The unity of opposites was first suggested to the western view by
Heraclitus (c. 535 – c. 475 BC), a
pre-Socratic Greek thinker.
Philosophers had for some time been contemplating the notion of opposites.
Anaximander posited that every element had an opposite, or was connected to an opposite (water is cold, fire is hot). Thus, the material world was said to be composed of an infinite, boundless
apeiron from which arose the
elements (earth, air, fire, water) and pairs of opposites (hot/cold, wet/dry). There was, according to Anaximander, a continual war of opposites.
Anaximenes of Miletus, a student and successor of Anaximander, replaced this infinite, boundless
arche with air, a known element with neutral properties. According to Anaximenes, there was not so much a war of opposites, as a continuum of change. Heraclitus, however, did not accept the
Milesian monism and replaced their underlying material arche with a single, divine law of the universe, which he called
Logos. The universe of Heraclitus is in constant change, while remaining the same. That is to say, when an object moves from point A to point B, a change is created, while the underlying law remains the same. Thus, a unity of opposites is present in the universe simultaneously containing difference and sameness. An
aphorism of Heraclitus illustrates the idea as follows: The road up and the road down are the same thing. (
Hippolytus,
Refutations 9.10.3) This is an example of a
compresent unity of opposites. For, at the same time, this slanted road has the opposite qualities of ascent and descent. According to Heraclitus, everything is in constant flux, and every changing object contains at least one pair of opposites (though not necessarily simultaneously) and every pair of opposites is contained in at least one object. Heraclitus also uses the succession of opposites as a basis for change: Cold things grow hot, hot things grow cold, a moist thing withers, a parched thing is wetted. (
DK B126) An object persists despite opposite properties, even as it undergoes change. ==Medieval philosophy==