categorical syllogism

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A conventional syllogism of the type introduced by the Greek philosopher Aristotle (384–322bc), and used by almost all his successors, in which the propositions (1) are expressed in terms of category membership, using the four standard categorical proposition forms All S are P, No S are P, Some S are P, and Some S are not P. Examples of propositions that might be used in a categorical syllogism are All men are mortal, No wombats play tennis, Some thunderstorms are thrilling, and Some swans are not white. A categorical syllogism cannot express a logical argument containing non-categorical propositions such as Elizabeth is the mother of Charles. See also modal logic.

Subjects: Psychology.

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