A Note on Ockham's Theory of the Modes of Common Personal Supposition

Abstract

The last half of this century has seen an amazingly energetic and resourceful effort to understand Ockham's supposition theory. The result is that we are much more sophisticated in our approach to the subject today than anybody could have been before. Yet, despite the fact that we now have, not only critical editions and translations of Ockham's logic texts, but also elaborately formal reconstructions of the theory of supposition itself,1 there is no clear consensus about what Ockham was up to in presenting his theory of the Modes of Common Personal Supposition (hereafter, following Alfred Freddoso,2 MCPS). Beginning with the account Philotheus Boehner offers in his Medieval Logic,3 the clearest and most intriguing suggestion has been that Ockham's theory of MCPS is a theory of quantification. According to that theory both the subject term and the predicate term of each of the standard categorical propositions, A, E, I and O, are quantified, either explicitly, as is the case with the subject term of this A proposition,