us something irrational. The problem can only be solved
by showing us that somehow, in spite of appearances, it
is rational that evil should exist. Show us this, and evil
is explained. Explanation of a thing, then, means showing
that the thing is rational. Now we can ask that everything
else in the world should be shown to be rational. But we
cannot demand that the philosopher shall show that rea-
son is rational. This is absurd. Reason is what is already
absolutely rational. It is what explains itself. It is its own
reason. It is a self-explanatory principle. This, then, must
be the principle of which we are in search. The Absolute,
we said, must be a self-explanatory principle, and there is
only one such, namely, reason. The Absolute, therefore, is
reason.
It was the greatness and glory of Plato to have seen this,
and thereby to have become the founder of all true philos-
ophy. For to say that the Absolute is concepts is the same
as saying it is reason. It might seem, then, that Plato has
satisfied the second canon of criticism. He takes as first
principle a self-explanatory reality. But we cannot quite so
quickly jump to this conclusion. After all, the mere word
reason is not a key which will unlock to us the doors of the
universe. Something more is necessary than the mere word.
We must, in fact, be told what reason is. Now there are
two senses in which we might ask the question, what reason
is, one of which is legitimate, the other illegitimate. It is
illegitimate to ask what reason is, in the sense of asking
that it shall be explained to us in terms of something else,
which is not reason. This would be {242} to give up our
belief that reason is its own reason. It would be to seek the
reason of reason in something which is not reason. It would
be to admit that reason, in itself, is not rational. And this
is absurd. But it is legitimate to ask, what reason is, mean-
ing thereby, what is thecontentof reason. The content of
reason, we have seen, is concepts. But what concepts? How
are we to know whether any particular concept is part of the
system of reason or not? Only, it is evident, by ascertain-
ing whether it is a rational concept. If a concept is wholly
rational, then it is a part of reason. If not, not. What we
need, then, is a detailed account of all the concepts which
reason contains, and a proof that each of these concepts is
really rational. It is obvious that only in this way can we
make a satisfactory beginning in philosophy. Before we can
show that reason explains, that is, rationalizes the world,
we must surely first show that reason itself is rational, or
rather, to be more accurate, thatour conceptionof reason
is rational. There must not be any mere inexplicable facts,
any mysteries, any dark places, in our notion of reason.
It must be penetrated through and through by the light of
reason. It must be absolutely transparent, crystalline. How
can we hope to explain the world, if our very first principle
itself contains irrationalities?Each concept then must prove itself rational. And this
means that it must be a necessary concept. A necessary
proposition, we saw, is one, such as that two and two equal
four, the opposite of which is unthinkable. So for Plato’s
Ideas to be really necessary it ought to be logically im-
possible for us to deny their {243} reality. It ought to
be impossible to think the world at all without these con-
cepts. To attempt to deny them ought to be shown to be