Nature in the aspect which she presented to a Greek philosopher
of the fourth century before Christ is not easily reproduced to
modern eyes. The associations of mythology and poetry have to be
added, and the unconscious influence of science has to be
subtracted, before we can behold the heavens or the earth as they
appeared to the Greek. The philosopher himself was a child and
also a man—a child in the range of his attainments, but also a
great intelligence having an insight into nature, and often
anticipations of the truth. He was full of original thoughts, and
yet liable to be imposed upon by the most obvious fallacies. He
occasionally confused numbers with ideas, and atoms with numbers;
his a priori notions were out of all proportion to his
experience. He was ready to explain the phenomena of the heavens
by the most trivial analogies of earth. The experiments which
nature worked for him he sometimes accepted, but he never tried
experiments for himself which would either prove or disprove his
theories. His knowledge was unequal; while in some branches, such
as medicine and astronomy, he had made considerable proficiency,
there were others, such as chemistry, electricity, mechanics, of
which the very names were unknown to him. He was the natural
enemy of mythology, and yet mythological ideas still retained
their hold over him. He was endeavouring to form a conception of
principles, but these principles or ideas were regarded by him as
real powers or entities, to which the world had been subjected.
He was always tending to argue from what was near to what was
remote, from what was known to what was unknown, from man to the
universe, and back again from the universe to man. While he was
arranging the world, he was arranging the forms of thought in his
own mind; and the light from within and the light from without
often crossed and helped to confuse one another. He might be
compared to a builder engaged in some great design, who could
only dig with his hands because he was unprovided with common
tools; or to some poet or musician, like Tynnichus (Ion), obliged
to accommodate his lyric raptures to the limits of the tetrachord
or of the flute.
The Hesiodic and Orphic cosmogonies were a phase of thought
intermediate between mythology and philosophy and had a great
influence on the beginnings of knowledge. There was nothing
behind them; they were to physical science what the poems of
Homer were to early Greek history. They made men think of the
world as a whole; they carried the mind back into the infinity of
past time; they suggested the first observation of the effects of
fire and water on the earth’s surface. To the ancient physics
they stood much in the same relation which geology does to modern
science. But the Greek was not, like the enquirer of the last
generation, confined to a period of six thousand years; he was
able to speculate freely on the effects of infinite ages in the
production of physical phenomena. He could imagine cities which
had existed time out of mind (States.; Laws), laws or forms of
art and music which had lasted, ‘not in word only, but in very
truth, for ten thousand years’ (Laws); he was aware that natural
phenomena like the Delta of the Nile might have slowly
accumulated in long periods of time (Hdt.). But he seems to have
supposed that the course of events was recurring rather than
progressive. To this he was probably led by the fixedness of
Egyptian customs and the general observation that there were
other civilisations in the world more ancient than that of
Hellas.
The ancient philosophers found in mythology many ideas which, if
not originally derived from nature, were easily transferred to
her—such, for example, as love or hate, corresponding to
attraction or repulsion; or the conception of necessity allied
both to the regularity and irregularity of nature; or of chance,
the nameless or unknown cause; or of justice, symbolizing the law
of compensation; are of the Fates and Furies, typifying the fixed
order or the extraordinary convulsions of nature. Their own
interpretations of Homer and the poets were supposed by them to
be the original meaning. Musing in themselves on the phenomena of
nature, they were relieved at being able to utter the thoughts of
their hearts in figures of speech which to them were not figures,
and were already consecrated by tradition. Hesiod and the Orphic
poets moved in a region of half-personification in which the
meaning or principle appeared through the person. In their vaster
conceptions of Chaos, Erebus, Aether, Night, and the like, the
first rude attempts at generalization are dimly seen. The Gods
themselves, especially the greater Gods, such as Zeus, Poseidon,
Apollo, Athene, are universals as well as individuals. They were
gradually becoming lost in a common conception of mind or God.
They continued to exist for the purposes of ritual or of art; but
from the sixth century onwards or even earlier there arose and
gained strength in the minds of men the notion of ‘one God,
greatest among Gods and men, who was all sight, all hearing, all
knowing’ (Xenophanes).
Under the influence of such ideas, perhaps also deriving from the
traditions of their own or of other nations scraps of medicine
and astronomy, men came to the observation of nature. The Greek
philosopher looked at the blue circle of the heavens and it
flashed upon him that all things were one; the tumult of sense
abated, and the mind found repose in the thought which former
generations had been striving to realize. The first expression of
this was some element, rarefied by degrees into a pure
abstraction, and purged from any tincture of sense. Soon an inner
world of ideas began to be unfolded, more absorbing, more
overpowering, more abiding than the brightest of visible objects,
which to the eye of the philosopher looking inward, seemed to
pale before them, retaining only a faint and precarious
existence. At the same time, the minds of men parted into the two
great divisions of those who saw only a principle of motion, and
of those who saw only a principle of rest, in nature and in
themselves; there were born Heracliteans or Eleatics, as there
have been in later ages born Aristotelians or Platonists. Like
some philosophers in modern times, who are accused of making a
theory first and finding their facts afterwards, the advocates of
either opinion never thought of applying either to themselves or
to their adversaries the criterion of fact. They were mastered by
their ideas and not masters of them. Like the Heraclitean
fanatics whom Plato has ridiculed in the Theaetetus, they were
incapable of giving a reason of the faith that was in them, and
had all the animosities of a religious sect. Yet, doubtless,
there was some first impression derived from external nature,
which, as in mythology, so also in philosophy, worked upon the
minds of the first thinkers. Though incapable of induction or
generalization in the modern sense, they caught an inspiration
from the external world. The most general facts or appearances of
nature, the circle of the universe, the nutritive power of water,
the air which is the breath of life, the destructive force of
fire, the seeming regularity of the greater part of nature and
the irregularity of a remnant, the recurrence of day and night
and of the seasons, the solid earth and the impalpable aether,
were always present to them.
The great source of error and also the beginning of truth to them
was reasoning from analogy; they could see resemblances, but not
differences; and they were incapable of distinguishing
illustration from argument. Analogy in modern times only points
the way, and is immediately verified by experiment. The dreams
and visions, which pass through the philosopher’s mind, of
resemblances between different classes of substances, or between
the animal and vegetable world, are put into the refiner’s fire,
and the dross and other elements which adhere to them are purged
away. But the contemporary of Plato and Socrates was incapable of
resisting the power of any analogy which occurred to him, and was
drawn into any consequences which seemed to follow. He had no
methods of difference or of concomitant variations, by the use of
which he could distinguish the accidental from the essential. He
could not isolate phenomena, and he was helpless against the
influence of any word which had an equivocal or double sense.
Yet without this crude use of analogy the ancient physical
philosopher would have stood still; he could not have made even
‘one guess among many’ without comparison. The course of natural
phenomena would have passed unheeded before his eyes, like fair
sights or musical sounds before the eyes and ears of an animal.
Even the fetichism of the savage is the beginning of reasoning;
the assumption of the most fanciful of causes indicates a higher
mental state than the absence of all enquiry about them. The
tendency to argue from the higher to the lower, from man to the
world, has led to many errors, but has also had an elevating
influence on philosophy. The conception of the world as a whole,
a person, an animal, has been the source of hasty
generalizations; yet this general grasp of nature led also to a
spirit of comprehensiveness in early philosophy, which has not
increased, but rather diminished, as the fields of knowledge have
become more divided. The modern physicist confines himself to one
or perhaps two branches of science. But he comparatively seldom
rises above his own department, and often falls under the
narrowing influence which any single branch, when pursued to the
exclusion of every other, has over the mind. Language, two,
exercised a spell over the beginnings of physical philosophy,
leading to error and sometimes to truth; for many thoughts were
suggested by the double meanings of words (Greek), and the
accidental distinctions of words sometimes led the ancient
philosopher to make corresponding differences in things (Greek).
‘If they are the same, why have they different names; or if they
are different, why have they the same name?’—is an argument not
easily answered in the infancy of knowledge. The modern
philosopher has always been taught the lesson which he still
imperfectly learns, that he must disengage himself from the
influence of words. Nor are there wanting in Plato, who was
himself too often the victim of them, impressive admonitions that
we should regard not words but things (States.). But upon the
whole, the ancients, though not entirely dominated by them, were
much more subject to the influence of words than the moderns.
They had no clear divisions of colours or substances; even the
four elements were undefined; the fields of knowledge were not
parted off. They were bringing order out of disorder, having a
small grain of experience mingled in a confused heap of a priori
notions. And yet, probably, their first impressions, the
illusions and mirages of their fancy, created a greater
intellectual activity and made a nearer approach to the truth
than any patient investigation of isolated facts, for which the
time had not yet come, could have accomplished.
There was one more illusion to which the ancient philosophers
were subject, and against which Plato in his later dialogues
seems to be struggling—the tendency to mere abstractions; not
perceiving that pure abstraction is only negation, they thought
that the greater the abstraction the greater the truth. Behind
any pair of ideas a new idea which comprehended them—the (Greek),
as it was technically termed—began at once to appear. Two are
truer than three, one than two. The words ‘being,’ or ‘unity,’ or
essence,’ or ‘good,’ became sacred to them. They did not see that
they had a word only, and in one sense the most unmeaning of
words. They did not understand that the content of notions is in
inverse proportion to their universality—the element which is the
most widely diffused is also the thinnest; or, in the language of
the common logic, the greater the extension the less the
comprehension. But this vacant idea of a whole without parts, of
a subject without predicates, a rest without motion, has been
also the most fruitful of all ideas. It is the beginning of a
priori thought, and indeed of thinking at all. Men were led to
conceive it, not by a love of hasty generalization, but by a
divine instinct, a dialectical enthusiasm, in which the human
faculties seemed to yearn for enlargement. We know that ‘being’
is only the verb of existence, the copula, the most general
symbol of relation, the first and most meagre of abstractions;
but to some of the ancient philosophers this little word appeared
to attain divine proportions, and to comprehend all truth. Being
or essence, and similar words, represented to them a supreme or
divine being, in which they thought that they found the
containing and continuing principle of the universe. In a few
years the human mind was peopled with abstractions; a new world
was called into existence to give law and order to the old. But
between them there was still a gulf, and no one could pass from
the one to the other.
Number and figure were the greatest instruments of thought which
were possessed by the Greek philosopher; having the same power
over the mind which was exerted by abstract ideas, they were also
capable of practical application. Many curious and, to the early
thinker, mysterious properties of them came to light when they
were compared with one another. They admitted of infinite
multiplication and construction; in Pythagorean triangles or in
proportions of 1:2:4:8 and 1:3:9:27, or compounds of them, the
laws of the world seemed to be more than half revealed. They were
also capable of infinite subdivision—a wonder and also a puzzle
to the ancient thinker (Rep.). They were not, like being or
essence, mere vacant abstractions, but admitted of progress and
growth, while at the same time they confirmed a higher sentiment
of the mind, that there was order in the universe. And so there
began to be a real sympathy between the world within and the
world without. The numbers and figures which were present to the
mind’s eye became visible to the eye of sense; the truth of
nature was mathematics; the other properties of objects seemed to
reappear only in the light of number. Law and morality also found
a natural expression in number and figure. Instruments of such
power and elasticity could not fail to be ‘a most gracious
assistance’ to the first efforts of human intelligence.
There was another reason why numbers had so great an influence
over the minds of early thinkers—they were verified by
experience. Every use of them, even the most trivial, assured men
of their truth; they were everywhere to be found, in the least
things and the greatest alike. One, two, three, counted on the
fingers was a ‘trivial matter (Rep.), a little instrument out of
which to create a world; but from these and by the help of these
all our knowledge of nature has been developed. They were the
measure of all things, and seemed to give law to all things;
nature was rescued from chaos and confusion by their power; the
notes of music, the motions of the stars, the forms of atoms, the
evolution and recurrence of days, months, years, the military
divisions of an army, the civil divisions of a state, seemed to
afford a ‘present witness’ of them—what would have become of man
or of the world if deprived of number (Rep.)? The mystery of
number and the mystery of music were akin. There was a music of
rhythm and of harmonious motion everywhere; and to the real
connexion which existed between music and number, a fanciful or
imaginary relation was superadded. There was a music of the
spheres as well as of the notes of the lyre. If in all things
seen there was number and figure, why should they not also
pervade the unseen world, with which by their wonderful and
unchangeable nature they seemed to hold communion?
Two other points strike us in the use which the ancient
philosophers made of numbers. First, they applied to external
nature the relations of them which they found in their own minds;
and where nature seemed to be at variance with number, as for
example in the case of fractions, they protested against her
(Rep.; Arist. Metaph.). Having long meditated on the properties
of 1:2:4:8, or 1:3:9:27, or of 3, 4, 5, they discovered in them
many curious correspondences and were disposed to find in them
the secret of the universe. Secondly, they applied number and
figure equally to those parts of physics, such as astronomy or
mechanics, in which the modern philosopher expects to find them,
and to those in which he would never think of looking for them,
such as physiology and psychology. For the sciences were not yet
divided, and there was nothing really irrational in arguing that
the same laws which regulated the heavenly bodies were partially
applied to the erring limbs or brain of man. Astrology was the
form which the lively fancy of ancient thinkers almost
necessarily gave to astronomy. The observation that the lower
principle, e.g. mechanics, is always seen in the higher, e.g. in
the phenomena of life, further tended to perplex them. Plato’s
doctrine of the same and the other ruling the courses of the
heavens and of the human body is not a mere vagary, but is a
natural result of the state of knowledge and thought at which he
had arrived.
When in modern times we contemplate the heavens, a certain amount
of scientific truth imperceptibly blends, even with the cursory
glance of an unscientific person. He knows that the earth is
revolving round the sun, and not the sun around the earth. He
does not imagine the earth to be the centre of the universe, and
he has some conception of chemistry and the cognate sciences. A
very different aspect of nature would have been present to the
mind of the early Greek philosopher. He would have beheld the
earth a surface only, not mirrored, however faintly, in the glass
of science, but indissolubly connected with some theory of one,
two, or more elements. He would have seen the world pervaded by
number and figure, animated by a principle of motion, immanent in
a principle of rest. He would have tried to construct the
universe on a quantitative principle, seeming to find in endless
combinations of geometrical figures or in the infinite variety of
their sizes a sufficient account of the multiplicity of
phenomena. To these a priori speculations he would add a rude
conception of matter and his own immediate experience of health
and disease. His cosmos would necessarily be imperfect and
unequal, being the first attempt to impress form and order on the
primaeval chaos of human knowledge. He would see all things as in
a dream.
The ancient physical philosophers have been charged by Dr.
Whewell and others with wasting their fine intelligences in wrong
methods of enquiry; and their progress in moral and political
philosophy has been sometimes contrasted with their supposed
failure in physical investigations. ‘They had plenty of ideas,’
says Dr. Whewell, ‘and plenty of facts; but their ideas did not
accurately represent the facts with which they were acquainted.’
This is a very crude and misleading way of describing ancient
science. It is the mistake of an uneducated person—uneducated,
that is, in the higher sense of the word—who imagines every one
else to be like himself and explains every other age by his own.
No doubt the ancients often fell into strange and fanciful
errors: the time had not yet arrived for the slower and surer
path of the modern inductive philosophy. But it remains to be
shown that they could have done more in their age and country; or
that the contributions which they made to the sciences with which
they were acquainted are not as great upon the whole as those
made by their successors. There is no single step in astronomy as
great as that of the nameless Pythagorean who first conceived the
world to be a body moving round the sun in space: there is no
truer or more comprehensive principle than the application of
mathematics alike to the heavenly bodies, and to the particles of
matter. The ancients had not the instruments which would have
enabled them to correct or verify their anticipations, and their
opportunities of observation were limited. Plato probably did
more for physical science by asserting the supremacy of
mathematics than Aristotle or his disciples by their collections
of facts. When the thinkers of modern times, following Bacon,
undervalue or disparage the speculations of ancient philosophers,
they seem wholly to forget the conditions of the world and of the
human mind, under which they carried on their investigations.
When we accuse them of being under the influence of words, do we
suppose that we are altogether free from this illusion? When we
remark that Greek physics soon became stationary or extinct, may
we not observe also that there have been and may be again periods
in the history of modern philosophy which have been barren and
unproductive? We might as well maintain that Greek art was not
real or great, because it had nihil simile aut secundum, as say
that Greek physics were a failure because they admire no
subsequent progress.
The charge of premature generalization which is often urged
against ancient philosophers is really an anachronism. For they
can hardly be said to have generalized at all. They may be said
more truly to have cleared up and defined by the help of
experience ideas which they already possessed. The beginnings of
thought about nature must always have this character. A true
method is the result of many ages of experiment and observation,
and is ever going on and enlarging with the progress of science
and knowledge. At first men personify nature, then they form
impressions of nature, at last they conceive ‘measure’ or laws of
nature. They pass out of mythology into philosophy. Early science
is not a process of discovery in the modern sense; but rather a
process of correcting by observation, and to a certain extent
only, the first impressions of nature, which mankind, when they
began to think, had received from poetry or language or
unintelligent sense. Of all scientific truths the greatest and
simplest is the uniformity of nature; this was expressed by the
ancients in many ways, as fate, or necessity, or measure, or
limit. Unexpected events, of which the cause was unknown to them,
they attributed to chance (Thucyd.). But their conception of
nature was never that of law interrupted by exceptions,—a
somewhat unfortunate metaphysical invention of modern times,
which is at variance with facts and has failed to satisfy the
requirements of thought.