ANTITHESIS (ἀντίθεσις). – Opposition in meaning between two notions or judgments. The terminology is Aristotle’s, for whom a. has a generic scope, encompassing both contradictory and contrary opposition (cf. De Interpr., chap. 7, 17 b 16; ibid., chap. 6, 17a, 33). In Kant it acquired a more concrete meaning, denoting a proposition contradictorily opposed to the thesis and of equal noetic value, hence the genesis of the antinomies of Pure Reason (cf. Critica della Ragion pura, Bari 1940, part 2, p. 344 ff.). In Fichte, Hegel, and idealism in general, a. is the second dialectical moment of Spirit
(I, Idea), through which negation or opposition or contradiction is posited, to be resolved and overcome in the synthesis. Ugo Viglino