Anaxagoras

Anaxagoras came from Clazomenae in Asia Minor and settled in Athens around the 460s BCE, the first person to teach philosophy there. He was friend and teacher to Pericles and an influence on Euripides. Pericles' political enemies prosecuted him for impiety because he said the sun was a red-hot stone larger than the Peloponnese. Forced to leave Athens, he spent his last years at Lampsacus, where the citizens raised an altar to him.

His physics answers Parmenides: nothing truly comes to be or perishes, there is only mixture and separation. But unlike Empedocles' four roots, he held that matter is infinitely divisible and that everything contains a portion of everything, 'in everything there is everything'. Bread can become flesh and bone because bread already contains seeds of flesh and bone.

What sets the original mixture spinning and separating is Nous, Mind. It is the finest and purest of things, mixed with nothing, knowing all and ruling all. The young Socrates was thrilled to read this, expecting at last an explanation of the world by purpose, only to find that Anaxagoras let Mind give a single push and explained the rest mechanically. Aristotle said he stood out like a sober man among drunkards.