Anaxagoras: The Presocratic Who Dared to Say the Sun Was a Stone

Anaxagoras, a pre-Socratic Greek philosopher born in Clazomenae (then part of the Persian Empire), challenged mythological explanations of the cosmos by proposing natural principles. He introduced the concept of Nous, an infinite, unmixed rational force that initiates cosmic motion and order. Anaxagoras argued the universe began as a chaotic mixture of infinite particles ("seeds"), set into rotation by Nous, leading to differentiation and the formation of distinct objects—a process he saw as ongoing. He famously claimed the sun was a burning stone, not a god, leading to his trial for heresy in Athens after 30 years. His pupil Pericles helped him escape; he fled to Lampsacus and founded a school. Anaxagoras opposed Parmenides' monism, advocating a pluralistic reality with real change and motion. He never married, gave up his inheritance to pursue philosophy, and is credited with sparking Athens' philosophical golden age. His last wish—that the month of his death be a holiday for students—was honored, per Diogenes Laërtius.