PERSON
W.D. Hamilton
The evolutionary biologist who reduced altruism to an inequality, turned cooperation among the selfish into a derived result rather than a moral wish, and gave the AI alignment problem its clearest biological mirror—the question of when self-interested optimizers will help rather than defect, and why the answer depends on structure rather than sentiment.
William Donald Hamilton was, by the estimate of those best placed to judge, the most consequential evolutionary theorist since Darwin. He took the softest subject in biology—love, sacrifice, the willingness of one creature to spend itself for another—and reduced it to a single inequality that any child could read and no one had written before: a gene for helping spreads when
rB > C, when the relatedness of helper to helped, multiplied by the benefit the help confers, exceeds the cost to the helper. Altruism among the selfish is not a paradox to be explained away but a prediction to be derived. From this foundation Hamilton mapped a world in which apparent benevolence and apparent malice are both bookkeeping at the level of the replicator: the gene’s-eye view, later made famous by
Richard Dawkins, which Hamilton’s mathematics made possible. His work extended from