Heraclitus and the Identity of Opposites

Abstract

T he purpose of this paper is to discuss the relationship between opposites which Heraclitus appears to describe in terms of identity or unity. In particular an attempt will be made to determine firstly what Heraclitus means when he says that opposites are so auro or ev, and secondly, how far it is correct to interpret this relationship in terms of other elements in Heraclitus' philosophical outlook. The identity of opposites as such was not influenitial on the subsequent history of Greek philosophy. Parmenides, in emphasizing the separateness of opposites (albeit as the 'opinion of mortals'), explicitly rejected any idea of their identity and incidentally foreshadowed the separation of opposites in formal logic, from which such notions as the identity of opposites were, by definition, excluded.1 Anaxagoras based his assertion of the inseparability and, in a sense, the identity of opposites,2 upon a belief in the infinite divisibility of matter; no piece of matter containing one opposite would entirely exclude others. What Heraclitus appeared to represent as a contradiction was shown by Anaxagoras to be literally true, but, at the same time, explicable on the basis of an original theory of matter.3 At Theaetetus 152 c-e, Plato considered the doctrine that objects simultaneously possess opposite attributes, and linked this doctrine very closely with the doctrine of flux; if everything is always in a process of change