George Price’s letter to William Hamilton


George R. Price (1922-1975) was an American physical chemist turned evolutionary biologist who is best known for deriving the Price equation - a mathematical explanation for the genetic basis of altruistic behavior.

Price had come to London in 1968 pursuing a disparate range of research interests. Whilst in a library he came across evolutionary biologist W.D. Hamilton’s famous kin selection paper The Genetical Evolution of Social Behaviour (1964) the implications of which - that true altruism is dependent on the level of genetic relatedness between individuals - so shocked him that he set out to disprove it. As he recounts in this letter to Hamilton ‘What happened was that – to my surprise – I did not derive the same expressions you obtained … On further studying the mathematics, I found that I had a surprisingly simple equation for gene frequency change under selection’. Price’s equation meant that altruistic behavior, along with any other trait, could be calculated by association between individuals and was not dependent simply upon their genetic relatedness.

Upon showing his equation to Cedric Smith a ‘mathematical geneticist’ at the Galton Laboratory, University College London, Price was given an office and an honorary appointment. He later worked with evolutionary biologist John Maynard Smith co-authoring a paper which introduced Evolutionarily Stable Strategy and was also responsible for formalizing statistician R. A. Fisher's fundamental theorem of natural selection. However, burdened by the social implications of his equation, Price veered from atheism to fundamental Christianity whilst giving away most of his possessions to the homeless; becoming homeless himself in the process. He committed suicide in 1975.

Full title:
Letter (2 ff), carbon copy typescript, from George Price to W D Hamilton
George R Price
© Estate of George Price
Add MS 84116

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