After Asian philosophy, this 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.