Anaxagoras
Ancient Greek · Europe · 500 to 428 BCE
Greek thinker who brought philosophy to Athens and said a ruling mind set the world in order.
What it is
Anaxagoras was a Greek thinker from Clazomenae, a port city on the western coast of what is now Turkey. He lived from about 500 to 428 BCE and is credited with bringing philosophy and the study of nature to Athens, where he spent a good part of his life as a friend and student of the statesman Pericles.
He is best known for two ideas. The first is that everything contains a portion of everything else. The second is that a Mind, which is not mixed with other things, set the world turning and gave it order.
The main ideas
- Nothing is made or lost. Like Parmenides, he held that nothing truly comes into being or perishes. What looks like birth and death is the rearranging of what was already there.
- A portion of everything in everything. Every kind of stuff contains some of every other kind. This was his way of explaining how change is possible: a thing can seem to become something new when one ingredient grows to predominate.
- Mind sets things going. Mind (the Greek word is nous) started a great rotation in the original mixture. As it spread, the stuff separated into the heavens and the earth, and Mind is said to have ordered everything.
- Heavens made of stone. He held that the sun and other heavenly bodies are red-hot stones. He also explained eclipses as the screening of one body by another.
What it looks like in practice
Imagine someone looking at a loaf of bread and wondering how what they eat becomes bone and hair. Anaxagoras reasoned that if hair can come from bread, then bread must already hold some hair, and every other thing, hidden in tiny amounts. This is an illustration of his line of thought, not a passage from his book.
Books and moments
- One book. He wrote a single book on nature. It is lost, but in Plato's Apology Socrates says it could be bought for a drachma at most, and later writers kept parts of it.
- A stone from the sky. A stone fell from the heavens, and Anaxagoras was credited with having predicted it. The accounts do not settle whether his idea about the heavenly bodies came before or after the fall.
- Trial and exile. Charged with impiety, in part for saying the sun is a red-hot stone, he left Athens for Lampsacus. The dates of his time in Athens, of his book and of his trial are disputed, and he died in 428.
Questions and criticism
- What is Mind? His surviving words seem to give it contradictory properties: it is said to be mixed with nothing, and yet to be in some things. Its nature is left open.
- A cause with no purpose? In Plato's Phaedo, Socrates says he was delighted to hear that Mind orders everything for the best, and then disappointed that Anaxagoras explained things by air, water and similar causes. Aristotle complained in a similar way.
- Why was he tried? The charge was impiety, and his views about the heavens played a part. One account adds a political motive, an attack on Pericles through his teacher. It is fair to ask how much each mattered.
Close neighbours
Parmenides set the problem of change that he answered. Empedocles, a contemporary, gave a different answer in terms of four roots. Socrates read him with hope and was let down.
Written by epchē in our own words, and checked against independent sources on 29 October 2026. The sources are listed below.
Who they connect to
Influenced
- Socrates · Plato's Phaedo has Socrates describe reading him as a young man. (scholars disagree about this link)
Other Ancient Greek thinkers
- Thales of Miletus · 624 to 546 BCE
- Anaximander · 610 to 546 BCE
- Anaximenes · 586 to 526 BCE
- Pythagoras · 570 to 495 BCE
- Xenophanes · 570 to 475 BCE
- Heraclitus · 535 to 475 BCE
- Parmenides · 515 to 450 BCE
- Empedocles · 494 to 434 BCE
- Zeno of Elea · 490 to 430 BCE
- Leucippus · 480 to 420 BCE
Sources we used
- Anaxagoras · Stanford Encyclopedia of Philosophy, read on 29 October 2026
- Anaxagoras · Internet Encyclopedia of Philosophy, read on 29 October 2026