Heraclitus, of Ephesus

Heraclitus (; Ancient Greek: Ἡράκλειτος, romanized: Hērákleitos; fl. c. 500 BC) was a pre-Socratic Greek philosopher from the city of Ephesus, which was then part of the Persian Empire. He exerts a wide influence on Western philosophy, both ancient and modern, through the works of such authors as Plato, Aristotle, the Stoics, Georg Wilhelm Friedrich Hegel, Friedrich Nietzsche, and Martin Heidegger. Little is known of Heraclitus's life. He wrote a single work, of which only fragments survive. Even in ancient times, 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 atomist philosopher Democritus, who was known as "the laughing philosopher". The central ideas of Heraclitus's philosophy are the unity of opposites and the concept of change. Heraclitus 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 ῥεῖ, 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 element of the world. In choosing an arche Heraclitus followed the Milesians before him — Thales of Miletus with water, Anaximander with apeiron ("boundless" or "infinite"), and Anaximenes of Miletus with air. Heraclitus also thought the logos (lit. word, discourse, or reason) gave structure to the world or existed as a kind of divine law.