He characterized all existing entities by pairs of contrary properties  This is most famously expressed with his claim "Mortals are immortals and immortals are mortals, the one living the others' death and dying the others' life". This is taken to mean men are mortal gods, and gods immortal men. He would also point out that sleep is like death. He was fond of speaking this way. He also said "Man kindles a light for himself in the night-time, when he has died but is alive. The sleeper, whose vision has been put out, lights up from the dead; he that is awake lights up from the sleeping," and "All the things we see when awake are death, even as all we see in slumber are sleep." In this union of opposites, of both generation and destruction, Heraclitus called the oppositional processes (), "strife", and hypothesizes that the apparently stable state, (), or "justice", is a harmony of it. Anaximander described the same as injustice. Aristotle mentions that Heraclitus disliked Homer because he wished strife would leave the world, which for Heraclitus would destroy the world; "there would be no harmony without high and low notes, and no animals without male and female, which are opposites." Heraclitus is the original philosopher to claim that war is a good thing. He also wrote "Every beast is driven to pasture by blows." We must know that war is common to all and strife is justice, and that all things come into being through strife necessarily. Gods and men honor those who are slain in battle. The people must fight for its law as for its walls. In a metaphor and one of the earliest uses of a force in the history of philosophy, Heraclitus compares the union of opposites to a strung bow or lyre held in shape by an equilibrium of the string tension:There is a harmony in the bending back ( "palintropos") as in the case of the bow and the lyre. He claims this shows something true yet invisible about reality; "a hidden harmony is better than an apparent one." He also noted "the bow's name is life, though its work is death," a play on both bow and life being the same word as written – biós; further evidence of a continuous, written work. On the unity of opposites, Burnet says:"The " strife of opposites " is really an “ attunement ” (armonia).