A man’s self, [Kant] maintains, like everything else, is a part of reality—it,
too, is something in itself—and if reality is unknowable, then so is a man’s
self. A man is able, Kant concludes, to know only his phenomenal ego, his self
as it appears to him (in introspection); he cannot know his noumenal ego, his
“ego as it is in itself.” Man is, therefore, a creature in metaphysical
conflict. He is so to speak a metaphysical biped, with one (unreal) foot in the
phenomenal world and one (unknowable) foot in the noumenal world.