s it to the reader to apply them to the theory of Ideas.
Whether the Absolute is one or many, Being or not-being, can be
decided independently of any particular theory of the nature of the
Absolute, and therefore independently of Plato's own theory, which was
that the Absolute consists of Ideas. Plato does not accept the Eleatic
abstraction. The One cannot be simply one, for every unity must
necessarily be a multiplicity. The many and the One are correlative
ideas which involve each other. Neither is thinkable without the
other. A One which is not many is as absurd an abstraction as a whole
which has no parts. For the One can only be defined as that which is
not many, and the many can only be defined as the not-one. The One is
unthinkable except as standing out against a background of the many.
The idea of the One therefore involves the idea of the many, and
cannot be thought without it. Moreover, an abstract One is unthinkable
and unknowable, because all thought and knowledge consist in applying
predicates to subjects, and all predication involves the duality of
its subject.

Consider the simplest affirmation that can be made about the One,
namely, "The One is." Here we have two things, "the One," and "is,"
that is to say, being. The proposition means that the One is Being.
Hence the One is two. Firstly, it is itself, "One." Secondly, it is
"Being," and the proposition affirms that these two things are one.
Similarly with any other predicate we apply to the One. Whatever we
say of it involves its duality. Thus we find that all systems of
thought which {197} postulate an abstract unity as ultimate reality,
such as Eleaticism, Hinduism, and the system of Spinoza, attempt to
avoid the difficulty by saying nothing positive about the One. They
apply to it only negative predicates, which tell us not what it is,
but what it is not. Thus the Hindus speak of Brahman as form_less_,
_im_mutable, _im_perishable, _un_moved, _un_created. But this, of course,
is a futile expedient. In the first place, even a negative predicate
involves the duality of the subject. And, in the second place, a
negative predicate is always, by implication, a positive one. You
cannot have a negative without a positive. To deny one thing is to
affirm its opposite. To deny motion of the One, by calling it the
unmoved, is to affirm rest of it. Thus a One which is not also a many
is unthinkable. Similarly, the idea of the many is inconceivable
without the id