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Alan Turing

British mathematician, logician, cryptanalyst, and computer scientist
A statue of Alan Turing
A rebuild of a machine made by Alan Turing

Alan Mathison Turing OBE FRS (London, 23 June 1912 – Wilmslow, Cheshire, 7 June 1954) was an English mathematician and computer scientist. He was born in Maida Vale, London.[1]


Early life and familyEdit

Alan Turing was born in Maida Vale, London on 23 June 1912. His father was part of a family of merchants from Scotland. His mother, Ethel Sara, was the daughter of an engineer.


Turing went to St. Michael's, a school at 20 Charles Road, St Leonards-on-sea, when he was five years old.


Turing was one of the people who worked on the first computers. He was the first person to think of using a computer to do things that were too hard for a person to do. He created the Turing machine in 1936. The machine was imaginary, but it included the idea of a computer program.

Turing was interested in artificial intelligence. He proposed the Turing test, to say when a machine could be called "intelligent". A computer could be said to "think" if a human talking with it could not tell it was a machine.[2]

During World War II, Turing worked to break German ciphers (secret messages). Using cryptanalysis, he helped to break the codes of the Enigma machine. After that, he solved other German codes.

From 1945 to 1947, Turing worked on the design of the ACE (Automatic Computing Engine) at the National Physical Laboratory. He presented a paper on 19 February 1946. That paper was "the first detailed design of a stored-program computer".[3] Although it was possible to build ACE, there were delays in starting the project. In late 1947 he returned to Cambridge for a sabbatical year. While he was at Cambridge, the Pilot ACE was built without him. It ran its first program on 10 May 1950.

Private lifeEdit

Turing was a homosexual man. In 1952, he admitted having had sex with a man in England. At that time, homosexual acts were illegal. Turing was convicted. He had to choose between going to jail and taking hormones to lower his sex drive. He decided to take the hormones.[4] After his punishment, he became impotent. He also grew breasts.[5]

In May 2012, a private member's bill was put before the House of Lords to grant Turing a statutory pardon.[6] In July 2013, the government supported it.[7] A royal pardon was granted on 24 December 2013.[8][9]


In 1954, Turing died from cyanide poisoning. The cyanide came from either an apple which was poisoned with cyanide, or from water that had cyanide in it. The reason for the confusion is that the police never tested the apple for cyanide.[10] It is also suspected that he committed suicide.

The treatment forced on him is now believed to be very wrong. It is against medical ethics and international laws of human rights. In August 2009, a petition asking the British Government to apologise to Turing for punishing him for being a homosexual was started.[11][12] The petition received thousands of signatures.[13] Prime Minister Gordon Brown acknowledged the petition. He called Turing's treatment "appalling".[14]


  1. Newman M.H.A. 1955. Alan Mathison Turing. 1912–1954. Biographical Memoirs of Fellows of the Royal Society 1: 253. [1]
  2. Harnad, Stevan 2008. The Annotation game: Turing (1950) on Computing, machinery and intelligence. In: Epstein, Robert & Peters, Grace (eds) Parsing the Turing Test: philosophical and methodological issues in the quest for the thinking computer. Springer
  3. Copeland, B. Jack 2006. Colossus: The secrets of Bletchley Park's code-breaking computers. Oxford University Press. p108 ISBN 978-0-19-284055-4
  4. Turing, Alan (1952). "Letters of Note: Yours in distress, Alan". Archived from the original on December 16, 2012.
  5. Andrew Hodges (2012). Alan Turing: The Enigma The Centenary Edition. Princeton University.
  6. "Parliamentary bill launched for Alan Turing pardon". The Guardian. Retrieved 25 July 2012.
  7. Nicholas Watt (19 July 2013). "Enigma codebreaker Alan Turing to be given posthumous pardon". The Guardian.
  8. Oliver Wright (23 December 2013). "Alan Turing gets his royal pardon for 'gross indecency' – 61 years after he poisoned himself". The Independent.
  9. "(Archived copy of) Royal Pardon for Alan Turing" (PDF).
  10. Hodges, Andrew 1983. Alan Turing: the enigma. London: Burnett Books, p488. ISBN 0-04-510060-8
  11. Thousands call for Turing apology. BBC News. 31 August 2009. Retrieved 31 August 2009.
  12. Petition seeks apology for Enigma code-breaker Turing. CNN. 1 September 2009. Retrieved 1 September 2009.
  13. The petition was only open to UK citizens.
  14. "PM's apology to codebreaker Alan Turing: we were inhumane". The Guardian. 11 September 2009.

Other websitesEdit

  • Jack Copeland 2012. Alan Turing: The codebreaker who saved 'millions of lives'. BBC News / Technology [2]