He has made
no attempt to complete it. All he has done is to give us numerous
examples. And this is, in reality, all that can be expected, for the
number of Ideas is obviously infinite, and therefore the task of
arranging them cannot be completed. There is, however, one important
defect in the dialectic, which Plato ought certainly to have remedied.
The supreme Idea, he tells us, is the Good. This, as being the
ultimate reality, is the ground of all other Ideas. Plato ought
therefore to have derived all other Ideas from it, but this he has not
done. He merely asserts, in a more or less dogmatic way, that the Idea
of the Good is the highest, but does nothing to connect it with the
other Ideas. It is easy to see, however, why he made this assertion.
It is, in fact, a necessary logical outcome of his system. For every
Idea is perfection in its kind. All the Ideas have perfection in
common. And just as the one beauty is the Idea which presides over all
beautiful things, so the one perfection must be the supreme Idea which
presides {201} over all the perfect Ideas. The supreme Idea,
therefore, must be perfection itself, that is to say, the Idea of the
Good. On the other hand it might, with equal force, be argued that
since all the Ideas are substances, therefore the highest Idea is the
Idea of substance. All that can be said is that Plato has left these
matters in obscurity, and has merely asserted that the highest Idea is
the Good.

Consideration of the Idea of the Good leads us naturally to enquire
how far Plato's system is teleological in character. A little
consideration will show that it is out and out teleological. We can
see this both by studying the many lower Ideas, and the one supreme
Idea. Each Idea is perfection of its kind. And each Idea is the ground
of the existence of the individual objects which come under it. Thus
the explanation of white objects is the perfect whiteness, of
beautiful objects the perfect beauty. Or we may take as our example
the Idea of the State which Plato describes in the "Republic." The
ordinary view is that Plato was describing a State which was the
invention of his own fancy, and is therefore to be regarded as
entirely unreal. This is completely to misunderstand Plato. So far was
he from thinking the ideal State unreal, that he regarded it, on the
contrary, as the only real State. All existent States, such as the
Athenian or the Spartan, are unreal in so far as they differ from the