The Price equation was not, as Price had hinted to him, a new derivation or correction of his ideas. Instead, it was “a strange new formalism that was applicabl

The Price equation was not, as Price had hinted to him, a new derivation or correction of his ideas. Instead, it was “a strange new formalism that was applicable to every kind of natural selection”. Its strangeness came precisely because Price was not a biologist – instead of starting from the work of their scientific forebears, he had worked everything out for himself from first principles. “In doing so,” wrote Hamilton, “he had found himself on a new road and amid startling landscapes.”