Heraclitus

Little is known of Heraclitus's life. He wrote a single work, only fragments of which have survived, catalogued under philosopher number 22 in the Diels–Kranz numbering system. Already in antiquity, his paradoxical philosophy, appreciation for wordplay, and cryptic, oracular epigrams earned him the epithets "the dark" and "the obscure". He was considered arrogant and depressed, a misanthrope who was subject to melancholia. Consequently, he became known as "the weeping philosopher" in contrast to the ancient philosopher Democritus, who was known as "the laughing philosopher".


The central ideas of Heraclitus' philosophy are the unity of opposites and the concept of change. He also saw harmony and justice in strife. He viewed the world as constantly in flux, always "becoming" but never "being". He expressed this in sayings like "Everything flows" (Greek: πάντα ρει, panta rhei) and "No man ever steps in the same river twice". This insistence upon change contrasts with that of the ancient philosopher Parmenides, who believed in a reality of static "being".


Heraclitus believed fire was the arche, the fundamental stuff of the world. In choosing an arche Heraclitus followed the Milesians before him – Thales with water, Anaximander with apeiron (lit. boundless or infinite), and Anaximenes with air. Heraclitus also thought the logos (lit. word, discourse, or reason) gave structure to the world.