Kant understands "logic" in the literal sense as the theory of thought, and thus as the theory of the understanding as the faculty which is essentially complementary to sensibility. His "transcendental logic" is not concerned, as logic typically is, with the structures of formal inference, but with a kind of substantive knowledge. In this connection he investigates the pre-empirical contribution of the understanding, namely those "pure concepts' which he follows Aristotle in calling "categories". The philosophers of early modernity demoted Aristotle's so-called organon, his canonic writings on logic and theory of scientific knowledge, to the status of the "ancient organon", treating it as a sterile art of demonstration that was incapable of yielding fresh knowledge¹ and that should therefore be replaced by an art of discovery. Their attempt must nonetheless be regarded as a failure since neither Bacon in his New Organon, nor Giordano Bruno previously, nor Descartes, Leibniz, Vico, or Wolff subsequently, actually succeeded in developing a new art of discovery that could properly be compared with the older art of demonstration.