 The first half of the Critique of Pure Reason argues that we can only obtain substantive knowledge of the world via sensibility and understanding. Very roughly, our capacities of sense experience and concept formation cooperate so that we can form empirical judgments. The next large section—the “Transcendental Dialectic”—demolishes reason’s pretensions to offer knowledge of a “transcendent” world, that is, a world beyond that revealed by the senses. “Dialectic,” says Kant, is “a logic of illusion” (A293): so in his vocabulary, a dialectical idea is empty or false.