I, Robot - Pg 172

   "Every period of human development, Susan," said the Co-ordinator, "has had its own particular type of human conflict——its own variety of problem that, apparently, could be settled only by force. And each time, frustratingly enough, force never really settled the problem. Instead, it persisted through a series of conflicts, then vanished of itself,——what's the expression,——ah, yes 'not with a bang, but a whimper,' as the economic and social environment changed. And then, new problems, and a new series of wars. ——Apparently endlessly cyclic."