Volume 18, 1993
D. F. Siemens, Jr.
On Wiebe’s “Existential Assumptions for Aristotelian Logic”
This comment calls attention to the nature of the Aristotelian and classical logics, and the difficulty of representing their judgments and inferences by means of Venn diagrams. The meaning of ‘all’ in the different calculi produces problems. A second problem is that the specification of existence in Venn diagrams for statements and arguments cannot be restricted to a single class, overlooked by Wiebe. This problem is further complicated by his adoption of classical (Renaissance) syllogistic, which is inconsistent. Aristotle’s term logic is consistent. So also is the medieval extension, though the inclusion of singular premisses renders it less perspicuous though more flexible.