Box Turtle Bulletin

Born On This Day, 1912: Alan Turing

(d. 1954) It’s hard to imagine what the 21st century would have looked like without him. The English mathematician, logician, and cryptanalyst practically invented computer science when he formalized the idea of “algorithm” and “computation” with the what became known as the Turing machine. It was a conceptual device, which he imagined to consist of an infinitely long tape which would be capable of writing, reading and changing arbitrary symbols, much as a hard drive can do so today. With that concept defined, he proved that relatively simple Turing machines would be capable of making computations — hence the very term computer that we use today.

A working replica of a Turing Bombe on display at Bletchley Park (Click to enlarge)

Turing became a Fellow at King’s College at Cambridge just four years after entering as an undergrad. He earned his Ph.D. at Princeton in just two years, just in time to head home to Britain before World War II. After a brief stint at Cambridge, he joined the famous Government Code and Cypher School at Bletchley Park, where he headed the section responsible for German naval cryptanalysis. He devised a number of techniques for breaking German ciphers, the most important of which was the bombe, an electromechanical machine that could determine the settings for Germany’s “unbreakable” Enigma machine. Turing’s bombes were instrumental in Germany’s ultimate defeat when the Enigma code was cracked.

Following the war, Turing worked at the National Physical Lab (NPL) in London on the design of the Automatic Computing Engine (ACE). In 1946, he presented the design for the first stored-program computer. But because his work at Bletchley Park was classified, he found it difficult to translate what he invented there to the NPL. He left NPL in frustration and returned to academia at the University of Manchester, where he devised what is now known as the Turing Test. The Turing Test still serves as a standard for whether a computer could be considered “intelligent.” The test was simple: a computer could be considered a “thinking machine” if a human, through ordinary conversation, could not tell its responses apart from those of another human being. He then set about writing a program to play chess, but he was stymied by the lack of computers powerful enough to execute it.

Turing’s life took a dramatic turn in 1952 when he met Arnold Murray outside a Manchester theater and asked him for a lunch date. After a few weeks, the man spent the night at Turing’s house. Sometime later, Murray stole a gold watch and some other items from Turing’s home. Turing reported the crime to police. When police investigated, they asked Turing how he knew Murray. Turing, who had become somewhat open about his homosexuality by that time, acknowledged the sexual relationship.

But with homosexuality being illegal in England, Turing was charged with gross indecency, the same crime for which Oscar Wilde was convicted more than half a century earlier. Turing was given a choice between imprisonment or probation on the condition he underwent chemical castration via estrogen hormone injections. Turing chose the latter, but his conviction led to his security clearance being revoked, which seriously damage both his career and reputation. And as the Red Scare rose its ugly head in the early 1950s, and with gay men coming under growing suspicion for being a danger to national security, Turing found himself under increasing surveillance. His estrogen injections themselves may have added to his feelings of hopelessness; one of the side effects of the synthetic estrogen he was prescribed was depression. Finally on June 7, 1954, Turing’s cleaning woman found him dead in his bedroom with a half-eaten apple laying beside his bed. An autopsy revealed that he died of cyanide poisoning. That apple was never tested for cyanide, but it is believed that this was how he ingested the fatal dose.

After the secrets of Bletchley Park were declassified, Turing’s posthumous reputation as a war hero only added to growing recognition of his impressive contributions to computer science. In 1966, the Association for Computing Machinery (ACM) began awarding the Turing Prize for outstanding technical contributions to computing. His childhood home in London has been designated a English Heritage site with an official Blue Plaque. Another Blue Plaque was placed at his home in Wilmslow where he died, and today a third will be unveiled in front of King’s College at Cambridge. In 2009, Prime Minister Gordon Brown formally apologized: “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.”

A petition to have Turing formally pardoned was circulated 2012 as part of the observance of Turing’s centenary. But the request was denied by Justice Minister Lord McNally, saying: “A posthumous pardon was not considered appropriate as Alan Turing was properly convicted of what at the time was a criminal offence. He would have known that his offence was against the law and that he would be prosecuted.” McNally added that the best response would be to “ensure instead that we never again return to those times.” Turing finally got a Royal pardon on Christmas eve of 2013 after a request from Justice Minister Chris Grayling. Benedict Cumberbatch, who portrayed Turing in the 2014 biopic The Imitation Game, has joined Stephen Fry, producer Harvey Weinstein, and Turing’s great niece Rachel Barnes in a campaign to pardon the 49,000 who had been convicted under the anti-gay law.