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L ogic The basic subject-predicate proposition in which a predicate is used to affirm or negate all or some of what a subject indicates. The subject and the predicate are the terms of the proposition. In traditional logic, there are four categorical propositions: (1) the universal affirmative, “All S are P”; (2) the universal negative, “All S are not P”; (3) the particular affirmative, “Some S are P”; and (4) the particular negative, “Some S are not P.” They are respectively abbreviated as A, E, I, O. Categorical propositions are so called in order to distinguish them from modal propositions (which express possibility or necessity), conditional propositions, and other complex propositions. If both of the premises and the conclusion of a syllogism are expressed in the form of a categorical proposition, then the syllogism is called a categorical syllogism. “In a categorical proposition, there is always something, the ‘predicate’, which is either affirmed or denied of something else, the ‘subject’.” Prior, Formal Logic ... log in or subscribe to read full text