СИЛЛОГИЗМ ФИГУРЫ И МОДУСЫ

Syllogism, Figures and Moods of

Varieties of a syllogism (see Syllogistic) which depend on the position of the middle term in the premisses and their number and type (general assertions, particular assertions, general negations, particular negations; see Judgement).

In the first figure the middle term is the subject in the major premiss and the predicate in the minor; in the second figure it is the predicate in both premisses; in the third it is the subject in both premisses. These figures were introduced by Aristotle. The fourth figure, in which the middle term is the predicate in the major premiss and the subject in the minor, was added by Aristotle's followers.

Classical logic has 19 moods; contemporary logic excludes, as not applicable in all cases, four moods which lose their general significance when they deal with empty sets (for example, "all golden mountains are golden"; "all golden mountains are mountains", but from this it does not follow that some mountains are golden—example given by Russell).