i. Introductory remarks 1 Plato, but not Socrates, concluded that the
Forms are substances. Whether the Forms are substances is not an issue
that Socrates had in mind. He did not deny it, but neither did he affirm
it. If Socrates were asked a series of questions designed to determine
whether he believed that the Forms are substances, he would admit that
he had no opinion about this philosophical issue. Unlike Plato, Socrates
was not a metaphysician. The same, of course, would not have always been
true of Plato. Unlike Socrates, he was a metaphysician. At some point in
his career, and at least by the time of the Phaedo and the Republic,
Plato did what Socrates never thought to do. Plato considered the
question and concluded that the Forms are substances. Although this
development occurred more than two thousand years ago, time has not
eclipsed its importance. It is one of the most seminal events in the
history of the philosophy. With his defense of Socrates's method of
intellectual inquiry, and the development of his Theory of Forms, Plato
caused a now familiar cluster of metaphysical and epistemological issues
to become central to philosophy.