polemic against Plato’s theory of Ideas, because his own
system was in effect simply an attempt to overcome the
defects which he found in Plato. The main heads of this
polemic are the following:—
(1) Plato’s Ideas do not explain the existence of things. To
explain why the world is here is after all the main problem
of philosophy, and Plato’s theory fails to do this. Even
admitting that, say, the Idea of whiteness exists, we cannot
see how it produces white objects.
(2) Plato has not explained the relation of Ideas to things.
Things, we are told, are “copies” of Ideas, and “participate”
in them. But how are we to understand this “participa-
tion”? In using such phrases, says Aristotle, Plato is giving
no real account of the relationship, but is merely “uttering
poetic metaphors.”
(3) Even if the existence of things is explained by the Ideas,
their motion is not. Suppose that the Idea of whiteness
produces white things, the Idea of beauty beautiful things,
and so on, yet, since the Ideas themselves are immutable
and motionless, so will be the world which is their copy.
Thus the universe would be {263} absolutely static, like
Coleridge’s “painted ship upon a painted ocean.” But the
world, on the contrary, is a world of change, motion, life, be-
coming. Plato makes no attempt to explain the unceasing
becoming of things. Even if the Idea of whiteness explains
white objects, yet why do these objects arise, develop, de-
cay, and cease to exist? To explain this there must be some
principle of motion in the Ideas themselves. But there is
not. They are immovable and lifeless.
(4) The world consists of a multitude of things, and it is the
business of philosophy to explain why they exist. By way of
explanation Plato merely assumes the existence of another
multitude of things, the Ideas. But the only effect of this is
to double the number of things to be explained. How does
it help thus to duplicate everything? And Aristotle likens
Plato to a man who, being unable to count with a small
number, fancies that, if he doubles the number, he will find
it easier to count.(5) The Ideas are supposed to be non-sensuous, but they
are, in fact, sensuous. Plato thought that a non-sensuous
principle must be sought in order to explain the world of
sense. But not being able to find any such principle, he
merely took the objects of sense over again and called them
non-sensuous. But there is, in fact, no difference between
the horse and the Idea of the horse, between the man and
the Idea of the man, except a useless and meaningless “in-
itself” or “in-general” attached to each object of sense to
make it appear something different. The Ideas are nothing
but hypostatized things of sense, and Aristotle likens them
to the anthropomorphic gods of the popular religion. “As
{264} these,” he says, “are nothing but deified men, so the
Ideas are nothing but eternalized things of nature.” Things
are said to be copies of Ideas, but in fact the Ideas are only
copies of things.(6) Next comes the argument of the “third man,” so called
by Aristotle from the illustration by which he explained it.
Ideas are assumed in order to explain what is common to
many objects. Wherever there is a common element there
must be an Idea. Thus there is a common element in all