CATEGORICAL PROPOSITION

in syllogistic or traditional logic, a proposition or statement, in which the predicate is, without qualification, affirmed or denied of all or part of the subject. Thus, categorical propositions are of four basic forms: Every S is P, No S is P, Some S is P, and Some S is not P. These forms are designated by the letters A, E, I, and O, respectively, so that Every man is mortal, for example, is an A-proposition. Categorical propositions are to be distinguished from compound and complex propositions, into which they enter as integral terms; in particular, being assertions of fact rather than of logical connections, they contrast especially with hypothetical propositions, such as If every man is mortal, then Socrates is mortal.