It was Alan Turning’s (1912-1954)1 birthday on June 23rd. Many people may not have heard of him, but owing to the cult of celebrity they will know of Benedict Cumberbatch, who portrayed him in the movie ‘The Imitation Game’2. Turing was one of the most influential theoretical computer scientists of the 20thcentury. In 1936, he published a paper entitled ‘On computable numbers, with an application to the Entsheidungsproblem’. While the German word may be obscure to almost everyone, it simply means ‘decision problem’ which was first posed by German mathematician David Hilbert in 19281. In this paper, Turing provides three proofs, all of which are beyond my mathematical understanding. Suffice it to say, that they are all dependent on the development of a typewriter-like computing machine3; and that is precisely the type of device on which this article is being typed.
Turing was recruited to work at the Government Code and Cypher School at Bletchley Park. This was Britain’s codebreaking centre during the Second World War. He made improvements on the Polish electromechanical ‘bombe’ method that could determine the settings for the German coding device, the Enigma machine4. The cracking of the Enigma code allowed the Allies to read high level German signals traffic and gave them an insight into German plans and tactics and enabled the Allies to defeat the Germans in many pivotal battles and campaigns, not least of which was the Battle of the Atlantic. It has been estimated that it could have shortened the war by as much as two years and saved over fourteen million lives.
After the war, Turing worked at the National Physical Laboratory, where he designed one of the first stored-program computers. He also worked at the Victoria University of Manchester where he helped to develop the stored-program Manchester Computers. In 1952 he was prosecuted for homosexual acts under the Labouchere Amendment to the Criminal Law Amendment Act 1885, which made ‘gross indecency’ a criminal offence1. This was the same law under which Oscar Wilde was convicted5. As an alternative to prison, Turing was sentenced to chemical castration by oestrogen injections5.
Turing died in 1954, 16 days short of his 42nd birthday. The inquest into his death concluded that it was suicide and that a half-eaten apple by his body had been the method for the administration of the fatal dose of cyanide. Unfortunately, the apple was never tested for cyanide. Although other theories have been put forward that suggest his death was an accident, these have little evidence to support them1.
The irony is that Turing felt forced to commit suicide by the legalised bigotry of the country he helped save from defeat, and its many thousands of compatriots whose lives he helped save. There are people out there, and in politics, who want to recriminalise homosexuality, and who want to make it legal to discriminate against homosexuals again. They want that injustice, that hatred, that murderous bigotry, to begin again. We cannot ever let them.