It’s hard to overestimate Alan Turing’s contributions to contemporary civilization. To mathematics, he contributed one of two nearly simultaneous proofs about the limits of first-order logic. In cryptography he devised an electromechanical device that decoded German Enigma machine’s signals during World War II, an accomplishment that should also be counted as a contribution to twentieth century warfare and politics. In computer science, he developed a theory of universal computation and an associated architectural design that forms the foundation for the computer on which you are now reading. His take on machine intelligence has been influential in both the philosophy of mind and as the foundation of the field of artificial intelligence. And his prosecution for homosexuality, along with his apparent resulting suicide has offered a pertinent reminder of one of the remaining barriers to social justice and equity.