Medieval Logic in its stage of maturity in the 14th century has become an essentially consequential logic. A consequential logic, however, is a highly formalistic logic.
Unfortunately, this peak of the development of medieval logic was reached at the beginning of a rapid decline of scholastic philosophy in general. To interpret this chronological coincidence as a causal relation, and to blame the high standard of 14th-century logic for the ruin of scholastic metaphysics, appears to us extremely ironical. We are not convinced that scholastic metaphysics has to be afraid of an inexorable logic. On the contrary, scholastic metaphysics, in contrast with modern metaphysical systems, has called for logical rigour and has always been averse to any kind of intuitionism. We are rather convinced that scholastic logic in the 14th century finally reached a stage by which it was in a condition to justify its basic metaphysical inferences. For it is a fact that the proofs of the existence of God developed during the Middle Ages, and definitely the proofs of St. Thomas, cannot be sufficiently developed and justified with a logic content with syllogistics. This has been shown by Salamucha as regards the first of the five ways of the Common Doctor. It was likewise stated already in the Middle Ages as regards the proof of the existence of God advanced by Scotus. Petrus Thomae, an immediate disciple of the Subtle Doctor, expressly states that consequences holding in virtue of an extrinsic means, and hence not reducible to syllogisms, are used the construction of his proof.
Historically speaking, then, medieval logic had finally caught up with metaphysics, when, for well-known exterior reasons, a general decline of scientific culture began.