Flux

Flux is the doctrine associated with Heraclitus of Ephesus (c. 500 BCE): all things are perpetually changing, and stability is only the appearance of a deeper, ever-shifting process unified by an underlying logos (order/reason). His river image — the waters always different though the river endures — became the emblem of becoming over being. The idea provoked Parmenides' opposite insistence on changeless being, and through Plato, who pushed the river to its extreme, it shaped the central Greek debate over permanence and change.