extraordinary power in one domain, there is a tendency to credit it
with similar power in all other domains. Thus theologians have
found comfort and assurance in the thought that Newton dealt with
the question of revelation--forgetful of the fact that the very
devotion of his powers, through all the best years of his life, to
a totally different class of ideas, not to speak of any natural
disqualification, tended to render him less, instead of more competent
to deal with theological and historic questions. Goethe, starting
from his established greatness as a poet, and indeed from his positive
discoveries in Natural History, produced a profound impression among
the painters of Germany, when he published his 'Farbenlehre,' in
which he endeavoured to overthrow Newton's theory of colours. This
theory he deemed so obviously absurd, that he considered its author a
charlatan, and attacked him with a corresponding vehemence of
language.
In the domain of Natural History, Goethe had made really considerable
discoveries; and we have high authority for assuming that, had he
devoted himself wholly to that side of science, he might have reached
an eminence comparable with that which he attained as a poet. In
sharpness of observation, in the detection of analogies apparently
remote, in the classification and organisation of facts according to
the analogies discerned, Goethe possessed extraordinary powers. These
elements of scientific enquiry fall in with the disciplines of the
poet. But, on the other hand, a mind thus richly endowed in the
direction of natural history, may be almost shorn of endowment as
regards the physical and mechanical sciences. Goethe was in this
condition. He could not formulate distinct mechanical conceptions; he
could not see the force of mechanical reasoning; and, in regions where
such reasoning reigns supreme, he became a mere ignis fatuus to those
who followed him.
I have sometimes permitted myself to compare Aristotle with Goethe--to
credit the Stagirite with an almost superhuman power of amassing and
systematising facts, but to consider him fatally defective on that
side of the mind, in respect to which incompleteness has been just
ascribed to Goethe. Whewell refers the errors of Aristotle not to a
neglect of facts, but to 'a neglect of the idea appropriate to the
facts: the idea of Mechanical cause, which is Force, and the
substitution of vague or inapplicable notions, involving only
relations of space or emotions of wonder.' This is doubtless true; but
the word 'neglect' implies mere intellectual misdirection, whereas in
Aristotle, as in Goethe, it was not, I believe, misdirection, but
sheer natural incapacity which lay at the root of his mistakes. As a
physicist, Aristotle displayed what we should consider some of the
worst of attributes in a modern physical investigator--indistinctness
of ideas, confusion of mind, and a confident use of language which led
to the delusive notion that he had really mastered his subject, while
he had, as yet, failed to grasp even the elements of it. He put
words in the place of things, subject in the place of object. He
preached Induction without practising it, inverting the true order of
enquiry, by passing from the general to the particular, instead of
from the particular to the general. He made of the universe a closed
sphere, in the centre of which he fixed the earth, proving from
general principles, to his own satisfaction and to that of the world
for near 2,000 years, that no other universe was possible. His
notions of motion were entirely unphysical. It was natural or
unnatural, better or worse, calm or violent--no real mechanical
conception regarding it lying at the bottom of his mind.
He affirmed that a vacuum could not exist, and proved that if it did
motion in it would be impossible. He determined _à priori_ how many
species of animals must exist, and showed on general principles why
animals must have such and such parts. When an eminent contemporary
philosopher, who is far removed from errors of this kind, remembers
these abuses of the _à priori_ method, he will be able to make allowance
for the jealousy of physicists as to the acceptance of so-called _à
priori_ truths. Aristotle's errors of detail, as shown by Eucken and
Lange, were grave and numerous. He affirmed that only in man we had
the beating of the heart, that the left side of the body was colder
than the right, that men have more teeth than women, and that there is
an empty space at the back of every man's head.
There is one essential quality in physical conceptions, which was
entirely wanting in those of Aristotle and his followers--a capability
of being placed as coherent pictures before the mind. The Germans
express the act of picturing by the word vorstellen, and the picture
they call a Vorstellung. We have no word in English which comes
nearer to our requirements than Imagination; and, taken with its
proper limitations, the word answers very well. But it is tainted by
its associations, and therefore objectionable to some minds. Compare,
with reference to this capacity of mental presentation, the case of
the Aristotelian, who refers the ascent of water in a pump to Nature's
abhorrence of a vacuum, with that of Pascal when he proposed to solve
the question of atmospheric pressure by the ascent of the Puy de Dôme.
In the one case the terms of the explanation refuse to fall into place
as a physical image; in the other the image is distinct, the descent
and rise of the barometer being clearly figured beforehand as the
balancing of two varying and opposing pressures.
3.
During the drought of the Middle Ages in Christendom, the Arabian
intellect, as forcibly shown by Draper, was active. With the
intrusion of the Moors into Spain, order, learning, and refinement
took the place of their opposites. When smitten with disease, the
Christian peasant resorted to a shrine, the Moorish one to an
instructed physician. The Arabs encouraged translations from the
Greek philosophers, but not from the Greek poets. They turned in
disgust 'from the lewdness of our classical mythology, and denounced
as an unpardonable blasphemy all connection between the impure
Olympian Jove and the Most High God.' Draper traces still farther
than Whewell the Arab elements in our scientific terms. He gives
examples of what Arabian men of science accomplished, dwelling
particularly on Alhazen, who was the first to correct the Platonic
notion that rays of light are emitted by the eye. Alhazen discovered
atmospheric refraction, and showed that we see the sun and the moon
after they have set. He explained the enlargement of the sun and
moon, and the shortening of the vertical diameters of both these
bodies when near the horizon. He was aware that the atmosphere
decreases in density with increase of elevation, and actually fixed
its height at 58.5 miles. In the 'Book of the Balance of Wisdom,' he
sets forth the connection between the weight of the atmosphere and its
increasing density. He shows that a body will weigh differently in a
rare and dense atmosphere, and he considers the force with which
plunged bodies rise through heavier media. He understood the doctrine
of the centre of gravity, and applied it to the investigation of
balances and steelyards. He recognised gravity as a. force, though
he fell into the error of assuming it to diminish simply as the
distance, and of making it purely terrestrial. He knew the relation
between the velocities, spaces, and times of falling bodies, and had
distinct ideas of capillary attraction. He improved the hydrometer.
The determinations of the densities of bodies, as given by Alhazen,
approach very closely to our own. 'I join,' says Draper, 'in the
pious prayer of Alhazen, that in the day of judgment the All-Merciful
will take pity on the soul of Abur-Raihân, because he was the first of
the race of men to construct a table of specific gravities.' If all
this be historic truth (and I have entire confidence in Dr. Draper),
well may he 'deplore the systematic manner in which the literature of
Europe has, contrived to put out of sight our scientific obligations
to the Mahommedans.' [Footnote: Intellectual Development of Europe,'
p. 359.]
The strain upon the mind during the stationary period towards
ultra-terrestrial things, to the neglect of problems close at hand,
was sure to provoke reaction. But the reaction was gradual; for the
ground was dangerous, and a power was at hand competent to crush the
critic who went too far. To elude this power, and still allow
opportunity for the expression of opinion, the doctrine of 'two-fold
truth' was invented, according to which an opinion might be held
'theologically,' and the opposite opinion 'philosophically.'
[Footnote: 'Lange,' 2nd edit. pp. 181, 182.] Thus, in the thirteenth
century, the creation of the world in six days, and the
unchangeableness of the individual soul, which had been so distinctly
affirmed by St. Thomas Aquinas, were both denied philosophically, but
admitted to be true as articles of the Catholic faith. When
Protagoras uttered the maxim which brought upon him so much
vituperation, that 'opposite assertions are equally true,' he simply
meant to affirm men's differences to be so great, that what was
subjectively true to the one might be subjectively untrue to the
other. The great Sophist never meant to play fast and loose with the
truth by saying that one of two opposite assertions, made by the same
individual, could possibly escape being a lie. It was not
'sophistry,' but the dread of theologic vengeance, that generated this
double dealing with conviction; and it is astonishing to notice what
lengths were allowed to men who were adroit in the use of artifices
of this kind.
Towards the close of the stationary period a word-weariness, if I may
so express it, took more and more possession of men's minds.
Christendom had become sick of the School Philosophy and its verbal
wastes, which led to no issue, but left the intellect in everlasting
haze. Here and there was heard the voice of one impatiently crying in
the wilderness, 'Not unto Aristotle, not unto subtle hypothesis, not
unto church, Bible, or blind tradition, must we turn for a knowledge
of the universe, but to the direct investigation of nature by
observation and experiment.' In 1543 the epoch-marking work of
Copernicus on the paths of the heavenly bodies appeared. The total
crash of Aristotle's closed universe, with the earth at its centre,
followed as a consequence, and 'The earth moves!' became a kind of
watchword among intellectual freemen. Copernicus was Canon of the
church of Frauenburg in the diocese of Ermeland. For three-and-thirty
years he had withdrawn himself from the world, and devoted himself to
the consolidation of his great scheme of the solar system. He made
its blocks eternal; and even to those who feared it, and desired its
overthrow, it was so obviously strong, that they refrained for a time
from meddling with it. In the last year of the life of Copernicus his
book appeared: it is said that the old man received a copy of it a few
days before his death, and then departed in peace.
The Italian philosopher, Giordano Bruno, was one of the earliest
converts to the new astronomy. Taking Lucretius as his exemplar, he
revived the notion of the infinity of worlds; and, combining with it
the doctrine of Copernicus, reached the sublime generalisation that
the fixed stars are suns, scattered numberless through space, and
accompanied by satellites, which bear the same relation to them that
our earth does to our sun, or our moon to our earth. This was an
expansion of transcendent import; but Bruno came closer than this to
our present line of thought. Struck with the problem of the
generation and maintenance of organisms, and duly pondering it, he
came to the conclusion that Nature, in her productions, does not
imitate the technic of man. Her process is one of unravelling and
unfolding. The infinity of forms under which matter appears was not
imposed upon it by an external artificer; by its own intrinsic force
and virtue it brings these forms forth. Matter is not the mere naked,
empty capacity which philosophers have pictured her to be, but the
universal mother, who brings forth all things as the fruit of her own
womb.
This outspoken man was originally a Dominican monk. He was accused of
heresy and had to fly, seeking refuge in Geneva, Paris, England, and
Germany. In 1592 be fell into the hands of the Inquisition at Venice.
He was imprisoned for many years, tried, degraded, excommunicated, and
handed over to the Civil power, with the request that he should be
treated gently, and 'without the shedding of blood.' This meant that
he was to be burnt; and burnt accordingly he was, on February 16,
1600. To escape a similar fate Galileo, thirty-three years
afterwards, abjured upon his knees, with his hands upon the holy
Gospels, the heliocentric doctrine, which he knew to be true. After
Galileo came Kepler, who from his German home defied the ultramontane
power. He traced out from pre-existing observations the laws of
planetary motion. Materials were thus prepared for Newton, who bound
those empirical laws together by the principle of gravitation.
4.
In the seventeenth century Bacon and Descartes, the restorers of
philosophy, appeared in succession. Differently educated and endowed,
their philosophic tendencies were different. Bacon held fast to
Induction, believing firmly in the existence of an external world, and
making collected experiences the basis of all knowledge. The
mathematical studies of Descartes gave him a bias towards Deduction;
and his fundamental principle was much the same as that of Protagoras,
who 'made the individual man the measure of all things. I think,
therefore I am,' said Descartes. Only his own identity was sure to
him; and the full development of this system would have led to an
idealism, in which the outer world would have been resolved into a
mere phenomenon of consciousness. Gassendi, one of Descartes's
contemporaries, of whom we shall hear more presently, quickly pointed
out that the fact of personal existence would be proved as well by
reference to any other act, as to the act of thinking. I eat,
therefore I am, or I love, therefore I am, would be quite as
conclusive. Lichtenberg, indeed, showed that the very thing to be
proved was inevitably postulated in the first two words, 'I think;'
and it is plain that no inference from the postulate could, by any
possibility, be stronger than the postulate itself.
But Descartes deviated strangely from the idealism implied in his
fundamental principle. He was the first to reduce, in a manner
eminently capable of bearing the test of mental presentation, vital
phenomena to purely mechanical principles. Through fear or love,
Descartes was a good churchman; he accordingly rejected the notion of
an atom, because it was absurd to suppose that God, if He so pleased,
could not divide an atom; he puts in the place-of the atoms small
round particles, and light splinters, out of which he builds the
organism. He sketches with marvellous physical insight a machine,
with water for its motive power, which shall illustrate vital actions.
He has made clear to his mind that such a machine would be competent
to carry on the processes of digestion, nutrition, growth,
respiration, and the beating of the heart. It would be competent to
accept impressions from the external sense, to store them up in
imagination and memory, to go through the internal movements of the
appetites and passions, and the external movements of the limbs. He
deduces these functions of his machine from the mere arrangements of
its organs, as the movement of a clock, or other automaton, is deduced
from its weights and wheels. As far as these functions are
concerned,' he says, 'it is not necessary to conceive any other
vegetative or sensitive soul, nor any other principle of motion or of
life, than the blood and the spirits agitated by the fire which burns
continually in the heart, and which is in nowise different from the
fires existing in inanimate bodies.' Had Descartes been acquainted
with the steam-engine, he would have taken it, instead of a fall of
water, as his motive power. He would have shown the perfect analogy
which exists between the oxidation of the food in the body, and that
of the coal in the furnace. He would assuredly have anticipated Mayer
in calling the blood which the heart diffuses, 'the oil of the lamp of
life,' deducing all animal motions from the combustion of this oil, as
the motions of a steam-engine are deduced from the combustion of its
coal. As the matter stands, however, and considering the
circumstances of the time, the boldness, clearness, and precision,
with which Descartes grasped the problem of vital dynamics constitute
a marvellous illustration of intellectual power. [Footnote: See
Huxley's admirable 'Essay on Descartes.' Lay Sermons.]
During the Middle Ages the doctrine of atoms had to all appearance
vanished from discussion. It probably held its ground among
sober-minded and thoughtful men, though neither the church nor the
world was prepared to hear of it with tolerance. Once, in the year
1348, it received distinct expression. But retractation by compulsion
immediately followed; and, thus discouraged, it slumbered till the
seventeenth century, when it was revived by a contemporary and friend
of Hobbes of Malmesbury, the orthodox Catholic provost of Digne,
Gassendi. But, before stating his relation to the Epicurean doctrine,
it will be well to say a few words on the effect, as regards science,
of the general introduction of monotheism among European nations.
'Were men,' says Hume, 'led into the apprehension of invisible
intelligent power by contemplation of the works of Nature, they could
never possibly entertain any conception but of one single Being, who
bestowed existence and order on this vast machine, and adjusted all
its parts to one regular system.' Referring to the condition of the
heathen, who sees a god behind every natural event, thus peopling the
world with thousands of beings whose caprices are incalculable, Lange
shows the impossibility of any compromise between such notions and
those of science, which proceeds on the assumption of never-changing
law and causality. 'But,' he continues, with characteristic
penetration, 'when the great thought of one God, acting as a unit upon
the universe, has been seized, the connection of things in accordance
with the law of cause and effect is not only thinkable, but it is a
necessary consequence of the assumption. For when I see ten thousand
wheels in motion, and know, or believe, that they are all driven by
one motive power, then I know that I have before me a mechanism, the
action of every part of which is determined by the plan of the whole.
So much being assumed, it follows that I may investigate the structure
of that machine, and the various motions of its parts. For the time
being, therefore, this conception renders scientific action free.' In
other words, were a capricious God at the circumference of every wheel
and at the end of every lever, the action of the machine would be
incalculable by the methods of science. But the actions of all its
parts being rigidly determined by their connections and relations, and
these being brought into play by a single motive power, then though
this last prime mover may elude me, I am still able to comprehend the
machinery which it sets in motion. We have here a conception of the
relation of Nature to its Author, which seems perfectly acceptable to
some minds, but perfectly intolerable to others. Newton and Boyle
lived and worked happily under the influence of this conception;
Goethe rejected it with vehemence, and the same repugnance to
accepting it is manifest in Carlyle. [Footnote: Boyle's model of the
universe was the Strasburg clock with an outside Artificer. Goethe,
on the other hand, sang:
'Ihm ziemt's die Welt im Innern zu bewegen,
Natur in sich, sich in Natur zu hegen.'
See also Carlyle, 'Past and Present,' chap. v.]
The analytic and synthetic tendencies of the human mind are traceable
throughout history, great writers ranging themselves sometimes on the
one side, sometimes on the other. Men of warm feelings, and minds
open to the elevating impressions produced by nature as a whole, whose
satisfaction, therefore, is rather ethical than logical, lean to the
synthetic side; while the analytic harmonises best with the more
precise and more mechanical bias which seeks the satisfaction of the
understanding. Some form of pantheism was usually adopted by the one,
while a detached Creator, working more or less after the manner of
men, was often assumed by the other. Gassendi, as sketched by Lange,
is hardly to be ranked with either. Having formally acknowledged God
as the great first cause, he immediately dropped the idea, applied the
known laws of mechanics to the atoms, and deduced from them all vital
phenomena. He defended Epicurus, and dwelt upon his purity, both of
doctrine and of life. True he was a heathen, but so was Aristotle.
Epicurus assailed superstition and religion, and rightly, because he
did not know the true religion. He thought that the gods neither
rewarded nor punished, and he adored them purely in consequence of
their completeness: here we see, says Gassendi, the reverence of the
child, instead of the fear of the slave. The errors of Epicurus shall
be corrected, and the body of his truth retained. Gassendi then
proceeds, as any heathen might have done, to build up the world, and
all that therein is, of atoms and molecules. God, who created earth
and water, plants and animals, produced in the first place a definite
number of atoms, which constituted the seed of all things. Then began
that series of combinations and decompositions which now goes on, and
which will continue in future. The principle of every change resides
in matter. In artificial productions the moving principle is
different from the material worked upon; but in nature the agent works
within, being the most active and mobile part of the material itself.
Thus this bold ecclesiastic, without incurring the censure of the
church or the world, contrives to outstrip Mr. Darwin. The same cast
of mind which caused him to detach the Creator from his universe, led
him also to detach the soul from the body, though to the body he
ascribes an influence so large as to render the soul almost
unnecessary. The aberrations of reason were, in his view, an affair
of the material brain. Mental disease is brain disease; but then the
immortal reason sits apart, and cannot be touched by the disease. The
errors of madness are those of the instrument, not of the performer.
It may be more than a mere result of education, connecting itself,
probably, with the deeper mental structure of the two men, that the
idea of Gassendi, above enunciated, is substantially the same as that
expressed by Professor Clerk Maxwell, at the close of the very able
lecture delivered by him at Bradford in 1873. According to both
philosophers, the atoms, if I understand aright, are prepared
materials, which, formed once for all by the Eternal, produce by their
subsequent interaction all the phenomena of the material world. There
seems to be this difference, however, between Gassendi and Maxwell.
The one postulates, the other infers his first cause. In his
'manufactured articles,' as he calls the atoms, Professor Maxwell
finds the basis of an induction, which enables him to scale
philosophic heights considered inaccessible by Kant, and to take the
logical step from the atoms to their Maker.
Accepting here the leadership of Kant, I doubt the legitimacy of
Maxwell's logic; but it is impossible not to feel the ethic glow with
which his lecture concludes. There is, moreover, a very noble strain
of eloquence in his description of the steadfastness of the atoms:
Natural causes, as we know, are at work, which tend to modify, if they
do not at length destroy, all the arrangements and dimensions of the
earth and the whole solar system. But though in the course of ages
catastrophes have occurred and may yet occur in the heavens, though
ancient systems may be dissolved and new systems evolved out of their
ruins, the molecules out of which these systems are built--the
foundation stones of the material universe--remain unbroken and
unworn.'