Ideas agree in, but all the rest falls outside it. Thus the
Idea of whiteness is perfect in its kind. And as all Ideas
are likewise perfect, the highest Idea is that in which they
all agree, namely, perfection itself. But this means that
the perfection of the Idea of whiteness is contained in the
supreme Idea, but its specific character in which it differs
from other Ideas is excluded. Its specific character is just
its whiteness. Thus the perfection of whiteness is contained
in the Good, but its whiteness is not. Consequently it is
impossible to deduce whiteness from the Good, because the
Good does not contain whiteness. You cannot get out of it
what is not in it. When Plato deduced the many from the
one, he did so only by showing that the One contains the
many. He cannot deduce whiteness from goodness, because
goodness does not contain whiteness.
The lower Ideas thus have not the character of necessity.
They are mere facts. And the hope that we shall find their
necessity in the supreme Idea fails. But suppose we waive
this. Suppose we grant that there must be an Idea of white-
ness, because there is an Idea of the Good. Then why is
there an Idea of the Good? What is the necessity of that?
We cannot see any necessity in it. What we said of the
other Ideas applies with equal force to the highest Idea. The
Good may be a necessary Idea, but Plato has not shown it.
Thus, though Plato named reason as the Absolute, {246}
and though reason is a self-explanatory principle, his ac-
count of the detailed content of reason is so unsatisfactory
that none of the concepts which he includes in it are really
shown to be rational. His philosophy breaks down upon
the second test as it did upon the first. He has neither
explained the world from the Ideas, nor has he made the
Ideas explain themselves.There is one other defect in Plato’s system which is of cap-
ital importance. There runs throughout it a confusion be-
tween the notions of reality and existence. To distinguish
between existence and reality is an essential feature of all
idealism. Even if we go back to the dim idealism of the
Eleatics, we shall see this. Zeno, we saw, denied motion,
multiplicity, and the world of sense. But he did not deny
the existence of the world. That is an impossibility. Even if
the world is delusion, the delusion exists. What he denied
was the reality of existence. But if reality is not existence,
what is it? It is Being, replied the Eleatics. But Being
does not exist. Whatever exists is this or that particular
sort of being. Being itself is not anywhere to be found.
Thus the Eleatics first denied that existence is reality, and
then that reality exists. They did not themselves draw this
conclusion, but it is involved in their whole position.With a fully developed idealism, like Plato’s, this ought to
be still clearer. And, in a sense, it is. The individual horse
is not real. But it certainly exists. The universal horse is
real. But it does not exist. But, upon this last point, Plato
wavered and fell. He cannot resist the temptation to think
of the absolute reality as existing. And consequently the
Ideas are {247} not merely thought as the real universal
in the world, but as having a separate existence in a world
of their own. Plato must have realised what is, in truth,
involved in his whole position, that the absolute reality has
no existence. For he tells us that it is the universal, and
not any particular individual thing. But everything that