# Philolaus explained — The Lives and Opinions of Eminent Philosophers

> Chapter companion for The Lives and Opinions of Eminent Philosophers by Diogenes Laërtius.

## What happens

Philolaus, a Pythagorean from Crotona, was suspected of plotting tyranny and was killed by his fellow citizens. He was the first to write on natural philosophy among the Pythagoreans, teaching that everything is produced by harmony and necessity, and that the earth moves in a circle. His single book was reportedly purchased by Plato and used as a source for the Timaeus.

## Themes in this chapter

### Natural Philosophy and Cosmology

Philolaus was the first Pythagorean to write on natural philosophy, teaching that the earth moves in a circle and that all things arise from harmony and necessity.

### Death and Legacy

Philolaus was killed by his fellow citizens due to suspicion of tyranny; his single book influenced Plato's Timaeus.

## Character check-ins

### Philolaus

A Pythagorean from Crotona, pupil of Pythagoras, first to write a treatise on natural philosophy; died under suspicion of tyranny.

### Plato

Wrote to Dion to purchase the books of Pythagoras from Philolaus; later bought Philolaus's book in Sicily.

### Pythagoras

Philolaus was a pupil of Pythagoras.

### Dionysius of Heraclea

Plato visited his court in Sicily and obtained Philolaus's book.

## Key lines

> His theory was that everything was produced by harmony and necessity.

Philolaus believed that all things come into being through a combination of harmony and necessity.

_Core tenet of Philolaus's natural philosophy._

> And he was the first person who affirmed that the earth moved in a circle; though some attribute the assertion of this principle to Icetas of Syracuse.

Philolaus was the first to claim that the earth revolves in a circular motion, though some credit Icetas of Syracuse with this idea.

_Early heliocentric or geokinetic theory attributed to Philolaus._

> But nature in the world has been composed of bodies infinite and finite, and so is the whole world and all that is in it.

The world's nature is made up of both infinite and finite bodies, and this applies to the entire cosmos and everything within it.

_Opening of Philolaus's treatise on natural philosophy._

## Links

- HTML: https://www.betterreads.online/discover/the_lives_and_opinions_of_eminent_philosophers_se/chapters/philolaus
- Book: https://www.betterreads.online/discover/the_lives_and_opinions_of_eminent_philosophers_se
- All chapters: https://www.betterreads.online/discover/the_lives_and_opinions_of_eminent_philosophers_se/chapters