several great idealistic systems of
philosophy. That the Absolute is reason is the central teaching of
them all. Plato, therefore, is the founder and initiator of all
idealism. It is this that gives him his great place in the history of
philosophy. That the Absolute is universal thought, this is what Plato
has contributed to the philosophical speculation of the world. This is
his crowning merit.

But we must go somewhat more into details. We must see how far he
applied this principle successfully to the unravelment of the great
problems of philosophy. In lecturing upon the Eleatics, I said that
any successful philosophy must satisfy at least two conditions. It
must give such an account of the Absolute, that the Absolute is shown
as capable of explaining the world. It must be possible to deduce the
actual world of facts from the first principle. Secondly, not only
must this first principle explain the world; it must also explain
itself. It must be really ultimate, that is, we must not, in order to
understand it, have to refer to anything beyond and outside it. If we
have to do so then our ultimate is not an ultimate at all; our first
principle {236} is not first. That thing by means of which we explain
it must itself be the ultimate reality. And besides being ultimate,
our principle must be wholly intelligible. It must not be a mere
ultimate mystery; for to reduce the whole world to an ultimate mystery
is clearly not to explain it. Our first principle must, in a word, be
self-explanatory. Let us apply this two-fold test to Plato's system.
Let us see, firstly, whether the principle of Ideas explains the
world, and secondly, whether it explains itself.

Does it explain the world? Is the actual existence of things, horses,
trees, stars, men, explained by it? What, in the first place, is the
relation between things and the Ideas? Things, says Plato, are
"copies," or "imitations" of the Ideas. They "participate" in the
Ideas. The Ideas are "archetypal" of things. Now all these phrases are
mere poetic metaphors. They do not really tell us how things are
related to Ideas. But suppose we ignore this, and assume, for the sake
of argument, that we understand what is meant by "participation" and
that things are, in the literal sense, "copies" of Ideas. The question
still remains, why do such copies exist, how do they arise? Now, if
this problem is to be solved, it is not enough to show, merely as a
fact, that, by some mysterious