He was the greatest biologist of the 20th century yet, to the dismay of his many friends and admirers, he believed that only a radical programme of infanticide and eugenics could save the human raceby Andrew Brown / January 20, 2003 / Leave a comment
Published in January 2003 issue of Prospect Magazine
No one was quite sure what killed Bill Hamilton in March 2000, but it was widely supposed that he had died of malaria, contracted on an expedition to sample chimpanzee faeces in the Congo. What everyone knew for certain was that with his passing had gone the greatest evolutionary thinker of the late 20th century. Richard Dawkins certainly thought so. In a moving and delicate eulogy, he said that meeting Hamilton was the closest a modern biologist could come to meeting Darwin.
In his famous book The Selfish Gene, first published in 1976, Dawkins had produced a thrilling synthesis of the three key 20th century developments in Darwinian thought: genetics, ethology (the study of animal behaviour) and game theory. But the most original aspect of the book derived from the work of Hamilton. It explained how ruthless competition between genes could produce selfless co-operation in the organisms that carry them. “Biological altruism” is the quality which explains why bees sting in defence of their hives, even though it kills them to do so. This puzzled the young Hamilton, as it had puzzled Darwin. Bees that kill themselves must leave fewer descendants than those which hang back, so if a tendency to self-sacrifice is inherited, it would surely vanish in competition with tendencies to more selfish behaviour. But this kind of co-operation has not vanished. On the contrary, in some species, it has increased. So, over countless generations, the more altruistic bees must have outcompeted the selfish ones, something that seems to entail a contradiction in Darwinian logic. The central insight of selfish gene theory dissolves this apparent contradiction: it holds that altruistic behaviour of this sort will spread and increase if it benefits relatives of the altruist, who are also likely to carry the altruistic gene and thus to leave descendants who will in turn sacrifice themselves for their relatives, and so on. The gene for altruistic behaviour in bees competes for survival with a gene for more selfish behaviour. The result of this “strategic” competition between bee genes can be co-operation among bees. As a graduate student, working in obscurity, Hamilton had formulated and made mathematically rigorous this idea of “inclusive fitness.” In some ways, it resembled Adam Smith’s invisible hand, but Hamilton’s formula was more precisely defined than the economic version.