"War is one of the constants of history, and has not diminished with civilization or democracy. In the past 3,421 years of recorded history on 268 have seen no war. We have acknowledged war as at present the ultimate form of competition and natural selection in the human species. 'Polemos pater panton,' said Heracleitus; war, or competition, is the father of all things, the potent source of ideas, inventions, institutions, and states. Peace is an unstable equilibrium, which can be preserved only by acknowledged supremacy or equal power."
-Will and Ariel Durant, The Lessons of History, 1968