It is the key to understanding half the altruistic cooperation in nature. The great obsession of his later career was parasites - their evolutionary rather than their medical impact. Over twenty years, Hamilton convinced more and more biologists that parasites are the key to many outstanding problems left by Darwin, including the baffling riddle of the evolution of sex. The sexual shuffling of the genetic pack is an elaborate trick for outrunning parasites in the endless race through evolutionary time. This work led Hamilton into the arcane world of computer simulation, where his models were as richly textured, in their way, as his beloved Brazilian jungle.
Male advertisement is an honest boast of health.
Would that every mathematical lump were leavened, as Hamilton's were, by eye-witness accounts of, say, the male mite who copulates with all his sisters and then dies before any of them are born. Or of aphid females who give live birth to their daughters and granddaughters simultaneously. For most scientists, good ideas are a scarce commodity, to be milked for everything they are worth. Hamilton, by contrast, would bury, in little throwaway asides, ideas for which others would kill. Sometimes he buried them so deeply that he overlooked them himself.