categorical proposition

In syllogistic, a proposition in which the predicate is 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 are designated by the letters A, E, I, and O, respectively; thus, "Every man is mortal" is an A-proposition. Categorical propositions are to be distinguished from compound and complex propositions, into which they can enter as integral terms. In particular, they contrast especially with hypothetical propositions, such as "If every man is mortal, then Socrates is mortal."

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▪ logic

      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.”

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