Anaxagoras
c. 500–428 BC
Introduced Mind as the ordering principle of the cosmos, and was prosecuted for saying the sun is a burning stone.
Anaxagoras was a Pre-Socratic philosopher from Clazomenae who brought philosophy to Athens and was eventually prosecuted for impiety there.
Everything in everything
He faced the problem Parmenides had created: if nothing comes from nothing, how does anything change? His answer was that nothing does come to be. Every thing contains a portion of every other thing, and what we call change is a rearrangement of proportions.
Hair can come from food that is not hair because the food already contains some hair. A thing is named for whatever predominates in it, not for what it exclusively contains.
Nous
His distinctive move was to add an ordering principle. Mind — nous — is unmixed with anything else, and it set the original mixture rotating, which separated things out into the arrangement we observe.
This is the first appearance in Greek thought of intelligence as a cosmic cause, and it made a strong impression. Plato has Socrates describe his excitement on hearing of it and then his disappointment: Anaxagoras invokes Mind to start the process and then explains everything afterwards mechanically, without ever showing that the arrangement is good. The complaint is the origin of the demand for teleological explanation. See telos.
The trial
He held that the sun is a red-hot stone somewhat larger than the Peloponnese, and the moon a body of earth reflecting its light. Both claims were astronomically reasonable and religiously intolerable, since the sun was a god. He was prosecuted for impiety and left Athens, in what is usually read as an attack on his associate Pericles.
The episode is the earliest recorded case of a philosopher prosecuted for a scientific claim, seventy years before Socrates.
Questions
Who was Anaxagoras?
A Pre-Socratic philosopher (c. 500–428 BC) who brought philosophy to Athens, held that everything contains a portion of everything, and introduced Mind as the cosmic ordering principle.
What did Anaxagoras mean by Nous?
Mind, understood as unmixed with anything else and as the cause that set the original mixture rotating, separating things into the world we observe. It is the first cosmic intelligence in Greek thought.
Why was Anaxagoras prosecuted?
For impiety, after claiming the sun is a red-hot stone rather than a god. It is the earliest recorded prosecution of a philosopher for a scientific claim.