Kant on Demarcation and Discovery

Kant makes two claims in the Critique of Pure Reason that anticipate concerns of twentieth-century philosophy of science. The first, that the understanding and sensibility are constitutive of knowledge, while reason is responsible for transcendental illusion, amounts to his solution to Karl Popper’s “problem” of demarcating science from pseudoscience. The second, that besides these constitutive roles of the understanding and sensibility, reason is itself needed to discover new empirical knowledge, anticipates Hans Reichenbach’s distinction between the “contexts” of justification and discovery. Unlike Reichenbach, however, who thinks that there can be a “logic” only of justification, Kant provides what amounts to a logic of discovery. Though Kant’s broader concerns are not Popper’s or Reichenbach’s, using theirs as framing devices reveals two otherwise unnoticed things about the Critique of Pure Reason. First, besides its general epistemological and metaphysical aims, the Critique lays groundwork for the twentieth century’s specialized field of the philosophy of science. Second, Kant’s solution to the demarcation problem contradicts his logic of discovery, so in this instance the Critique is too ambitious.