The School of Athens (detail: Heraclitus, in the image of Michelangelo), 1509. Sanzio Raffaello (Italian, 1483-1520). Fresco. Stanza della Segnatura, Palazzi Pontifici, Vatican.
Heraclitus taught that “everything flows” or “everything is in flux,” the closest element to this flux being fire; he also extended the teaching that seeming opposites in fact are manifestations of a common substrate to good and evil itself.