Heraclitus was an aristocrat of Ephesus famous for his enigmatic style, which earned him the nickname The Obscure. He taught that everything is in constant change and that the conflict between opposites keeps the world in balance. His short, provocative fragments inspired everyone from the Stoics to Hegel and Nietzsche.
Core ideas
Everything flows: reality is in permanent transformation
Opposites are united, and the tension between them creates the order of the world
There is a universal reason, the logos, that governs all things
The tradition: Presocratic
The Presocratics are the first Greek philosophers, before Socrates, who tried to explain nature without relying only on myths. Heraclitus is one of the most original of the group.