7. VII
GREEK SCIENCE IN THE EARLY ATTIC PERIOD
WE have travelled rather far in our study of Greek
science, and yet we have not until now come to
Greece itself. And even now, the men whose names
we are to consider were, for the most part, born in out-lying portions of the empire; they differed from the
others we have considered only in the fact that they
were drawn presently to the capital. The change is
due to a most interesting sequence of historical events.
In the day when Thales and his immediate successors
taught in Miletus, when the great men of the
Italic school were in their prime, there was no single
undisputed Centre of Greek influence. The Greeks
were a disorganized company of petty nations, welded
together chiefly by unity of speech; but now, early in
the fifth century B.C., occurred that famous attack upon
the Western world by the Persians under Darius and his
son and successor Xerxes. A few months of battling
determined the fate of the Western world. The Orientals
were hurled back; the glorious memories of Marathon,
Salamis, and Plataea stimulated the patriotism
and enthusiasm of all children of the Greek race. The
Greeks, for the first time, occupied the centre of the
historical stage; for the brief interval of about half a
century the different Grecian principalities lived
together in relative harmony. One city was recognized
as the metropolis of the loosely bound empire; one city
became the home of culture and the Mecca towards
which all eyes turned; that city, of course, was Athens.
For a brief time all roads led to Athens, as, at a later
date, they all led to Rome. The waterways which
alone bound the widely scattered parts of Hellas into
a united whole led out from Athens and back to
Athens, as the spokes of a wheel to its hub. Athens
was the commercial centre, and, largely for that reason,
it became the centre of culture and intellectual influence
also. The wise men from the colonies visited the
metropolis, and the wise Athenians went out to the
colonies. Whoever aspired to become a leader in
politics, in art, in literature, or in philosophy, made his
way to the capital, and so, with almost bewildering
suddenness, there blossomed the civilization of the age
of Pericles; the civilization which produced Æschylus,
Sophocles, Euripides, Herodotus, and Thucydides; the
civilization which made possible the building of the
Parthenon.
ANAXAGORAS
Sometime during the early part of this golden age
there came to Athens a middle-aged man from Clazomenæ,
who, from our present stand-point, was a
more interesting personality than perhaps any other
in the great galaxy of remarkable men assembled there.
The name of this new-comer was Anaxagoras. It was
said in after-time, we know not with what degree of
truth, that he had been a pupil of Anaximenes. If so,
he was a pupil who departed far from the teachings of
his master. What we know for certain is that Anaxagoras
was a truly original thinker, and that he became a
close friend—in a sense the teacher—of Pericles and of
Euripides. Just how long he remained at Athens is not
certain; but the time came when he had made himself
in some way objectionable to the Athenian populace
through his teachings. Filled with the spirit of the
investigator, he could not accept the current conceptions
as to the gods. He was a sceptic, an innovator.
Such men are never welcome; they are the chief factors
in the progress of thought, but they must look always
to posterity for recognition of their worth; from
their contemporaries they receive, not thanks, but
persecution. Sometimes this persecution takes one form,
sometimes another; to the credit of the Greeks be it
said, that with them it usually led to nothing more
severe than banishment. In the case of Anaxagoras,
it is alleged that the sentence pronounced was death;
but that, thanks to the influence of Pericles, this
sentence was commuted to banishment. In any event,
the aged philosopher was sent away from the city of
his adoption. He retired to Lampsacus. "It is not
I that have lost the Athenians,'' he said; "it is the
Athenians that have lost me.''
The exact position which Anaxagoras had among his
contemporaries, and his exact place in the development
of philosophy, have always been somewhat in
dispute. It is not known, of a certainty, that he even
held an open school at Athens. Ritter thinks it doubtful
that he did. It was his fate to be misunderstood,
or underestimated, by Aristotle; that in itself would
have sufficed greatly to dim his fame—might, indeed,
have led to his almost entire neglect had he not been
a truly remarkable thinker. With most of the questions
that have exercised the commentators we have
but scant concern. Following Aristotle, most historians
of philosophy have been metaphysicians; they have
concerned themselves far less with what the ancient
thinkers really knew than with what they thought.
A chance using of a verbal quibble, an esoteric phrase,
the expression of a vague mysticism—these would suffice
to call forth reams of exposition. It has been the
favorite pastime of historians to weave their own anachronistic
theories upon the scanty woof of the half-remembered thoughts of the ancient philosophers.
To make such cloth of the imagination as this is an
alluring pastime, but one that must not divert us here.
Our point of view reverses that of the philosophers.
We are chiefly concerned, not with some vague saying
of Anaxagoras, but with what he really knew regarding
the phenomena of nature; with what he observed,
and with the comprehensible deductions that he derived
from his observations. In attempting to answer
these inquiries, we are obliged, in part, to take our
evidence at second-hand; but, fortunately, some fragments
of writings of Anaxagoras have come down to
us. We are told that he wrote only a single book. It
was said even (by Diogenes) that he was the first man
that ever wrote a work in prose. The latter statement
would not bear too close an examination, yet it is true
that no extensive prose compositions of an earlier day
than this have been preserved, though numerous
others are known by their fragments. Herodotus,
"the father of prose,'' was a slightly younger contemporary
of the Clazomenæan philosopher; not unlikely
the two men may have met at Athens.
Notwithstanding the loss of the greater part of the
writings of Anaxagoras, however, a tolerably precise
account of his scientific doctrines is accessible. Diogenes
Laertius expresses some of them in very clear and
precise terms. We have already pointed out the uncertainty
that attaches to such evidence as this, but it
is as valid for Anaxagoras as for another. If we reject
such evidence, we shall often have almost nothing left;
in accepting it we may at least feel certain that we are
viewing the thinker as his contemporaries and immediate
successors viewed him. Following Diogenes,
then, we shall find some remarkable scientific opinions
ascribed to Anaxagoras. "He asserted,'' we are told,
"that the sun was a mass of burning iron, greater than
Peloponnesus, and that the moon contained houses
and also hills and ravines.'' In corroboration of this,
Plato represents him as having conjectured the right
explanation of the moon's light, and of the solar and
lunar eclipses. He had other astronomical theories
that were more fanciful; thus "he said that the stars
originally moved about in irregular confusion, so that
at first the pole-star, which is continually visible, always
appeared in the zenith, but that afterwards it acquired
a certain declination, and that the Milky Way
was a reflection of the light of the sun when the stars
did not appear. The comets he considered to be a
concourse of planets emitting rays, and the shooting-stars he thought were sparks, as it were, leaping from
the firmament.''
Much of this is far enough from the truth, as we now
know it, yet all of it shows an earnest endeavor to
explain the observed phenomena of the heavens on
rational principles. To have predicated the sun as a
great molten mass of iron was indeed a wonderful
anticipation of the results of the modern spectroscope.
Nor can it be said that this hypothesis of Anaxagoras
was a purely visionary guess. It was in all probability
a scientific deduction from the observed character of
meteoric stones. Reference has already been made
to the alleged prediction of the fall of the famous
meteor at Ægespotomi by Anaxagoras. The assertion
that he actually predicted this fall in any proper sense
of the word would be obviously absurd. Yet the fact
that his name is associated with it suggests that he had
studied similar meteorites, or else that he studied this
particular one, since it is not quite clear whether it
was before or after this fall that he made the famous
assertion that space is full of falling stones. We should
stretch the probabilities were we to assert that Anaxagoras
knew that shooting-stars and meteors were
the same, yet there is an interesting suggestiveness
in his likening the shooting-stars to sparks leaping
from the firmament, taken in connection with his observation
on meteorites. Be this as it may, the fact
that something which falls from heaven as a blazing
light turns out to be an iron-like mass may very well
have suggested to the most rational of thinkers that
the great blazing light called the sun has the same
composition. This idea grasped, it was a not unnatural
extension to conceive the other heavenly bodies
as having the same composition.
This led to a truly startling thought. Since the
heavenly bodies are of the same composition as the
earth, and since they are observed to be whirling
about the earth in space, may we not suppose that they
were once a part of the earth itself, and that they
have been thrown off by the force of a whirling motion?
Such was the conclusion which Anaxagoras
reached; such his explanation of the origin of the
heavenly bodies. It was a marvellous guess. Deduct
from it all that recent science has shown to be untrue;
bear in mind that the stars are suns, compared
with which the earth is a mere speck of dust; recall
that the sun is parent, not daughter, of the earth, and
despite all these deductions, the cosmogonic guess of
Anaxagoras remains, as it seems to us, one of the most
marvellous feats of human intelligence. It was the
first explanation of the cosmic bodies that could be
called, in any sense, an anticipation of what the
science of our own day accepts as a true explanation
of cosmic origins. Moreover, let us urge again that
this was no mere accidental flight of the imagination;
it was a scientific induction based on the only data
available; perhaps it is not too much to say that it was
the only scientific induction which these data would
fairly sustain. Of course it is not for a moment to be
inferred that Anaxagoras understood, in the modern
sense, the character of that whirling force which we
call centrifugal. About two thousand years were yet
to elapse before that force was explained as elementary
inertia; and even that explanation, let us not forget,
merely sufficed to push back the barriers of mystery
by one other stage; for even in our day inertia is a
statement of fact rather than an explanation.
But however little Anaxagoras could explain the
centrifugal force on mechanical principles, the
practical powers of that force were sufficiently open to his
observation. The mere experiment of throwing a
stone from a sling would, to an observing mind, be
full of suggestiveness. It would be obvious that by
whirling the sling about, the stone which it held would
be sustained in its circling path about the hand in
seeming defiance of the earth's pull, and after the stone
had left the sling, it could fly away from the earth to
a distance which the most casual observation would
prove to be proportionate to the speed of its flight.
Extremely rapid motion, then, might project bodies
from the earth's surface off into space; a sufficiently
rapid whirl would keep them there. Anaxagoras
conceived that this was precisely what had occurred.
His imagination even carried him a step farther—to a
conception of a slackening of speed, through which the
heavenly bodies would lose their centrifugal force,
and, responding to the perpetual pull of gravitation,
would fall back to the earth, just as the great stone at
Ægespotomi had been observed to do.
Here we would seem to have a clear conception of
the idea of universal gravitation, and Anaxagoras
stands before us as the anticipator of Newton. Were
it not for one scientific maxim, we might exalt the old
Greek above the greatest of modern natural philosophers;
but that maxim bids us pause. It is phrased
thus, "He discovers who proves.'' Anaxagoras could
not prove; his argument was at best suggestive, not
demonstrative. He did not even know the laws
which govern falling bodies; much less could he apply
such laws, even had he known them, to sidereal bodies
at whose size and distance he could only guess in the
vaguest terms. Still his cosmogonic speculation remains
as perhaps the most remarkable one of antiquity.
How widely his speculation found currency
among his immediate successors is instanced in a
passage from Plato, where Socrates is represented as
scornfully answering a calumniator in these terms:
"He asserts that I say the sun is a stone and the
moon an earth. Do you think of accusing Anaxagoras,
Miletas, and have you so low an opinion of these
men, and think them so unskilled in laws, as not to
know that the books of Anaxagoras the Clazomenæan
are full of these doctrines. And forsooth the young
men are learning these matters from me which sometimes
they can buy from the orchestra for a drachma,
at the most, and laugh at Socrates if he pretends they
are his-particularly seeing they are so strange.''
The element of error contained in these cosmogonic
speculations of Anaxagoras has led critics to do them
something less than justice. But there is one other
astronomical speculation for which the Clazomenæan
philosopher has received full credit. It is generally
admitted that it was he who first found out the explanation
of the phases of the moon; a knowledge that
that body shines only by reflected light, and that its
visible forms, waxing and waning month by month
from crescent to disk and from disk to crescent, merely
represent our shifting view of its sun-illumined face.
It is difficult to put ourselves in the place of the ancient
observer and realize how little the appearances
suggest the actual fact. That a body of the same
structure as the earth should shine with the radiance
of the moon merely because sunlight is reflected from
it, is in itself a supposition seemingly contradicted by
ordinary experience. It required the mind of a philosopher,
sustained, perhaps, by some experimental observations,
to conceive the idea that what seems so
obviously bright may be in reality dark. The germ
of the conception of what the philosopher speaks of
as the noumena, or actualities, back of phenomena
or appearances, had perhaps this crude beginning.
Anaxagoras could surely point to the moon in support
of his seeming paradox that snow, being really composed
of water, which is dark, is in reality black and
not white—a contention to which we shall refer more
at length in a moment.
But there is yet another striking thought connected
with this new explanation of the phases of the moon.
The explanation implies not merely the reflection of
light by a dark body, but by a dark body of a particular
form. Granted that reflections are in question,
no body but a spherical one could give an appearance
which the moon presents. The moon, then, is
not merely a mass of earth, it is a spherical mass
of earth. Here there were no flaws in the reasoning
of Anaxagoras. By scientific induction he passed
from observation to explanation. A new and most
important element was added to the science of astronomy.
Looking back from the latter-day stand-point, it
would seem as if the mind of the philosopher must
have taken one other step: the mind that had conceived
sun, moon, stars, and earth to be of one substance
might naturally, we should think, have reached
out to the further induction that, since the moon is a
sphere, the other cosmic bodies, including the earth,
must be spheres also. But generalizer as he was, Anaxagoras
was too rigidly scientific a thinker to make
this assumption. The data at his command did not,
as he analyzed them, seem to point to this conclusion.
We have seen that Pythagoras probably, and Parmenides
surely, out there in Italy had conceived the
idea of the earth's rotundity, but the Pythagorean
doctrines were not rapidly taken up in the mother-country, and Parmenides, it must be recalled, was a
strict contemporary of Anaxagoras himself. It is no
reproach, therefore, to the Clazomenæan philosopher
that he should have held to the old idea that the
earth is flat, or at most a convex disk—the latter being
the Babylonian conception which probably dominated
that Milesian school to which Anaxagoras harked
back.
Anaxagoras may never have seen an eclipse of the
moon, and even if he had he might have reflected that,
from certain directions, a disk may throw precisely the
same shadow as a sphere. Moreover, in reference to
the shadow cast by the earth, there was, so Anaxagoras
believed, an observation open to him nightly which,
we may well suppose, was not without influence in
suggesting to his mind the probable shape of the earth.
The Milky Way, which doubtless had puzzled astronomers
from the beginnings of history and which was
to continue to puzzle them for many centuries after
the day of Anaxagoras, was explained by the Clazomenæan
philosopher on a theory obviously suggested
by the theory of the moon's phases. Since the earth-like moon shines by reflected light at night, and
since the stars seem obviously brighter on dark nights,
Anaxagoras was but following up a perfectly logical
induction when he propounded the theory that the
stars in the Milky Way seem more numerous and
brighter than those of any other part of the heavens,
merely because the Milky Way marks the shadow of
the earth. Of course the inference was wrong, so far
as the shadow of the earth is concerned; yet it contained
a part truth, the force of which was never fully recognized
until the time of Galileo. This consists in the
assertion that the brightness of the Milky Way is
merely due to the glow of many stars. The shadow-theory of Anaxagoras would naturally cease to have
validity so soon as the sphericity of the earth was
proved, and with it, seemingly, fell for the time the
companion theory that the Milky Way is made up of
a multitude of stars.
It has been said by a modern critic [62]
that the shadow-theory was childish in that it failed to note
that the Milky Way does not follow the course of the
ecliptic. But this criticism only holds good so long
as we reflect on the true character of the earth as a
symmetrical body poised in space. It is quite possible
to conceive a body occupying the position of the
earth with reference to the sun which would cast a
shadow having such a tenuous form as the Milky Way
presents. Such a body obviously would not be a
globe, but a long-drawn-out, attenuated figure. There
is, to be sure, no direct evidence preserved to show that
Anaxagoras conceived the world to present such a
figure as this, but what we know of that philosopher's
close-reasoning, logical mind gives some warrant to
the assumption—gratuitous though in a sense it be—
that the author of the theory of the moon's phases had
not failed to ask himself what must be the form of that
terrestrial body which could cast the tenuous shadow
of the Milky Way. Moreover, we must recall that the
habitable earth, as known to the Greeks of that day,
was a relatively narrow band of territory, stretching
far to the east and to the west.
Anaxagoras as Meteorologist
The man who had studied the meteorite of Ægospotami,
and been put by it on the track of such remarkable
inductions, was, naturally, not oblivious to
the other phenomena of the atmosphere. Indeed, such
a mind as that of Anaxagoras was sure to investigate
all manner of natural phenomena, and almost
equally sure to throw new light on any subject that it
investigated. Hence it is not surprising to find Anaxagoras
credited with explaining the winds as due to the
rarefactions of the atmosphere produced by the sun.
This explanation gives Anaxagoras full right to be
called "the father of meteorology,'' a title which, it
may be, no one has thought of applying to him, chiefly
because the science of meteorology did not make its
real beginnings until some twenty-four hundred years
after the death of its first great votary. Not content
with explaining the winds, this prototype of Franklin
turned his attention even to the tipper atmosphere.
"Thunder,'' he is reputed to have said, "was produced
by the collision of the clouds, and lightning by the rubbing
together of the clouds.'' We dare not go so far
as to suggest that this implies an association in the
mind of Anaxagoras between the friction of the clouds
and the observed electrical effects generated by the
friction of such a substance as amber. To make such
a suggestion doubtless would be to fall victim to the
old familiar propensity to read into Homer things that
Homer never knew. Yet the significant fact remains
that Anaxagoras ascribed to thunder and to lightning
their true position as strictly natural phenomena.
For him it was no god that menaced humanity with
thundering voice and the flash of his divine fires from
the clouds. Little wonder that the thinker whose
science carried him to such scepticism as this should
have felt the wrath of the superstitious Athenians.
Biological Speculations
Passing from the phenomena of the air to those of
the earth itself, we learn that Anaxagoras explained an
earthquake as being produced by the returning of air
into the earth. We cannot be sure as to the exact
meaning here, though the idea that gases are imprisoned
in the substance of the earth seems not far
afield. But a far more remarkable insight than this
would imply was shown by Anaxagoras when he asserted
that a certain amount of air is contained in
water, and that fishes breathe this air. The passage
of Aristotle in which this opinion is ascribed to
Anaxagoras is of sufficient interest to be quoted at
length:
"Democritus, of Abdera,'' says Aristotle, "and some
others, that have spoken concerning respiration, have
determined nothing concerning other animals, but
seem to have supposed that all animals respire. But
Anaxagoras and Diogenes (Apolloniates), who say that
all animals respire, have also endeavored to explain
how fishes, and all those animals that have a hard,
rough shell, such as oysters, mussels, etc., respire.
And Anaxagoras, indeed, says that fishes, when they
emit water through their gills, attract air from the
mouth to the vacuum in the viscera from the water
which surrounds the mouth; as if air was inherent in
the water.''
[63]
It should be recalled that of the three philosophers
thus mentioned as contending that all animals respire,
Anaxagoras was the elder; he, therefore, was
presumably the originator of the idea. It will be
observed, too, that Anaxagoras alone is held responsible
for the idea that fishes respire air through their
gills, "attracting'' it from the water. This certainly
was one of the shrewdest physiological guesses of
any age, if it be regarded as a mere guess. With
greater justice we might refer to it as a profound
deduction from the principle of the uniformity of
nature.
In making such a deduction, Anaxagoras was far in
advance of his time as illustrated by the fact that
Aristotle makes the citation we have just quoted
merely to add that "such things are impossible,'' and
to refute these "impossible'' ideas by means of
metaphysical reasonings that seemed demonstrative not
merely to himself, but to many generations of his followers.
We are told that Anaxagoras alleged that all animals
were originally generated out of moisture, heat, and
earth particles. Just what opinion he held concerning
man's development we are not informed. Yet there is
one of his phrases which suggests—without, perhaps,
quite proving—that he was an evolutionist. This
phrase asserts, with insight that is fairly startling,
that man is the most intelligent of animals because he
has hands. The man who could make that assertion
must, it would seem, have had in mind the idea of the
development of intelligence through the use of hands—
an idea the full force of which was not evident to
subsequent generations of thinkers until the time of
Darwin.
Physical Speculations
Anaxagoras is cited by Aristotle as believing that
"plants are animals and feel pleasure and pain, inferring
this because they shed their leaves and let
them grow again.'' The idea is fanciful, yet it suggests
again a truly philosophical conception of the unity of
nature. The man who could conceive that idea was
but little hampered by traditional conceptions. He
was exercising a rare combination of the rigidly scientific
spirit with the poetical imagination. He who
possesses these gifts is sure not to stop in his questionings
of nature until he has found some thinkable
explanation of the character of matter itself. Anaxagoras
found such an explanation, and, as good luck
would have it, that explanation has been preserved.
Let us examine his reasoning in some detail. We
have already referred to the claim alleged to have been
made by Anaxagoras that snow is not really white,
but black. The philosopher explained his paradox,
we are told, by asserting that snow is really water,
and that water is dark, when viewed under proper
conditions—as at the bottom of a well. That idea
contains the germ of the Clazomenæan philosopher's
conception of the nature of matter. Indeed, it is not
unlikely that this theory of matter grew out of his
observation of the changing forms of water. He seems
clearly to have grasped the idea that snow on the one
hand, and vapor on the other, are of the same intimate
substance as the water from which they are
derived and into which they may be again transformed.
The fact that steam and snow can be changed back
into water, and by simple manipulation cannot be
changed into any other substance, finds, as we now believe,
its true explanation in the fact that the molecular
structure, as we phrase it—that is to say, the ultimate
particle of which water is composed, is not changed,
and this is precisely the explanation which Anaxagoras
gave of the same phenomena. For him the unit particle
of water constituted an elementary body, uncreated,
unchangeable, indestructible. This particle,
in association with like particles, constitutes the
substance which we call water. The same particle in
association with particles unlike itself, might produce
totally different substances—as, for example, when
water is taken up by the roots of a plant and becomes,
seemingly, a part of the substance of the plant. But
whatever the changed association, so Anaxagoras
reasoned, the ultimate particle of water remains a particle
of water still. And what was true of water was
true also, so he conceived, of every other substance.
Gold, silver, iron, earth, and the various vegetables
and animal tissues—in short, each and every one of
all the different substances with which experience
makes us familiar, is made up of unit particles which
maintain their integrity in whatever combination
they may be associated. This implies, obviously, a
multitude of primordial particles, each one having an
individuality of its own; each one, like the particle of
water already cited, uncreated, unchangeable, and
indestructible.
Fortunately, we have the philosopher's own words
to guide us as to his speculations here. The fragments
of his writings that have come down to us
(chiefly through the quotations of Simplicius) deal
almost exclusively with these ultimate conceptions of
his imagination. In ascribing to him, then, this conception
of diverse, uncreated, primordial elements,
which can never be changed, but can only be mixed
together to form substances of the material world,
we are not reading back post-Daltonian knowledge
into the system of Anaxagoras. Here are his words:
"The Greeks do not rightly use the terms `coming
into being' and `perishing.' For nothing comes into
being, nor, yet, does anything perish; but there is
mixture and separation of things that are. So they
would do right in calling `coming into being' `mixture'
and `perishing' `separation.' For how could hair
come from what is not hair? Or flesh from what is
not flesh?''
Elsewhere he tells us that (at one stage of the world's
development) "the dense, the moist, the cold, the dark,
collected there where now is earth; the rare, the warm,
the dry, the bright, departed towards the further part
of the æther. The earth is condensed out of these
things that are separated, for water is separated from
the clouds, and earth from the water; and from the
earth stones are condensed by the cold, and these are
separated farther from the water.'' Here again the
influence of heat and cold in determining physical
qualities is kept pre-eminently in mind. The dense,
the moist, the cold, the dark are contrasted with the
rare, the warm, the dry, and bright; and the formation
of stones is spoken of as a specific condensation due to
the influence of cold. Here, then, we have nearly all
the elements of the Daltonian theory of atoms on the
one hand, and the nebular hypothesis of Laplace on
the other. But this is not quite all. In addition to
such diverse elementary particles as those of gold,
water, and the rest, Anaxagoras conceived a species
of particles differing from all the others, not merely
as they differ from one another, but constituting a
class by themselves; particles infinitely smaller than
the others; particles that are described as infinite,
self-powerful, mixed with nothing, but existing alone.
That is to say (interpreting the theory in the only
way that seems plausible), these most minute particles
do not mix with the other primordial particles
to form material substances in the same way in which
these mixed with one another. But, on the other
hand, these "infinite, self-powerful, and unmixed''
particles commingle everywhere and in every substance
whatever with the mixed particles that go to
make up the substances.
There is a distinction here, it will be observed,
which at once suggests the modern distinction between
physical processes and chemical processes, or, putting
it otherwise, between molecular processes and atomic
processes; but the reader must be guarded against
supposing that Anaxagoras had any such thought as this
in mind. His ultimate mixable particles can be compared
only with the Daltonian atom, not with the molecule
of the modern physicist, and his "infinite, self-powerful, and unmixable'' particles are not comparable
with anything but the ether of the modern physicist,
with which hypothetical substance they have many
points of resemblance. But the "infinite, self-powerful, and unmixed'' particles constituting thus an
ether-like plenum which permeates all material structures,
have also, in the mind of Anaxagoras, a function
which carries them perhaps a stage beyond the province
of the modern ether. For these "infinite, self
powerful, and unmixed'' particles are imbued with,
and, indeed, themselves constitute, what Anaxagoras
terms
nous, a word which the modern translator has
usually paraphrased as "mind.'' Neither that word
nor any other available one probably conveys an
accurate idea of what Anaxagoras meant to imply by the
word
nous. For him the word meant not merely
"mind'' in the sense of receptive and comprehending
intelligence, but directive and creative intelligence
as well. Again let Anaxagoras speak for himself:
"Other things include a portion of everything, but
nous is infinite, and self-powerful, and mixed with
nothing, but it exists alone, itself by itself. For if it
were not by itself, but were mixed with anything else,
it would include parts of all things, if it were mixed with
anything; for a portion of everything exists in every
thing, as has been said by me before, and things
mingled with it would prevent it from having power
over anything in the same way that it does now that it
is alone by itself. For it is the most rarefied of all
things and the purest, and it has all knowledge in regard
to everything and the greatest power; over all
that has life, both greater and less,
nous rules. And
nous ruled the rotation of the whole, so that it set it in
rotation in the beginning. First it began the rotation
from a small beginning, then more and more was included
in the motion, and yet more will be included.
Both the mixed and the separated and distinct, all
things
nous recognized. And whatever things were
to be, and whatever things were, as many as are now,
and whatever things shall be, all these
nous arranged
in order; and it arranged that rotation, according to
which now rotate stars and sun and moon and air and
æther, now that they are separated. Rotation itself
caused the separation, and the dense is separated from
the rare, the warm from the cold, the bright from the
dark, the dry from the moist. And when
nous began
to set things in motion, there was separation from
everything that was in motion, all this was made distinct.
The rotation of the things that were moved
and made distinct caused them to be yet more distinct.''
[64]
Nous, then, as Anaxagoras conceives it, is "the most
rarefied of all things, and the purest, and it has knowledge
in regard to everything and the greatest power;
over all that has life, both greater and less, it rules.''
But these are postulants of omnipresence and omniscience.
In other words, nous is nothing less than
the omnipotent artificer of the material universe. It
lacks nothing of the power of deity, save only that we
are not assured that it created the primordial particles.
The creation of these particles was a conception that
for Anaxagoras, as for the modern Spencer, lay beyond
the range of imagination.
Nous is the artificer, working
with "uncreated'' particles. Back of
nous and
the particles lies, for an Anaxagoras as for a Spencer,
the Unknowable. But
nous itself is the equivalent of
that universal energy of motion which science recognizes
as operating between the particles of matter, and
which the theologist personifies as Deity. It is
Pantheistic deity as Anaxagoras conceives it; his may be
called the first scientific conception of a non-anthropomorphic god. In elaborating this conception
Anaxagoras proved himself one of the most remarkable
scientific dreamers of antiquity. To have substituted for
the Greek Pantheon of anthropomorphic deities the
conception of a non-anthropomorphic immaterial and
ethereal entity, of all things in the world "the most
rarefied and the purest,'' is to have performed a feat
which, considering the age and the environment in
which it was accomplished, staggers the imagination.
As a strictly scientific accomplishment the great thinker's
conception of primordial elements contained a
germ of the truth which was to lie dormant for 2200
years, but which then, as modified and vitalized by
the genius of Dalton, was to dominate the new chemical
science of the nineteenth century. If there are
intimations that the primordial element of Anaxagoras
and of Dalton may turn out in the near future to be
itself a compound, there will still remain the yet finer
particles of the
nous of Anaxagoras to baffle the most
subtle analysis of which to-day's science gives us any
pre-vision. All in all, then, the work of Anaxagoras
must stand as that of perhaps the most far-seeing
scientific imagination of pre-Socratic antiquity.
LEUCIPPUS AND DEMOCRITUS
But we must not leave this alluring field of speculation
as to the nature of matter without referring to
another scientific guess, which soon followed that of
Anaxagoras and was destined to gain even wider fame,
and which in modern times has been somewhat unjustly
held to eclipse the glory of the other achievement.
We mean, of course, the atomic theory of
Leucippus and Democritus. This theory reduced all
matter to primordial elements, called atoms
ατομα
because they are by hypothesis incapable of further
division. These atoms, making up the entire material
universe, are in this theory conceived as qualitatively
identical, differing from one another only
in size and perhaps in shape. The union of different-sized
atoms in endless combinations produces the
diverse substances with which our senses make us
familiar.
Before we pass to a consideration of this alluring
theory, and particularly to a comparison of it with
the theory of Anaxagoras, we must catch a glimpse
of the personality of the men to whom the theory
owes its origin. One of these, Leucippus, presents
so uncertain a figure as to be almost mythical. Indeed,
it was long questioned whether such a man
had actually lived, or whether be were not really an
invention of his alleged disciple, Democritus. Latter-
day scholarship, however, accepts him as a real
personage, though knowing scarcely more of him than
that he was the author of the famous theory with
which his name was associated. It is suggested that
he was a wanderer, like most philosophers of his
time, and that later in life he came to Abdera, in
Thrace, and through this circumstance became the
teacher of Democritus. This fable answers as well
as another. What we really know is that Democritus
himself, through whose writings and teachings
the atomic theory gained vogue, was born in Abdera,
about the year 460 B.C.—that is to say, just about
the time when his great precursor, Anaxagoras, was
migrating to Athens. Democritus, like most others
of the early Greek thinkers, lives in tradition as a picturesque
figure. It is vaguely reported that he travelled
for a time, perhaps in the East and in Egypt, and
that then he settled down to spend the remainder of his
life in Abdera. Whether or not he visited Athens in
the course of his wanderings we do not know. At
Abdera he was revered as a sage, but his influence upon
the practical civilization of the time was not marked.
He was pre-eminently a dreamer and a writer. Like
his confrères of the epoch, he entered all fields of
thought. He wrote voluminously, but, unfortunately,
his writings have, for the most part, perished. The
fables and traditions of a later day asserted that
Democritus had voluntarily put out his own eyes that he
might turn his thoughts inward with more concentration.
Doubtless this is fiction, yet, as usual with
such fictions, it contains a germ of truth; for we may
well suppose that the promulgator of the atomic
theory was a man whose mind was attracted by the
subtleties of thought rather than by the tangibilities
of observation. Yet the term "laughing philosopher,''
which seems to have been universally applied to
Democritus, suggests a mind not altogether withdrawn
from the world of practicalities.
So much for Democritus the man. Let us return
now to his theory of atoms. This theory, it must be
confessed, made no very great impression upon his
contemporaries. It found an expositor, a little later,
in the philosopher Epicurus, and later still the poet
Lucretius gave it popular expression. But it seemed
scarcely more than the dream of a philosopher or the
vagary of a poet until the day when modern science
began to penetrate the mysteries of matter. When,
finally, the researches of Dalton and his followers had
placed the atomic theory on a surer footing as the foundation
of modern chemistry, the ideas of the old laughing
philosopher of Abdera, which all along had been half
derisively remembered, were recalled with a new interest.
Now it appeared that these ideas had curiously
foreshadowed nineteenth-century knowledge. It appeared
that away back in the fifth century B.C. a man
had dreamed out a conception of the ultimate nature
of matter which had waited all these centuries for
corroboration. And now the historians of philosophy became
more than anxious to do justice to the memory
of Democritus.
It is possible that this effort at poetical restitution
has carried the enthusiast too far. There is, indeed, a
curious suggestiveness in the theory of Democritus;
there is philosophical allurement in his reduction of all
matter to a single element; it contains, it may be, not
merely a germ of the science of the nineteenth-century
chemistry, but perhaps the germs also of the yet
undeveloped chemistry of the twentieth century. Yet
we dare suggest that in their enthusiasm for the atomic
theory of Democritus the historians of our generation
have done something less than justice to that
philosopher's precursor, Anaxagoras. And one suspects
that the mere accident of a name has been
instrumental in producing this result. Democritus
called his primordial element an atom; Anaxagoras,
too, conceived a primordial element, but he called it
merely a seed or thing; he failed to christen it
distinctively. Modern science adopted the word atom and
gave it universal vogue. It owed a debt of gratitude
to Democritus for supplying it the word, but it somewhat
overpaid the debt in too closely linking the new
meaning of the word with its old original one. For,
let it be clearly understood, the Daltonian atom is not
precisely comparable with the atom of Democritus.
The atom, as Democritus conceived it, was monistic;
all atoms, according to this hypothesis, are of
the same substance; one atom differs from another
merely in size and shape, but not at all in quality.
But the Daltonian hypothesis conceived, and nearly
all the experimental efforts of the nineteenth century
seemed to prove, that there are numerous classes of
atoms, each differing in its very essence from the
others.
As the case stands to-day the chemist deals with
seventy-odd substances, which he calls elements.
Each one of these substances is, as he conceives it,
made up of elementary atoms having a unique personality,
each differing in quality from all the others.
As far as experiment has thus far safely carried us, the
atom of gold is a primordial element which remains an
atom of gold and nothing else, no matter with what
other atoms it is associated. So, too, of the atom
of silver, or zinc, or sodium—in short, of each and
every one of the seventy-odd elements. There are, indeed,
as we shall see, experiments that suggest the
dissolution of the atom—that suggest, in short, that the
Daltonian atom is misnamed, being a structure that
may, under certain conditions, be broken asunder.
But these experiments have, as yet, the warrant rather
of philosophy than of pure science, and to-day we demand
that the philosophy of science shall be the handmaid
of experiment.
When experiment shall have demonstrated that the
Daltonian atom is a compound, and that in truth there
is but a single true atom, which, combining with its
fellows perhaps in varying numbers and in different
special relations, produces the Daltonian atoms, then
the philosophical theory of monism will have the experimental
warrant which to-day it lacks; then we shall be
a step nearer to the atom of Democritus in one direction,
a step farther away in the other. We shall be
nearer, in that the conception of Democritus was, in a
sense, monistic; farther away, in that all the atoms of
Democritus, large and small alike, were considered as
permanently fixed in size. Democritus postulated
all his atoms as of the same substance, differing not at
all in quality; yet he was obliged to conceive that the
varying size of the atoms gave to them varying functions
which amounted to qualitative differences. He
might claim for his largest atom the same quality of
substance as for his smallest, but so long as he conceived
that the large atoms, when adjusted together to
form a tangible substance, formed a substance different
in quality from the substance which the small
atoms would make up when similarly grouped, this
concession amounts to the predication of difference of
quality between the atoms themselves. The entire
question reduces itself virtually to a quibble over the
word quality, So long as one atom conceived to be
primordial and indivisible is conceded to be of such
a nature as necessarily to produce a different impression
on our senses, when grouped with its fellows,
from the impression produced by other atoms when
similarly grouped, such primordial atoms do differ
among themselves in precisely the same way for all
practical purposes as do the primordial elements of
Anaxagoras.
The monistic conception towards which twentieth-century chemistry seems to be carrying us may perhaps
show that all the so-called atoms are compounded
of a single element. All the true atoms making up that
element may then properly be said to have the same
quality, but none the less will it remain true that the
combinations of that element that go to make up the
different Daltonian atoms differ from one another in
quality in precisely the same sense in which such tangible
substances as gold, and oxygen, and mercury, and
diamonds differ from one another. In the last analysis
of the monistic philosophy, there is but one substance
and one quality in the universe. In the widest view
of that philosophy, gold and oxygen and mercury and
diamonds are one substance, and, if you please, one
quality. But such refinements of analysis as this are
for the transcendental philosopher, and not for the
scientist. Whatever the allurement of such reasoning,
we must for the purpose of science let words have a
specific meaning, nor must we let a mere word-jugglery
blind us to the evidence of facts. That was the rock
on which Greek science foundered; it is the rock which
the modern helmsman sometimes finds it difficult to
avoid. And if we mistake not, this case of the atom of
Democritus is precisely a case in point. Because Democritus
said that his atoms did not differ in quality,
the modern philosopher has seen in his theory the essentials
of monism; has discovered in it not merely a
forecast of the chemistry of the nineteenth century,
but a forecast of the hypothetical chemistry of the
future. And, on the other hand, because Anaxagoras
predicted a different quality for his primordial elements,
the philosopher of our day has discredited the
primordial element of Anaxagoras.
Yet if our analysis does not lead us astray, the
theory of Democritus was not truly monistic; his indestructible
atoms, differing from one another in size
and shape, utterly incapable of being changed from
the form which they had maintained from the beginning,
were in reality as truly and primordially different
as are the primordial elements of Anaxagoras.
In other words, the atom of Democritus is nothing less
than the primordial seed of Anaxagoras, a little more
tangibly visualized and given a distinctive name.
Anaxagoras explicitly conceived his elements as
invisibly small, as infinite in number, and as made up of
an indefinite number of kinds—one for each distinctive
substance in the world. But precisely the same postulates
are made of the atom of Democritus. These
also are invisibly small; these also are infinite in number;
these also are made up of an indefinite number
of kinds, corresponding with the observed difference
of substances in the world. "Primitive seeds,'' or
"atoms,'' were alike conceived to be primordial,
unchangeable, and indestructible. Wherein then lies the
difference? We answer, chiefly in a name; almost
solely in the fact that Anaxagoras did not attempt to
postulate the physical properties of the elements beyond
stating that each has a distinctive personality,
while Democritus did attempt to postulate these properties.
He, too, admitted that each kind of element
has its distinctive personality, and he attempted to
visualize and describe the characteristics of the personality.
Thus while Anaxagoras tells us nothing of his elements
except that they differ from one another, Democritus
postulates a difference in size, imagines some
elements as heavier and some as lighter, and conceives
even that the elements may be provided with projecting
hooks, with the aid of which they link themselves
one with another. No one to-day takes these crude
visualizings seriously as to their details. The sole element
of truth which these dreamings contain, as distinguishing
them from the dreamings of Anaxagoras,
is in the conception that the various atoms differ
in size and weight. Here, indeed, is a vague fore-shadowing of that chemistry of form which began
to come into prominence towards the close of the
nineteenth century. To have forecast even dimly this
newest phase of chemical knowledge, across the abyss
of centuries, is indeed a feat to put Democritus in
the front rank of thinkers. But this estimate should
not blind us to the fact that the pre-vision of
Democritus was but a slight elaboration of a theory
which had its origin with another thinker. The association
between Anaxagoras and Democritus cannot
be directly traced, but it is an association which the
historian of ideas should never for a moment forget.
If we are not to be misled by mere word-jugglery, we
shall recognize the founder of the atomic theory of
matter in Anaxagoras; its expositors along slightly
different lines in Leucippus and Democritus; its re-discoverer of the nineteenth century in Dalton. All
in all, then, just as Anaxagoras preceded Democritus
in time, so must he take precedence over him also as
an inductive thinker, who carried the use of the scientific
imagination to its farthest reach.
An analysis of the theories of the two men leads to
somewhat the same conclusion that might be reached
from a comparison of their lives. Anaxagoras was a
sceptical, experimental scientist, gifted also with the
prophetic imagination. He reasoned always from the
particular to the general, after the manner of true induction,
and he scarcely took a step beyond the confines
of secure induction. True scientist that he was,
he could content himself with postulating different
qualities for his elements, without pretending to know
how these qualities could be defined. His elements
were by hypothesis invisible, hence he would not
attempt to visualize them. Democritus, on the other
hand, refused to recognize this barrier. Where he
could not know, he still did not hesitate to guess.
Just as he conceived his atom of a definite form with a
definite structure, even so he conceived that the atmosphere
about him was full of invisible spirits; he
accepted the current superstitions of his time. Like
the average Greeks of his day, he even believed in such
omens as those furnished by inspecting the entrails of a
fowl. These chance bits of biography are weather-vanes of the mind of Democritus. They tend to
substantiate our conviction that Democritus must rank
below Anaxagoras as a devotee of pure science. But,
after all, such comparisons and estimates as this are
utterly futile. The essential fact for us is that here,
in the fifth century before our era, we find put forward
the most penetrating guess as to the constitution of
matter that the history of ancient thought has to present
to us. In one direction, the avenue of progress
is barred; there will be no farther step that way till
we come down the centuries to the time of Dalton.
HIPPOCRATES AND GREEK MEDICINE
These studies of the constitution of matter have carried
us to the limits of the field of scientific imagination
in antiquity; let us now turn sharply and consider a
department of science in which theory joins hands with
practicality. Let us witness the beginnings of scientific
therapeutics.
Medicine among the early Greeks, before the time
of Hippocrates, was a crude mixture of religion, necromancy,
and mysticism. Temples were erected to
the god of medicine, Æsculapius, and sick persons
made their way, or were carried, to these temples, where
they sought to gain the favor of the god by suitable
offerings, and learn the way to regain their health
through remedies or methods revealed to them in
dreams by the god. When the patient had been thus
cured, he placed a tablet in the temple describing his
sickness, and telling by what method the god had cured
him. He again made suitable offerings at the temple,
which were sometimes in the form of gold or silver
representations of the diseased organ—a gold or silver
model of a heart, hand, foot, etc.
Nevertheless, despite this belief in the supernatural,
many drugs and healing lotions were employed, and
the Greek physicians possessed considerable skill in
dressing wounds and bandaging. But they did not
depend upon these surgical dressings alone, using with
them certain appropriate prayers and incantations,
recited over the injured member at the time of applying
the dressings.
Even the very early Greeks had learned something of
anatomy. The daily contact with wounds and broken
bones must of necessity lead to a crude understanding
of anatomy in general. The first Greek anatomist,
however, who is recognized as such, is said to have been
Alcmæon. He is said to have made extensive dissections
of the lower animals, and to have described
many hitherto unknown structures, such as the optic
nerve and the Eustachian canal—the small tube leading
into the throat from the ear. He is credited with
many unique explanations of natural phenomena, such
as, for example, the explanation that "hearing is
produced by the hollow bone behind the ear; for all hollow
things are sonorous.'' He was a rationalist, and he
taught that the brain is the organ of mind. The
sources of our information about his work, however,
are unreliable.
Democedes, who lived in the sixth century B.C., is
the first physician of whom we have any trustworthy
history. We learn from Herodotus that he came from
Croton to Ægina, where, in recognition of his skill, he
was appointed medical officer of the city. From
Ægina he was called to Athens at an increased salary,
and later was in charge of medical affairs in several
other Greek cities. He was finally called to Samos by
the tyrant Polycrates, who reigned there from about
536 to 522 B.C. But on the death of Polycrates, who
was murdered by the Persians, Democedes became a
slave. His fame as a physician, however, had reached
the ears of the Persian monarch, and shortly after his
capture he was permitted to show his skill upon King
Darius himself. The Persian monarch was suffering
from a sprained ankle, which his Egyptian surgeons
had been unable to cure. Democedes not only cured
the injured member but used his influence in saving
the lives of his Egyptian rivals, who had been condemned
to death by the king.
At another time he showed his skill by curing the
queen, who was suffering from a chronic abscess of long
standing. This so pleased the monarch that he offered
him as a reward anything he might desire, except his
liberty. But the costly gifts of Darius did not satisfy
him so long as he remained a slave; and determined to
secure his freedom at any cost, he volunteered to lead
some Persian spies into his native country, promising
to use his influence in converting some of the leading
men of his nation to the Persian cause. Laden with
the wealth that had been heaped upon him by Darius,
he set forth upon his mission, but upon reaching his
native city of Croton he threw off his mask, renounced
his Persian mission, and became once more a free
Greek.
While the story of Democedes throws little light
upon the medical practices of the time, it shows that
paid city medical officers existed in Greece as early as
the fifth and sixth centuries B.C. Even then there
were different "schools'' of medicine, whose disciples
disagreed radically in their methods of treating diseases;
and there were also specialists in certain diseases,
quacks, and charlatans. Some physicians depended
entirely upon external lotions for healing all
disorders; others were "hydrotherapeutists'' or "bath-physicians''; while there were a host of physicians
who administered a great variety of herbs and drugs.
There were also magicians who pretended to heal by
sorcery, and great numbers of bone-setters, oculists,
and dentists.
Many of the wealthy physicians had hospitals, or
clinics, where patients were operated upon and treated.
They were not hospitals in our modern understanding
of the term, but were more like dispensaries, where
patients were treated temporarily, but were not allowed
to remain for any length of time. Certain communities
established and supported these dispensaries for
the care of the poor.
But anything approaching a rational system of
medicine was not established, until Hippocrates of
Cos, the "father of medicine,'' came upon the scene.
In an age that produced Phidias, Lysias, Herodotus,
Sophocles, and Pericles, it seems but natural that the
medical art should find an exponent who would rise
above superstitious dogmas and lay the foundation
for a medical science. His rejection of the supernatural
alone stamps the greatness of his genius. But,
besides this, he introduced more detailed observation
of diseases, and demonstrated the importance that attaches
to prognosis.
Hippocrates was born at Cos, about 460 B.C., but
spent most of his life at Larissa, in Thessaly. He was
educated as a physician by his father, and travelled
extensively as an itinerant practitioner for several
years. His travels in different climates and among
many different people undoubtedly tended to sharpen
his keen sense of observation. He was a practical
physician as well as a theorist, and, withal, a clear and
concise writer. "Life is short,'' he says, "opportunity
fleeting, judgment difficult, treatment easy, but treatment
after thought is proper and profitable.''
His knowledge of anatomy was necessarily very imperfect,
and was gained largely from his predecessors,
to whom he gave full credit. Dissections of the human
body were forbidden him, and he was obliged to
confine his experimental researches to operations
on the lower animals. His knowledge of the structure
and arrangement of the bones, however, was
fairly accurate, but the anatomy of the softer tissues,
as he conceived it, was a queer jumbling together
of blood-vessels, muscles, and tendons. He
does refer to "nerves,'' to be sure, but apparently the
structures referred to are the tendons and ligaments,
rather than the nerves themselves. He was better
acquainted with the principal organs in the cavities of
the body, and knew, for example, that the heart is
divided into four cavities, two of which he supposed
to contain blood, and the other two air.
His most revolutionary step was his divorcing of
the supernatural from the natural, and establishing
the fact that disease is due to natural causes and
should be treated accordingly. The effect of such an
attitude can hardly be over-estimated. The establishment
of such a theory was naturally followed by a
close observation as to the course of diseases and the
effects of treatment. To facilitate this, he introduced
the custom of writing down his observations as he
made them—the "clinical history'' of the case. Such
clinical records are in use all over the world to-day,
and their importance is so obvious that it is almost
incomprehensible that they should have fallen into
disuse shortly after the time of Hippocrates, and not
brought into general use again until almost two thousand
years later.
But scarcely less important than his recognition of
disease as a natural phenomenon was the importance
he attributed to prognosis. Prognosis, in the sense of
prophecy, was common before the time of Hippocrates.
But prognosis, as he practised it and as we understand
it to-day, is prophecy based on careful observation
of the course of diseases—something more than
superstitious conjecture.
Although Hippocratic medicine rested on the belief
in natural causes, nevertheless, dogma and theory held
an important place. The
humoral theory of disease
was an all-important one, and so fully was this theory
accepted that it influenced the science of medicine all
through succeeding centuries. According to this celebrated
theory there are four humors in the body—
blood, phlegm, yellow bile, and black bile. When
these humors are mixed in exact proportions they
constitute health; but any deviations from these proportions
produce disease. In treating diseases the
aim of the physician was to discover which of these
humors were out of proportion and to restore them to
their natural equilibrium. It was in the methods employed
in this restitution, rather than a disagreement
about the humors themselves, that resulted in the various
"schools'' of medicine.
In many ways the surgery of Hippocrates showed a
better understanding of the structure of the organs
than of their functions. Some of the surgical procedures
as described by him are followed, with slight modifications,
to-day. Many of his methods were entirely
lost sight of until modern times, and one, the treatment
of dislocation of the outer end of the collar-bone,
was not revived until some time in the eighteenth
century.
Hippocrates, it seems, like modern physicians, sometimes
suffered from the ingratitude of his patients.
"The physician visits a patient suffering from fever or
a wound, and prescribes for him,'' he says; "on the next
day, if the patient feels worse the blame is laid upon
the physician; if, on the other hand, he feels better,
nature is extolled, and the physician reaps no praise.''
The essence of this has been repeated in rhyme and
prose by writers in every age and country, but the
"father of medicine'' cautions physicians against allowing
it to influence their attitude towards their profession.
Notes
[[62]]
(p. 150). Theodor Gomperz, Greek
Thinkers: a History of Ancient Philosophy (translated from
the German by Laurie Magnes), New York, 1901, pp. 220, 221.
[[63]]
(p. 153). Aristotle's Treatise on
Respiration, ch. ii.
[[64]]
(p. 159). Fairbanks' translation of the fragments of Anaxagoras,
in The First Philosophers of Greece, pp. 239-243.