, and it was

sufficient for my purpose at that time simply to distinguish both of

them from the real.

LXIII. How thought and extension may be distinctly known, as

constituting, the one the nature of mind, the other that of body.

Thought and extension may be regarded as constituting the natures of

intelligent and corporeal substance; and then they must not be

otherwise conceived than as the thinking and extended substances

themselves, that is, as mind and body, which in this way are

conceived with the greatest clearness and distinctness. Moreover, we

more easily conceive extended or thinking substance than substance

by itself, or with the omission of its thinking or extension. For

there is some difficulty in abstracting the notion of substance from

the notions of thinking and extension, which, in truth, are only

diverse in thought itself (i.e., logically different); and a concept

is not more distinct because it comprehends fewer properties, but

because we accurately distinguish what is comprehended in it from

all other notions.

LXIV. How these may likewise be distinctly conceived as modes of

substance.

Thought and extension may be also considered as modes of substance;

in as far, namely, as the same mind may have many different

thoughts, and the same body, with its size unchanged, may be

extended in several diverse ways, at one time more in length and

less in breadth or depth, and at another time more in breadth and

less in length; and then they are modally distinguished from

substance, and can be conceived not less clearly and distinctly,

provided they be not regarded as substances or things separated from

others, but simply as modes of things. For by regarding them as in

the substances of which they are the modes, we distinguish them from

these substances, and take them for what in truth they are: whereas,

on the other hand, if we wish to consider them apart from the

substances in which they are, we should by this itself regard them

as self-subsisting things, and thus confound the ideas of mode and

substance.

LXV. How we may likewise know their modes.

In the same way we will best apprehend the diverse modes of thought,

as intellection, imagination, recollection, volition, etc., and also

the diverse modes of extension, or those that belong to extension,

as all figures, the situation of parts and their motions, provided

we consider them simply as modes of the things in which they are;

and motion as far as it is concerned, provided we think merely of

locomotion, without seeking to know the force that produces it, and

which nevertheless I will essay to explain in its own place.

LXVI. How our sensations, affections, and appetites may be clearly

known, although we are frequently wrong in our judgments regarding

them.

There remain our sensations, affections, and appetites, of which we

may also have a clear knowledge, if we take care to comprehend in

the judgments we form of them only that which is precisely contained

in our perception of them, and of which we are immediately

conscious. There is, however, great difficulty in observing this, at

least in respect of sensations; because we have all, without

exception, from our youth judged that all the things we perceived by

our senses had an existence beyond our thought, and that they were

entirely similar to the sensations, that is, perceptions, we had of

them. Thus when, for example, we saw a certain colour, we thought we

saw something occupying a place out of us, and which was entirely

similar to that idea of colour we were then conscious of; and from

the habit of judging in this way, we seemed to see this so clearly

and distinctly that we esteemed it (i.e., the externality of the

colour) certain and indubitable.

LXVII. That we are frequently deceived in our judgments regarding

pain itself.

The same prejudice has place in all our other sensations, even in

those of titillation and pain. For though we are not in the habit of

believing that there exist out of us objects that resemble

titillation and pain, we do not nevertheless consider these

sensations as in the mind alone, or in our perception, but as in the

hand, or foot, or some other part of our body. There is no reason,

however, to constrain us to believe that the pain, for example,

which we feel, as it were, in the foot is something out of the mind

existing in the foot, or that the light which we see, as it were, in

the sun exists in the sun as it is in us. Both these beliefs are

prejudices of our early years, as will clearly appear in the sequel.

LXVIII. How in these things what we clearly conceive is to be

distinguished from that in which we may be deceived.

But that we may distinguish what is clear in our sensations from

what is obscure, we ought most carefully to observe that we possess

a clear and distinct knowledge of pain, colour, and other things of

this sort, when we consider them simply as sensations or thoughts;

but that, when they are judged to be certain things subsisting

beyond our mind, we are wholly unable to form any conception of

them. Indeed, when any one tells us that he sees colour in a body or

feels pain in one of his limbs, this is exactly the same as if he

said that he there saw or felt something of the nature of which he

was entirely ignorant, or that he did not know what he saw or felt.

For although, when less attentively examining his thoughts, a person

may easily persuade himself that he has some knowledge of it, since

he supposes that there is something resembling that sensation of

colour or of pain of which he is conscious; yet, if he reflects on

what the sensation of colour or pain represents to him as existing

in a coloured body or in a wounded member, he will find that of such

he has absolutely no knowledge.

LXIX. That magnitude, figure, etc., are known far differently from

colour, pain, etc.

What we have said above will be more manifest; especially if we

consider that size in the body perceived, figure, motion (at least

local, for philosophers by fancying other kinds of motion have

rendered its nature less intelligible to themselves), the situation

of parts, duration, number, and those other properties which, as we

have already said, we clearly perceive in all bodies, are known by

us in a way altogether different from that in which we know what

colour is in the same body, or pain, smell, taste, or any other of

those properties which I have said above must be referred to the

senses. For although when we see a body we are not less assured of

its existence from its appearing figured than from its appearing

coloured,[Footnote: "by the colour we perceive on occasion of it."--

FRENCH.] we yet know with far greater clearness its property of

figure than its colour.

LXX. That we may judge of sensible things in two ways, by the one

of which we avoid error, by the other fall into it.

It is thus manifest that to say we perceive colours in objects is in

reality equivalent to saying we perceive something in objects and

are yet ignorant of what it is, except as that which determines in

us a certain highly vivid and clear sensation, which we call the

sensation of colours. There is, however, very great diversity in the

manner of judging: for so long as we simply judge that there is an

unknown something in objects (that is, in things such as they are,

from which the sensation reached us), so far are we from falling

into error that, on the contrary, we thus rather provide against it,

for we are less apt to judge rashly of a thing which we observe we

do not know. But when we think we perceive colours in objects,

although we are in reality ignorant of what we then denominate

colour, and are unable to conceive any resemblance between the

colour we suppose to be in objects, and that of which we are

conscious in sensation, yet because we do not observe this, or

because there are in objects several properties, as size, figure,

number, etc., which, as we clearly know, exist, or may exist in them

as they are perceived by our senses or conceived by our

understanding, we easily glide into the error of holding that what

is called colour in objects is something entirely resembling the

colour we perceive, and thereafter of supposing that we have a clear

perception of what is in no way perceived by us.

LXXI. That the chief cause of our errors is to be found in the

prejudices of our childhood.

And here we may notice the first and chief cause of our errors. In

early life the mind was so closely bound to the body that it

attended to nothing beyond the thoughts by which it perceived the

objects that made impression on the body; nor as yet did it refer

these thoughts to anything existing beyond itself, but simply felt

pain when the body was hurt, or pleasure when anything beneficial to

the body occurred, or if the body was so highly affected that it was

neither greatly benefited nor hurt, the mind experienced the

sensations we call tastes, smells, sounds, heat, cold, light,

colours, and the like, which in truth are representative of nothing

existing out of our mind, and which vary according to the

diversities of the parts and modes in which the body is affected.

[Footnote: "which vary according to the diversities of the movements

that pass from all parts of our body to the part of the brain to

which it (the mind) is closely joined and united."--FRENCH.] The

mind at the same time also perceived magnitudes, figures, motions,

and the like, which were not presented to it as sensations but as

things or the modes of things existing, or at least capable of

existing out of thought, although it did not yet observe this

difference between these two kinds of perceptions. And afterwards

when the machine of the body, which has been so fabricated by nature

that it can of its own inherent power move itself in various ways,

by turning itself at random on every side, followed after what was

useful and avoided what was detrimental; the mind, which was closely

connected with it, reflecting on the objects it pursued or avoided,

remarked, for the first time, that they existed out of itself, and

not only attributed to them magnitudes, figures, motions, and the

like, which it apprehended either as things or as the modes of

things, but, in addition, attributed to them tastes, odours, and the

other ideas of that sort, the sensations of which were caused by

itself; [Footnote: "which it perceived on occasion of them" (i.e.,

of external objects).--FRENCH.] and as it only considered other

objects in so far as they were useful to the body, in which it was

immersed, it judged that there was greater or less reality in each

object, according as the impressions it caused on the body were more

or less powerful. Hence arose the belief that there was more

substance or body in rocks and metals than in air or water, because

the mind perceived in them more hardness and weight. Moreover, the

air was thought to be merely nothing so long as we experienced no

agitation of it by the wind, or did not feel it hot or cold. And

because the stars gave hardly more light than the slender flames of

candles, we supposed that each star was but of this size. Again,

since the mind did not observe that the earth moved on its axis, or

that its superficies was curved like that of a globe, it was on that

account more ready to judge the earth immovable and its surface

flat. And our mind has been imbued from our infancy with a thousand

other prejudices of the same sort which afterwards in our youth we

forgot we had accepted without sufficient examination, and admitted

as possessed of the highest truth and clearness, as if they had been

known by means of our senses, or implanted in us by nature.

LXXII. That the second cause of our errors is that we cannot forget

these prejudices.

And although now in our mature years, when the mind, being no longer

wholly subject to the body, is not in the habit of referring all

things to it, but also seeks to discover the truth of things

considered in themselves, we observe the falsehood of a great many

of the judgments we had before formed; yet we experience a

difficulty in expunging them from our memory, and, so long as they

remain there, they give rise to various errors. Thus, for example,

since from our earliest years we imagined the stars to be of very

small size, we find it highly difficult to rid ourselves of this

imagination, although assured by plain astronomical reasons that

they are of the greatest,--so prevailing is the power of

preconceived opinion.

LXXIII. The third cause is, that we become fatigued by attending to

those objects which are not present to the senses; and that we are

thus accustomed to judge of these not from present perception but

from pre-conceived opinion.

Besides, our mind cannot attend to any object without at length

experiencing some pain and fatigue; and of all objects it has the

greatest difficulty in attending to those which are present neither

to the senses nor to the imagination: whether for the reason that

this is natural to it from its union with the body, or because in

our early years, being occupied merely with perceptions and

imaginations, it has become more familiar with, and acquired greater

facility in thinking in those modes than in any other. Hence it also

happens that many are unable to conceive any substance except what

is imaginable and corporeal, and even sensible. For they are

ignorant of the circumstance, that those objects alone are

imaginable which consist in extension, motion, and figure, while

there are many others besides these that are intelligible; and they

persuade themselves that nothing can subsist but body, and, finally,

that there is no body which is not sensible. And since in truth we

perceive no object such as it is by sense alone [but only by our

reason exercised upon sensible objects], as will hereafter be

clearly shown, it thus happens that the majority during life

perceive nothing unless in a confused way.

LXXIV. The fourth source of our errors is, that we attach our

thoughts to words which do not express them with accuracy.

Finally, since for the use of speech we attach all our conceptions

to words by which to express them, and commit to memory our thoughts

in connection with these terms, and as we afterwards find it more

easy to recall the words than the things signified by them, we can

scarcely conceive anything with such distinctness as to separate

entirely what we conceive from the words that were selected to

express it. On this account the majority attend to words rather than

to things; and thus very frequently assent to terms without

attaching to them any meaning, either because they think they once

understood them, or imagine they received them from others by whom

they were correctly understood. This, however, is not the place to

treat of this matter in detail, seeing the nature of the human body

has not yet been expounded, nor the existence even of body

established; enough, nevertheless, appears to have been said to

enable one to distinguish such of our conceptions as are clear and

distinct from those that are obscure and confused.

LXXV. Summary of what must be observed in order to philosophize

correctly.

Wherefore if we would philosophize in earnest, and give ourselves to

the search after all the truths we are capable of knowing, we must,

in the first place, lay aside our prejudices; in other words, we

must take care scrupulously to withhold our assent from the opinions

we have formerly admitted, until upon new examination we discover

that they are true. We must, in the next place, make an orderly

review of the notions we have in our minds, and hold as true all and

only those which we will clearly and distinctly apprehend. In this

way we will observe, first of all, that we exist in so far as it is

our nature to think, and at the same time that there is a God upon

whom we depend; and after considering his attributes we will be able

to investigate the truth of all other things, since God is the cause

of them. Besides the notions we have of God and of our mind, we will

likewise find that we possess the knowledge of many propositions

which are eternally true, as, for example, that nothing cannot be

the cause of anything, etc. We will farther discover in our minds

the knowledge of a corporeal or extended nature that may be moved,

divided, etc., and also of certain sensations that affect us, as of

pain, colours, tastes, etc., although we do not yet know the cause

of our being so affected; and, comparing what we have now learne'd,

by examining those things in their order, with our former confused

knowledge of them, we will acquire the habit of forming clear and

distinct conceptions of all the objects we are capable of knowing.

In these few precepts seem to me to be comprised the most general

and important principles of human knowledge.

LXXVI. That we ought to prefer the Divine authority to our

perception; [Footnote: "reasonings."--FRENCH]. but that, apart from

things revealed, we ought to assent to nothing that we do not

clearly apprehend.

Above all, we must impress on our memory the infallible rule, that

what God has revealed is incomparably more certain than anything

else; and that, we ought to submit our belief to the Divine

authority rather than to our own judgment, even although perhaps the

light of reason should, with the greatest clearness and evidence,

appear to suggest to us something contrary to what is revealed. But

in things regarding which there is no revelation, it is by no means

consistent with the character of a philosopher to accept as true

what he has not ascertained to be such, and to trust more to the

senses, in other words, to the inconsiderate judgments of childhood

than to the dictates of mature reason.