Kernel
Turing is the figure who turns mathematical logic into the substrate of an industrial civilization. "On Computable Numbers" (1936) defines the universal Turing machine. The Bletchley Park work (1939–45) breaks Enigma and shortens World War II by, per a common estimate, two to four years and millions of deaths. The 1950 "Computing Machinery and Intelligence" paper poses the question still being argued in every AI lab in 2026.
Contribution
The universal computing machine — the abstract framework that every modern processor instantiates. The decision-problem proof (1936) that bounds what computation can do. The Bombe (the electromechanical Enigma-breaker). The Turing Test. The foundational paper of theoretical computer science.
Lineage
Cambridge under Hardy; Princeton under Church; Bletchley Park under Bletchley. Influenced by Gödel's incompleteness. Influences von Neumann directly (von Neumann's 1945 EDVAC report explicitly cites Turing's universal-machine construction).
Civilization-scale significance
The civilizational figure of computation. His prosecution and chemical castration for homosexuality (1952) and probable suicide (1954) became, half a century later, the moral test case the British government failed and then formally apologized for.