Alan Turing saved my life.
In early September 1940, when bombing industrial sites alone seemed inconclusive, the German Luftwaffe began round-the-clock bombing of British civilian targets, particularly London and other key cities. These included Liverpool, a major industrial port, where I would be born in late October of that year during the most intense part of what the British called "the Blitz" -- when target cities were bombed for 57 straight nights. (Bombing would continue for eight months more, though never as sustained as in those first two months.)
On Liverpool's Royal Infirmary, a hospital in ruins, the bombs fell pitilessly. A flapping tarpaulin was all that protected my young mother in labor from bombs and the cold night outside. Anesthesia was reserved for the war wounded only. German U-boats (submarines) had utterly disrupted transatlantic food shipments, so as a newborn, I was soon in danger of starving.
Yet even as my birth took place, a brilliant young Cambridge don, recruited a few years earlier in deepest secrecy, was feverishly at work. He was Alan Turing, working in Hut 8 at Bletchley Park, a former Buckinghamshire estate of mixed architectural styles -- Victorian Gothic, Tudor, Dutch Baroque -- that had been converted to a wartime research installation, devoted to cracking the German codes.
His luminous intelligence and the brilliance of his team (some of them recruited in a competition to see who could finish a newspaper crossword puzzle the fastest) allowed the British to begin secretly to decrypt signals from the Enigma and Lorenz machines, used for communication between German war headquarters and deployed U-boats, and land an airborne forces.
"I won't say that what Turing did made us win the war," his statistical clerk, Jack Good, told me later, as I was researching a book that would be the first history of artificial intelligence, called Machines Who Think, "but I daresay we might have lost it without him."
I interviewed Good in the mid-1970s, when the Official Secrets Act still silenced many. Only decades later were Turing's associates, and then, historians of computing, mathematics, and cryptography, able to reveal in detail how crucial Turing's contribution had been to the war effort, to the ultimate Allied victory, and to hungry babies like me, born into what then looked like a losing effort.
A man who had saved his country was hounded to death by it.
My first acquaintance with Turing was related to my research in the history of AI. His work in the field was groundbreaking -- and emerged soon after he was able to lay down his wartime responsibilities.
During a sabbatical at his old school, King's College, Cambridge, he wrote a paper in September 1948 called "Intelligent Machinery." Unpublished for almost two decades, its intellectual penetration is startling even today. In it he proposed the possibility of machine intelligence, beginning with arguments against the idea: that humans will not admit the possibility of rivals in intellectual power; that such a machine, if possible, would be irreverent; that machinery and humans are vastly different; that Gödel's Theorem shows that machines are inherently incapable of solving problems which humans can overcome; and that, anyway, machine intelligence is no more than a reflection of the intelligence of its creator. And then he refuted each one -- brilliantly.
More famously, in October 1950 he published "Computing Machinery and Intelligence," in which he proposed what came to be known as the Turing Test, consisting of an interrogation between a human judge and hidden respondents -- the human judge to decide whether the respondents were human or machine. The paper caused a scientific sensation, and eminent critics rose hotly to defend human intelligence. Turing responded in written and oral debate with great coolness, élan, and humor.
By now Turing had conducted some experiments that informed his arguments. He'd designed one of the first ever chess-playing programs (for a machine that didn't yet exist) and he was growing interested in the operations of the human brain, which might, he hoped, give him deeper insights into how to construct a thinking machine.
But he was also homosexual, which in his time in England was a punishable offense. A brief liaison in January 1952 with a common criminal brought this to light, and both he and the other man were charged with gross indecency.
Convicted, Turing had to choose between prison, or "chemical castration," injections of estrogen, then thought to kill the homosexual libido. He accepted chemical castration; his conviction and punishment were public, degrading, and lost him his security clearance.
He was found dead of cyanide poisoning on June 8, 1954, his death ruled a suicide, though Turing's mother protested that it was accidental, and the consequence of her son's carelessness with laboratory materials. He was 42 years old.
Turing's homosexuality, and the tragic circumstances of his death, were known and spoken of among the people I interviewed for my book, but several of his colleagues were dismayed that I would say it in print. For me, who owed my very life to Turing's work, this petty delicacy was unconscionable.
A man who had saved his country had been hounded to death by it.
* * *
Three years after Turing's death, the Wolfenden Report was published in 1957, recommending that homosexuality be decriminalized in the U.K., though it took another ten years to change the law. Honors were eventually heaped upon Alan Turing's shade: the highest award in computer science is the Turing Prize; plaques appear on buildings where he lived and worked, a road is named for him. Two biographies have appeared, a play, and at least two films. In 2009, Gordon Brown, on behalf of the British government, formally apologized for its treatment of Turing, "one of those individuals ... whose unique contribution helped to turn the tide of war." On the 100th anniversary of his birth, elaborate tributes and celebrations have been held in San Francisco, London, Cambridge, and Manchester.
Of course we will never know what Turing might have contributed to human knowledge if allowed to live out his natural life, surely our very great loss. This is the cost of human bigotry.