September 1 of this year marked the 70th anniversary of Nazi Germany’s invasion of Poland, the point of no return for the beginning of World War II. It is in some sense fitting that this month also sees the issuance of an official apology from UK Prime Minister Gordon Brown for the treatment of the British mathematician and pioneer computer scientist, Alan Turing. It is not easy to argue that the actions of any single person, no matter how heroic they were on an individual basis, potentially changed the course of an event as enormous as World War II, but in Turing’s case there is a fair argument to be made. His work in breaking the encipherment of the German Enigma machines (there were several variants), building on the work of Polish mathematicians, and his contributions to the design of the bombes, electro-mechanical computers used to crack Enigma messages on a production basis, made an enormous contribution to the defeat of Nazi Germany. Some historians estimate that the penetration of the Nazis’ secret communications shortened the European war by two years. As Prime Minister Gordon Brown put it:
Turing was a quite brilliant mathematician, most famous for his work on breaking the German Enigma codes. It is no exaggeration to say that, without his outstanding contribution, the history of World War Two could well have been very different. He truly was one of those individuals we can point to whose unique contribution helped to turn the tide of war.
Turing, who was named one of Time magazine’s 100 Most Important People of the [20th] Century, would have been an important figure even if the war had never occurred. He studied at King’s College, Cambridge, receiving a first-class honours degree, and being elected a Fellow on the basis of his thesis on the Central Limit Theorem. In 1936, he published a landmark paper, On Computable Numbers, with an Application to the Entscheidungsproblem, in which he analysed a reformulation of Kurt Gödel’s results of the limits of mathematical proof, and described a theoretical computing machine to illustrate the result. The Turing machine, as a conceptual device, is a staple of computer science today. Shortly before the war, he studied in the United States at Princeton University and the Institute for Advanced Study, receiving his PhD from Princeton in 1938. Turing also made significant contributions to early theoretical work on artificial intelligence, particularly the Turing Test.
Turing would undoubtedly have made many more contributions, but he had a severe handicap: he was gay, in an era when homosexuality could hardly be discussed. In 1952, in an atmosphere in Britain not that different from the McCarthy era in the US, Turing was prosecuted and convicted of gross indecency for a sexual relationship with another man. He was sentenced to forcible injections of female hormones, a procedure known as chemical castration. Turing died, apparently from suicide, in June 1954 at age 41. To quote PM Brown once again:
The debt of gratitude he is owed makes it all the more horrifying, therefore, that he was treated so inhumanely. In 1952, he was convicted of ‘gross indecency’ – in effect, tried for being gay.
So on behalf of the British government, and all those who live freely thanks to Alan’s work I am very proud to say: we’re sorry, you deserved so much better.
Andrew Hodges, author of the biography Alan Turing: The Enigma, maintains a Web site dedicated to Turing.
Update, Friday, 11 Sept., 20:50
The Atlantic Web site has a short article by Andrew Sullivan on this.
Update, Sunday, 13 Sept., 22:05
USA Today had an article on the apology. You can listen to a brief report from National Public Radio at the WBUR (Boston) Web site.