of the space-time manifold. But these individual contents—that go by the technical name of intuitions—simply in themselves will never yield knowledge unless and until they can be thought. For knowledge is expressed in a judgment, and there is no judgment without concepts (and hence categories). Kant put it memorably: “Thoughts without content are empty, intuitions without concepts are blind.”8 From this two things follow: (1) We can never know things as they are in themselves, but only as they