Democritus

c. 460 - c. 370 BCE · Greek (Ionian, of Abdera in Thrace) · Presocratic atomist physics, cosmology, epistemology, ethics

By convention sweet, by convention bitter; but in reality atoms and void.

Democritus traveled further than almost any philosopher of antiquity — Egypt, Persia, possibly India — yet is remembered for saying he visited Athens and no one recognized him. He worked from Abdera, a small Thracian city, with his teacher Leucippus, on a question that would define two millennia of argument: what is the world made of?

Topics Democritus addresses

• atoms and void
• atoms as indivisible and eternal
• the void as what is not
• infinite variety of atomic shapes and sizes
• the nomos/physis distinction
• by convention sweet, by convention bitter
• secondary qualities as conventional
• primary atomic properties
• genuine vs bastard knowledge
• the wretched mind dialogue
• truth is in the depths
• the eidola theory of sensation
• euthymia
• cheerful self-sufficiency
• the cosmic swirl
• innumerable worlds
• mechanical cosmogony
• necessity and chance
• nothing happens in vain
• anti-teleology
• the atomic theory of soul
• response to Parmenidean monism
• the joint Leucippus-Democritus project
• anti-creationism

Converse with Democritus on Symposium. Every reply is grounded in Democritus's own writing and cites the page it came from. The corpus is public-domain text.