Anaxagoras was born about 510 BC in Clazomenae, Ionia, at the time part of the Persian Empire and today located on what is the west coast of Turkey. He was the scion of aristocratic landowners but renounced his patrimony to study philosophy—with whom, however, is not known. By the middle of the fifth century, he arrived in Athens, where he became a protégé of Pericles, the great statesman and general. He lived in Athens for at least two decades before he was banished (perhaps in 437/436) on a charge of “impiety” and perhaps for harboring political sympathy with the Persians. He settled in Lampsacus, where he died about 428 BC.
Despite his prominence among the Pre-Socratic philosophers, the works of Anaxagoras have suffered the same fate as those of his fellow Pre-Socratics. What we know of it comes from fragments cited by later philosophers and commentators.
Anaxagoras is best described as a cosmologist. His theory of the origin of the universe is that all things existing today existed from the beginning, but in infinitesimally small fragments of themselves combined into an amorphous, chaotic mixture. Although infinite in number, the fragments existed in parts that were either homogeneous or heterogeneous. The arrangement of this infinitude of things, beginning with the segregation of like from unlike, was achieved by the Nous, or Cosmic Mind. As described by the sixth century AD Neoplatonist Simplicius of Cilicia (c. 490-c.560), the Nous set the particle mixture into rotary motion, the action of which effected shifts in the proportions of the ingredients in various portions of the mixture. The rotation expanded the mixture, thereby producing the stillevolving world (or universe), including what we currently perceive.
The concept of a Cosmic Mind is the most familiar philosophical artifact that has come down to us from Anaxagoras. As the philosopher imagined it, it was no less infinite than the material on which it operated, yet it existed independently of and apart from that material, a pure and finer substance, perfectly uniform, encompassing all knowledge and all power. Evidence of the existence of this Nous is the life around us, which it both animates and rules.
Through time, the still-rotating universe changes, producing new aggregations and new disruptions. Yet the original mixture of things is neither destroyed nor entirely converted from chaos to order. For this reason, everything that exists contains within its structure fragments of other things. All material reality is heterogeneous in composition. Only the preponderance of some homogeneous components gives each thing what we perceive as its distinctive character.
