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.
