Heraclitus of Ephesos (535 BC - 475 BC)

Heraclitus holds apparently contradictory principles: everything is constantly changing, opposite entities are identical, and everything is and is not at the same time. The cosmos functions on the basis of a law-like flux of elements and the transformational equivalence of opposites. The first to go beyond physical theory in order to find out metaphysical foundations and ethical applications, Heraclitus shows that reality changes according to a universal law that functions as a moral law for human beings. Man is regarded as a voluntary agent whose awareness of the nature of reality and human condition can determine him to take morally correct actions.