"In... Heraclitus... Becoming occupies the foremost place. He regarded that which moves, the fire, as the basic element. The difficulty, to reconcile the... one fundamental principle with the infinite variety of phenomena, is solved... by recognizing... strife of... opposites is... a kind of harmony. ...[T]he world is ...one and many ..."the opposite tension" of ...opposites ...constitutes the unity of the One. He says: "...war is common to all and strife is justice ...all things come into being and pass away through strife." ...[T]hat infinite and eternal undifferentiated Being ...cannot ...explain the infinite variety of things. This leads to the antithesis of Being and Becoming and ...to the solution of Heraclitus ...change ...is the fundamental principle; the "imperishable change, that renovates the world," as the poets have called it. But ...change ...is not a material cause and therefore is represented ...by the fire ...both matter and a moving force. ...[[Physics|[P]hysics]] is ...extremely near to ...Heraclitus ...[i]f we replace ..."fire" by ..."energy" ...Energy is a substance, since its total ...does not change, and ...elementary particles can ...be made from this ...Energy may be called the fundamental cause for all change in the world. ...Energy is ...that which moves; it may be called the primary cause of all change, and ...can be transformed into matter or heat or light. The strife between opposites in the philosophy of Heraclitus can be found in the strife between two different forms of energy."