HERACLITUS (544-475 B.C.). Also called “the obscure.” Heraclitus lived in the commercial city of Ephesus in Asia Minor, and was one of the most eminent dialecticians of antiquity. According to him, becoming is the fundamental law of the universe; struggle and the interpenetration of opposites, the unity of being and non-being—such is the essence of the world. In this instability of everything, in the continual change of all being, Heraclitus saw the most general law of the universe. Everything flows, nothing is constant. As a result, “We cannot jump into the same river twice.” The universe is strife and peace, summer and winter, flux and rest, surplus and famine, etc. Contradiction, the dominant principle of the world, is, according to Heraclitus, inherent in all things, so that everything is an interpretation of opposites.