whose reality does not flow into it from anything else, but
which is the source of its own reality. It is self-caused, and
self-determined. It is the ground of other things, but itself has no
ground except itself. For example, if we believe the popular Christian
idea that God created the world, but is Himself an ultimate and
uncreated being, then, since the world depends for its existence upon
God, but God's existence depends only upon Himself, God is a substance
and the world is not. In this sense the word is correctly used in the
Creed where it speaks of God as "three persons, but one substance."
Again, if, with the Idealists, we think that mind is a self-existent
reality, and that matter owes its existence to mind, then in that case
matter is not substance, but mind is. In this technical sense the
Ideas are substances. They are absolute and ultimate realities. {188}
Their whole being is in themselves. They depend on nothing, but all
things depend on them. They are the first principles of the universe.

Secondly, the Ideas are universal. An Idea is not any particular
thing. The Idea of the horse is not this or that horse. It is the
general concept of all horses. It is the universal horse. For this
reason the Ideas are, in modern times, often called "universals."

Thirdly, the Ideas are not things, but thoughts. There is no such
thing as the horse-in-general. If there were, we should be able to
find it somewhere, and it would then be a particular thing instead of
a universal. But in saying that the Ideas are thoughts, there are two
mistakes to be carefully avoided. The first is to suppose that they
are the thoughts of a person, that they are your thoughts or my
thoughts. The second is to suppose that they are thoughts in the mind
of God. Both these views are wrong. It would be absurd to suppose that
our thoughts can be the cause of the universe. Our concepts are indeed
copies of the Ideas, but to confuse them with the Ideas themselves is,
for Plato, as absurd as to confuse our idea of a mountain with the
mountain itself. Nor are they the thoughts of God. They are indeed
sometimes spoken of as the "Ideas in the divine mind." But this is
only a figurative expression. We can, if we like, talk of the sum of
all the Ideas as constituting the "divine mind." But this means
nothing in particular, and is only a poetical phrase. Both these
mistakes are due to the fact that we find it difficult to conceive of
thoughts without a