J.B.S. Haldane

J.B.S. Haldane (John Burdon Sanderson Haldane, 1892–1964) was a British-Indian geneticist and evolutionary biologist who, with R.A. Fisher and Sewall Wright, founded modern theoretical population genetics. His 1924–1934 series of papers, A Mathematical Theory of Natural and Artificial Selection, established the quantitative framework for how natural selection changes allele frequencies over time — work that was indispensable to the Modern Synthesis.

Haldane calculated selection coefficients for real genetic systems and estimated the time required for natural selection to produce observed evolutionary changes. His estimate of the cost of natural selection — the genetic deaths required to fix a single beneficial mutation — later became the launching point for Motoo Kimura's neutral theory.

Beyond genetics, Haldane was a committed Marxist who spent years defending Lysenkoism before recanting, a pioneer of self-experimentation (he tested decompression sickness on himself), and the author of the observation that the universe is not only queerer than we suppose, but queerer than we can suppose — a sentiment that reflects his broader view that reality routinely outpaces the theoretical frameworks built to contain it.