Anaxagoras was a Pre-Socratic Greek philosopher. Born in Clazomenae at a time when Asia Minor was under the control of the Persian Empire, Anaxagoras was the first to bring philosophy to Athens. According to Diogenes Laertius and Plutarch, in later life he was charged with impiety and went into exile in Lampsacus; the charges may have been political, owing to his association with Pericles, if they were not fabricated by later ancient biographers.
Responding to the claims of Parmenides on the impossibility of change, Anaxagoras described the world as a mixture of primary imperishable ingredients, where material variation was never caused by an absolute presence of a particular ingredient, but rather by its relative preponderance over the other ingredients; in his words, "each one is... most manifestly those things of which there are the most in it". He introduced the concept of Nous as an ordering force, which moved and separated out the original mixture, which was homogeneous, or nearly so.
He also gave a number of novel scientific accounts of natural phenomena.