Alan Turing

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Alan Turing
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{{Redirect|Turing}}{{short description|British mathematician and computer scientist}}{{EngvarB|date=November 2017}}{{Use British English|date=November 2018}}{{Use dmy dates|date=November 2017}}

| image = Alan Turing Aged 16.jpg| caption = Turing {{circa}} 1928 at age 16| birth_name = Alan Mathison Turingdf=y6|23}}| birth_place = Maida Vale, London, United Kingdomdf=y6191223}}| death_place = Wilmslow, Cheshire, United Kingdom| resting_place = Ashes scattered in gardens of Woking Crematorium| death_cause = Suicide (disputed) by cyanide poisoning| residence = Wilmslow, Cheshire, United Kingdom Alonzo Church{{MathGenealogy>id=8014}}Robin Gandy,PHDTITLE=ON AXIOMATIC SYSTEMS IN MATHEMATICS AND THEORIES IN PHYSICSLAST=GANDYURL=HTTPS://WWW.REPOSITORY.CAM.AC.UK/HANDLE/1810/245090UK.BL.ETHOS.590164, doi=10.17863/CAM.16125}} {{free access}} Beatrice WorsleyJONATHAN P. >LAST=BOWEN CHAPTER=THE IMPACT OF ALAN TURING: FORMAL METHODS AND BEYOND EDITOR-FIRST1=JONATHAN P. EDITOR-FIRST2=ZHIMING EDITOR-LAST3=ZHANG TITLE=ENGINEERING TRUSTWORTHY SOFTWARE SYSTEMS. SETSS 2018 LECTURE NOTES IN COMPUTER SCIENCE > VOLUME=11430 DATE=2019 SPRINGER NATURE>SPRINGER DOI=10.1007/978-3-030-17601-3_5, Max NewmanIvor Grattan-Guinness>Grattan-Guinness, Ivor, Chapter 40, Turing's mentor, Max Newman. In JACK COPELAND>LAST1 = COPELAND AUTHORLINK2=JONATHAN BOWEN FIRST2=JONATHAN P. LAST3=WILSON LAST4=SPREVAK TITLE=THE TURING GUIDE OXFORD UNIVERSITY PRESS > YEAR=2017 TITLE-LINK = THE TURING GUIDE, | thesis_title = Systems of Logic Based on Ordinals| thesis_url =weblink| thesis_year = 1938| signature = Alan Turing signature.svg {edih}| prizes = Smith's Prize (1936)| partner = Joan Clarke(engaged in 1941; did not marry)}}Alan Mathison Turing {{postnominals|country=GBR|OBE|FRS}} ({{IPAc-en|ˈ|tj|ÊŠÉ™r|ɪ|Å‹}}; 23 June 1912 â€“ 7 June 1954) was an EnglishWEB, The British Library, Who was Alan Turing?, 29 July 2019,weblink mathematician, computer scientist, logician, cryptanalyst, philosopher and theoretical biologist.{{Who's Who | author=Anon| surname = Turing | othernames = Alan Mathison | id = U243891 | year = 2017 | doi = 10.1093/ww/9780199540884.013.U243891 | edition = online Oxford University Press|location=Oxford}} {{subscription required}} Turing was highly influential in the development of theoretical computer science, providing a formalisation of the concepts of algorithm and computation with the Turing machine, which can be considered a model of a general-purpose computer.NEWMAN > FIRST1 = M.H.A., Max Newman, 10.1098/rsbm.1955.0019, Alan Mathison Turing. 1912–1954, Biographical Memoirs of Fellows of the Royal Society, 1, 253–263, 1955, 769256, {{Harvnb|Sipser|2006|p=137}} Turing is widely considered to be the father of theoretical computer science and artificial intelligence.{{Harvnb|Beavers|2013|p=481}} Despite these accomplishments, he was not fully recognised in his home country during his lifetime, due to his homosexuality, and because much of his work was covered by the Official Secrets Act.During the Second World War, Turing worked for the Government Code and Cypher School (GC&CS) at Bletchley Park, Britain's codebreaking centre that produced Ultra intelligence. For a time he led Hut 8, the section that was responsible for German naval cryptanalysis. Here, he devised a number of techniques for speeding the breaking of German ciphers, including improvements to the pre-war Polish bombe method, an electromechanical machine that could find settings for the Enigma machine.Turing played a pivotal role in cracking intercepted coded messages that enabled the Allies to defeat the Nazis in many crucial engagements, including the Battle of the Atlantic, and in so doing helped win the war.A number of sources state that Winston Churchill said that Turing made the single biggest contribution to Allied victory in the war against Nazi Germany. However, both The Churchill Centre and Turing's biographer Andrew Hodges have said they know of no documentary evidence to support this claim nor of the date or context in which Churchill supposedly said it, and the Churchill Centre lists it among their Churchill 'Myths', see WEB,weblink Churchill Said Turing Made the Single Biggest Contribution to Allied Victory, Jonathan, Schilling, The Churchill Centre: Myths, 9 January 2015, and WEB,weblink Part 4: The Relay Race, Andrew, Hodges, Andrew Hodges, Update to (Alan Turing: The Enigma), 9 January 2015, A BBC News profile piece that repeated the Churchill claim has subsequently been amended to say there is no evidence for it. See NEWS,weblink Profile: Alan Turing, Clare, Spencer, BBC News, 11 September 2009, Update 13 February 2015, Due to the problems of counterfactual history, it's hard to estimate what effect Ultra intelligence had on the war,See for example BOOK, A Century of Spies: Intelligence in the Twentieth Century, Jeffery T., Richelson, Jeffrey T. Richelson, Oxford University Press, New York, 1997, 296, and BOOK, Guy, Hartcup, Guy Hartcup, The Effect of Science on the Second World War, Macmillan Press, Basingstoke, Hampshire, 2000, 96–99, but at the upper end it has been estimated that this work shortened the war in Europe by more than two years and saved over 14 million lives.NEWS, Copeland, Jack, Jack Copeland, Alan Turing: The codebreaker who saved 'millions of lives', 18 June 2012,weblink BBC News Technology, 26 October 2014, After the war, Turing worked at the National Physical Laboratory, where he designed the Automatic Computing Engine, which was one of the first designs for a stored-program computer. In 1948, Turing joined Max Newman's Computing Machine Laboratory at the Victoria University of Manchester, where he helped develop the Manchester computers{{Harvnb|Leavitt|2007|pp=231–233}} and became interested in mathematical biology. He wrote a paper on the chemical basis of morphogenesis and predicted oscillating chemical reactions such as the Belousov–Zhabotinsky reaction, first observed in the 1960s.Turing was prosecuted in 1952 for homosexual acts; the Labouchere Amendment of 1885 had mandated that "gross indecency" was a criminal offence in the UK. He accepted chemical castration treatment, with DES, as an alternative to prison. Turing died in 1954, 16 days before his 42nd birthday, from cyanide poisoning. An inquest determined his death as a suicide, but it has been noted that the known evidence is also consistent with accidental poisoning.In 2009, following an Internet campaign, British Prime Minister Gordon Brown made an official public apology on behalf of the British government for "the appalling way he was treated". Queen Elizabeth II granted Turing a posthumous pardon in 2013. The Alan Turing law is now an informal term for a 2017 law in the United Kingdom that retroactively pardoned men cautioned or convicted under historical legislation that outlawed homosexual acts.NEWS,weblink 'Alan Turing law': Thousands of gay men to be pardoned, 20 October 2016, 20 October 2016, BBC News, On 15 July 2019 the Bank of England announced that Turing would be depicted on the United Kingdom's new £50 note.{{TOC limit|3}}

Early life and education


Turing was born in Maida Vale, London, while his father, Julius Mathison Turing (1873–1947), was on leave from his position with the Indian Civil Service (ICS) at Chatrapur, then in the Madras Presidency and presently in Odisha state, in India.{{Harvnb|Hodges|1983|p=5}}WEB,weblink The Alan Turing Internet Scrapbook, (Alan Turing: The Enigma), 2 January 2012, Turing's father was the son of a clergyman, the Rev. John Robert Turing, from a Scottish family of merchants that had been based in the Netherlands and included a baronet. Turing's mother, Julius' wife, was Ethel Sara Turing (née Stoney 1881–1976), daughter of Edward Waller Stoney, chief engineer of the Madras Railways. The Stoneys were a Protestant Anglo-Irish gentry family from both County Tipperary and County Longford, while Ethel herself had spent much of her childhood in County Clare.Phil Maguire, "An Irishman's Diary", p. 5. The Irish Times, 23 June 2012.Julius' work with the ICS brought the family to British India, where his grandfather had been a general in the Bengal Army. However, both Julius and Ethel wanted their children to be brought up in Britain, so they moved to Maida Vale,WEB,weblinkweblink" title="">weblink 3 September 2009, London Blue Plaques, 10 February 2007, English Heritage, no, dmy, London, where Alan Turing was born on 23 June 1912, as recorded by a blue plaque on the outside of the house of his birth,The Scientific Tourist In London: #17 Alan Turing's Birth Place, Nature. London Blog{{openplaque|381}} later the Colonnade Hotel.WEB,weblink The Alan Turing Internet Scrapbook, 26 September 2006, Turing had an elder brother, John (the father of Sir John Dermot Turing, 12th Baronet of the Turing baronets).Sir John Dermot Turing on the Bletchley Park website.Turing's father's civil service commission was still active and during Turing's childhood years Turing's parents travelled between Hastings in the United Kingdom{{Harvnb|Hodges|1983|p=6}} and India, leaving their two sons to stay with a retired Army couple. At Hastings, Turing stayed at Baston Lodge, Upper Maze Hill, St Leonards-on-Sea, now marked with a blue plaque.NEWS,weblink Plaque unveiled at Turing's home in St Leonards, 29 June 2012, Hastings & St. Leonards Observer, 3 July 2017, The plaque was unveiled on 23 June 2012, the centenary of Turing's birth.NEWS,weblink St Leonards plaque marks Alan Turing's early years, 25 June 2012, BBC News, 3 July 2017, Very early in life, Turing showed signs of the genius that he was later to display prominently.WEB, Alan Turing â€“ Towards a Digital Mind: Part 1, G. James, Jones, 11 December 2001,weblink 27 July 2007, System Toolbox,weblink" title="">weblink 3 August 2007, yes, dmy-all, His parents purchased a house in Guildford in 1927, and Turing lived there during school holidays. The location is also marked with a blue plaque.WEB,weblink Guildford Dragon NEWS, The Guildford Dragon, 29 November 2012, 31 October 2013,


Turing's parents enrolled him at St Michael's, a day school at 20 Charles Road, St Leonards-on-Sea, at the age of six. The headmistress recognised his talent early on, as did many of his subsequent teachers.Between January 1922 and 1926, Turing was educated at Hazelhurst Preparatory School, an independent school in the village of Frant in Sussex (now East Sussex).WEB,weblink Alan Turing Archive – Sherborne School (ARCHON CODE: GB1949), Alan Mathison, Sherborne School, Dorset, April 2016, 5 February 2017, In 1926, at the age of 13, he went on to Sherborne School, a boarding independent school in the market town of Sherborne in Dorset. The first day of term coincided with the 1926 General Strike in Britain, but he was so determined to attend, that he rode his bicycle unaccompanied {{convert|60|mi|km}} from Southampton to Sherborne, stopping overnight at an inn.BOOK, Metamagical Themas: Questing for the Essence of Mind and Pattern, 484, Douglas R., Hofstadter, 1985, Basic Books, 978-0-465-04566-2, 230812136, Turing's natural inclination towards mathematics and science did not earn him respect from some of the teachers at Sherborne, whose definition of education placed more emphasis on the classics. His headmaster wrote to his parents: "I hope he will not fall between two stools. If he is to stay at public school, he must aim at becoming educated. If he is to be solely a Scientific Specialist, he is wasting his time at a public school".{{Harvnb|Hodges|1983|p=26}} Despite this, Turing continued to show remarkable ability in the studies he loved, solving advanced problems in 1927 without having studied even elementary calculus. In 1928, aged 16, Turing encountered Albert Einstein's work; not only did he grasp it, but it is possible that he managed to deduce Einstein's questioning of Newton's laws of motion from a text in which this was never made explicit.{{Harvnb|Hodges|1983|p=34}}

Christopher Morcom

At Sherborne, Turing formed a significant friendship with fellow pupil Christopher Morcom (1911 – 1930), who has been described as Turing's "first love". Their relationship provided inspiration in Turing's future endeavours, but it was cut short by Morcom's death, in February 1930, from complications of bovine tuberculosis, contracted after drinking infected cow's milk some years previously.WEB, Caryl, Christian, Poor Imitation of Alan Turing,weblink New York Review of Books, 19 December 2014, Rachel Hassall, 'The Sherborne Formula: The Making of Alan Turing' 'Vivat!' 2012/13BOOK, Teuscher, Christof, Christof Teuscher, Alan Turing: Life and Legacy of a Great Thinker, 2004, Springer Science+Business Media, Springer-Verlag, 978-3-540-20020-8, 53434737, The event caused Turing great sorrow. He coped with his grief by working that much harder on the topics of science and mathematics that he had shared with Morcom. In a letter to Morcom's mother Turing said:}}Turing's relationship with Morcom's mother continued long after Morcom's death, with her sending gifts to Turing, and him sending letters, typically on Morcom's birthdays.BOOK, Alan Turing: The Enigma, Andrew Hodges, Hodges, Andrew, 87, 2012, 978-0-691-15564-7,weblink A day before the third anniversary of Morcom's death (12 February 1933), he wrote to Mrs. Morcom: }}Some have speculated that Morcom's death was the cause of Turing's atheism and materialism.Paul Gray, Alan Turing Time Magazine's Most Important People of the Century, p. 2 Apparently, at this point in his life he still believed in such concepts as a spirit, independent of the body and surviving death. In a later letter, also written to Morcom's mother, Turing said: }}

University and work on computability

After Sherborne, Turing studied as an undergraduate from 1931 to 1934 at King's College, Cambridge, where he was awarded first-class honours in mathematics. In 1935, at the age of 22, he was elected a fellow of King's on the strength of a dissertation in which he proved the central limit theorem.See Section 3 of John Aldrich, "England and Continental Probability in the Inter-War Years", Journal Electronique d'Histoire des Probabilités et de la Statistique, vol. 5/2 Decembre 2009 Journal Electronique d'Histoire des Probabilités et de la Statistique Unknown to the committee, the theorem had already been proven, in 1922, by Jarl Waldemar Lindeberg.{{Harvnb|Hodges|1983|pp=88, 94}} A blue plaque at the college was unveiled on the centenary of his birth on 23 June 2012 and is now installed at the college's Keynes Building on King's Parade.WEB,weblink Blue plaque to commemorate Alan Turing, King's College, Cambridge, 8 December 2018, WEB,weblink Turing plaque fixed in place, King's College, Cambridge, 8 December 2018, In 1936, Turing published his paper "On Computable Numbers, with an Application to the Entscheidungsproblem".{{Harvnb|Turing|1937}} It was published in the Proceedings of the London Mathematical Society journal in two parts, the first on 30 November and the second on 23 December.BOOK,weblink 211, Computability: Turing, Gödel, Church, and Beyond, B. Jack Copeland, Carl J. Posy, Oron Shagrir, MIT Press, 2013, 9780262018999, In this paper, Turing reformulated Kurt Gödel's 1931 results on the limits of proof and computation, replacing Gödel's universal arithmetic-based formal language with the formal and simple hypothetical devices that became known as Turing machines. The Entscheidungsproblem (decision problem) was originally posed by German mathematician David Hilbert in 1928. Turing proved that his "universal computing machine" would be capable of performing any conceivable mathematical computation if it were representable as an algorithm. He went on to prove that there was no solution to the decision problem by first showing that the halting problem for Turing machines is undecidable: It is not possible to decide algorithmically whether a Turing machine will ever halt.File:20130808 Kings College Front Court Fountain Crop 03.jpg|thumb|right|King's College, CambridgeKing's College, CambridgeAlthough Turing's proof was published shortly after Alonzo Church's equivalent proof using his lambda calculus,{{Harvnb|Church|1936}} Turing's approach is considerably more accessible and intuitive than Church's.WEB, Grime, James, What Did Turing Do for Us?,weblink NRICH, University of Cambridge, 28 February 2016, February 2012, It also included a notion of a 'Universal Machine' (now known as a universal Turing machine), with the idea that such a machine could perform the tasks of any other computation machine (as indeed could Church's lambda calculus). According to the Church–Turing thesis, Turing machines and the lambda calculus are capable of computing anything that is computable. John von Neumann acknowledged that the central concept of the modern computer was due to Turing's paper."von Neumann ... firmly emphasised to me, and to others I am sure, that the fundamental conception is owing to Turing—insofar as not anticipated by Babbage, Lovelace and others." Letter by Stanley Frankel to Brian Randell, 1972, quoted in Jack Copeland (2004) The Essential Turing, p. 22. To this day, Turing machines are a central object of study in theory of computation.From September 1936 to July 1938, Turing spent most of his time studying under Church at Princeton University, in the second year as a Jane Eliza Procter Visiting Fellow. In addition to his purely mathematical work, he studied cryptology and also built three of four stages of an electro-mechanical binary multiplier.{{Harvnb|Hodges|1983|p=138}} In June 1938, he obtained his PhD from the Department of Mathematics at Princeton;TURING > FIRST1 = A.M., Alan Turing, Systems of Logic Based on Ordinals, 10.1112/plms/s2-45.1.161, Proceedings of the London Mathematical Society, 161–228, 1939, s2-45, his dissertation, Systems of Logic Based on Ordinals,{{TuringPhD}}WEB, Turing, A.M., Alan Turing, Systems of Logic Based on Ordinals, 1938,weblink harv, introduced the concept of ordinal logic and the notion of relative computing, where Turing machines are augmented with so-called oracles, allowing the study of problems that cannot be solved by Turing machines. John von Neumann wanted to hire him as his postdoctoral assistant, but he went back to the United Kingdom.John Von Neumann: The Scientific Genius Who Pioneered the Modern Computer, Game Theory, Nuclear Deterrence, and Much More, Norman MacRae, 1999, American Mathematical Society, Chapter 8

Career and research

When Turing returned to Cambridge, he attended lectures given in 1939 by Ludwig Wittgenstein about the foundations of mathematics.{{Harvnb|Hodges|1983|p=152}} The lectures have been reconstructed verbatim, including interjections from Turing and other students, from students' notes.Cora Diamond (ed.), Wittgenstein's Lectures on the Foundations of Mathematics, University of Chicago Press, 1976 Turing and Wittgenstein argued and disagreed, with Turing defending formalism and Wittgenstein propounding his view that mathematics does not discover any absolute truths, but rather invents them.{{Harvnb|Hodges|1983|pp=153–154}}


During the Second World War, Turing was a leading participant in the breaking of German ciphers at Bletchley Park. The historian and wartime codebreaker Asa Briggs has said, "You needed exceptional talent, you needed genius at Bletchley and Turing's was that genius."AV MEDIA, Briggs, Asa, Asa Briggs, Baron Briggs, Britain's Greatest Codebreaker, TV broadcast, Channel 4, UK Channel 4, 21 November 2011, From September 1938, Turing had been working part-time with the Government Code and Cypher School (GC&CS), the British codebreaking organisation. He concentrated on cryptanalysis of the Enigma with Dilly Knox, a senior GC&CS codebreaker.Copeland, Jack, "Colossus and the Dawning of the Computer Age", p. 352 in Action This Day, 2001. Soon after the July 1939 Warsaw meeting at which the Polish Cipher Bureau had provided the British and French with the details of the wiring of Enigma rotors and their method of decrypting Enigma code messages, Turing and Knox started to work on a less fragile approach to the problem.{{Harvnb|Copeland|2004a|p=217}} The Polish method relied on an insecure indicator procedure that the Germans were likely to change, which they did in May 1940. Turing's approach was more general, using crib-based decryption for which he produced the functional specification of the bombe (an improvement of the Polish Bomba).NEWS, Clark, Liat,weblink Turing's achievements: codebreaking, AI and the birth of computer science (Wired UK), Wired, 18 June 2012, 31 October 2013, File:Turing flat.jpg|thumb|right|Two cottages in the stable yard at Bletchley Park. Turing worked here in 1939 and 1940, before moving to Hut 8Hut 8On 4 September 1939, the day after the UK declared war on Germany, Turing reported to Bletchley Park, the wartime station of GC&CS.Copeland, 2006 p. 378.Specifying the bombe was the first of five major cryptanalytical advances that Turing made during the war. The others were: deducing the indicator procedure used by the German navy; developing a statistical procedure for making much more efficient use of the bombes dubbed Banburismus; developing a procedure for working out the cam settings of the wheels of the Lorenz SZ 40/42 (Tunny) dubbed Turingery and, towards the end of the war, the development of a portable secure voice scrambler at Hanslope Park that was codenamed Delilah.By using statistical techniques to optimise the trial of different possibilities in the code breaking process, Turing made an innovative contribution to the subject. He wrote two papers discussing mathematical approaches, titled The Applications of Probability to CryptographyWEB, Turing, Alan, c. 1941, The Applications of Probability to Cryptography, The National Archives (United Kingdom): HW 25/37,weblink harv, and Paper on Statistics of Repetitions,WEB, Turing, Alan, c. 1941, Paper on Statistics of Repetitions, The National Archives (United Kingdom): HW 25/38,weblink harv, which were of such value to GC&CS and its successor GCHQ that they were not released to the UK National Archives until April 2012, shortly before the centenary of his birth. A GCHQ mathematician, "who identified himself only as Richard," said at the time that the fact that the contents had been restricted for some 70 years demonstrated their importance, and their relevance to post-war cryptanalysis:NEWS, Vallance, Chris, Alan Turing papers on code breaking released by GCHQ,weblink 20 April 2012, BBC News, 19 April 2012, Turing had a reputation for eccentricity at Bletchley Park. He was known to his colleagues as "Prof" and his treatise on Enigma was known as the "Prof's Book".{{Harvnb|Hodges|1983|p=208}} According to historian Ronald Lewin, Jack Good, a cryptanalyst who worked with Turing, said of his colleague:}}While working at Bletchley, Turing, who was a talented long-distance runner, occasionally ran the {{convert|40|mi}} to London when he was needed for meetings,BOOK, Brown, Anthony Cave, Anthony Cave Brown, Bodyguard of Lies: The Extraordinary True Story Behind D-Day, The Lyons Press, 1975, 978-1-59921-383-5, harv, and he was capable of world-class marathon standards.NEWS,weblink An Olympic honour for Alan Turing, Graham-Cumming, John, The Guardian, 10 March 2010, London, WEB, Pat, Butcher,weblink In Praise of Great Men, Globe Runner, 14 September 2009, Turing tried out for the 1948 British Olympic team but he was hampered by an injury. His tryout time for the marathon was only 11 minutes slower than British silver medallist Thomas Richards' Olympic race time of 2 hours 35 minutes. He was Walton Athletic Club's best runner, a fact discovered when he passed the group while running alone.WEB, Hodges, Andrew, Andrew Hodges, Alan Turing: a short biography,weblink Alan Turing: The Enigma, 12 June 2014, NEWS, Graham-Cumming, John, John Graham-Cumming, Alan Turing: a short biography,weblink The Guardian, 10 March 2010, 12 June 2014, WEB, Butcher, Pat, Turing as a runner,weblink The MacTutor History of Mathematics archive, December 1999, 12 June 2014, In 1946, Turing was appointed an Officer of the Order of the British Empire (OBE) by King George VI for his wartime services, but his work remained secret for many years.NEWS, Alan Turing: Colleagues share their memories,weblink 23 June 2012, BBC News, WEB,weblink This month in history: Alan Turing and the Enigma code,, 6 February 2019,


Within weeks of arriving at Bletchley Park, Turing had specified an electromechanical machine called the bombe, which could break Enigma more effectively than the Polish bomba kryptologiczna, from which its name was derived. The bombe, with an enhancement suggested by mathematician Gordon Welchman, became one of the primary tools, and the major automated one, used to attack Enigma-enciphered messages.{{Citation |last= Welchman |first= Gordon |author-link= Gordon Welchman |origyear= 1982 |year= 1997 |title= The Hut Six story: Breaking the Enigma codes |page= 81 |location= Cleobury Mortimer, England |publisher= M&M Baldwin |isbn= 978-0-947712-34-1 }}File:Bombe-rebuild.jpg|thumbnail|right|A complete and working replica of a bombe now at The National Museum of ComputingThe National Museum of ComputingThe bombe searched for possible correct settings used for an Enigma message (i.e., rotor order, rotor settings and plugboard settings) using a suitable crib: a fragment of probable plaintext. For each possible setting of the rotors (which had on the order of 1019 states, or 1022 states for the four-rotor U-boat variant),Professor Jack Good in "The Men Who Cracked Enigma", 2003: with his caveat: "if my memory is correct". the bombe performed a chain of logical deductions based on the crib, implemented electromechanically.{{Citation needed|date=July 2018}}The bombe detected when a contradiction had occurred and ruled out that setting, moving on to the next. Most of the possible settings would cause contradictions and be discarded, leaving only a few to be investigated in detail. A contradiction would occur when an enciphered letter would be turned back into the same plaintext letter, which was impossible with the Enigma. The first bombe was installed on 18 March 1940.{{Harvnb|Oakley|2006|p=40/03B}}By late 1941, Turing and his fellow cryptanalysts Gordon Welchman, Hugh Alexander and Stuart Milner-Barry were frustrated. Building on the work of the Poles, they had set up a good working system for decrypting Enigma signals, but their limited staff and bombes meant they could not translate all the signals. In the summer, they had considerable success, and shipping losses had fallen to under 100,000 tons a month; however, they badly needed more resources to keep abreast of German adjustments. They had tried to get more people and fund more bombes through the proper channels, but had failed.On 28 October they wrote directly to Winston Churchill explaining their difficulties, with Turing as the first named. They emphasised how small their need was compared with the vast expenditure of men and money by the forces and compared with the level of assistance they could offer to the forces.{{Harvnb|Hodges|1983|p=218}} As Andrew Hodges, biographer of Turing, later wrote, "This letter had an electric effect."{{Harvnb|Hodges|1983|p=221}} Churchill wrote a memo to General Ismay, which read: "ACTION THIS DAY. Make sure they have all they want on extreme priority and report to me that this has been done." On 18 November, the chief of the secret service reported that every possible measure was being taken. The cryptographers at Bletchley Park did not know of the Prime Minister's response, but as Milner-Barry recalled, "All that we did notice was that almost from that day the rough ways began miraculously to be made smooth."Copeland, The Essential Turing, pp. 336–337. More than two hundred bombes were in operation by the end of the war.WEB, Copeland, Jack, Proudfoot, Diane, Jack Copeland, Alan Turing, Codebreaker and Computer Pioneer,weblink, May 2004, 27 July 2007, File:Turing-statue-Bletchley 14.jpg|thumb|right|upright|Statue of Turing by Stephen Kettle at Bletchley Park, commissioned by Sidney FrankSidney Frank

Hut 8 and the naval Enigma

Turing decided to tackle the particularly difficult problem of German naval Enigma "because no one else was doing anything about it and I could have it to myself".{{Harvnb|Mahon|1945|p=14}} In December 1939, Turing solved the essential part of the naval indicator system, which was more complex than the indicator systems used by the other services.{{Harvnb|Leavitt|2007|pp=184–186}}That same night, he also conceived of the idea of Banburismus, a sequential statistical technique (what Abraham Wald later called sequential analysis) to assist in breaking the naval Enigma, "though I was not sure that it would work in practice, and was not, in fact, sure until some days had actually broken." For this, he invented a measure of weight of evidence that he called the ban. Banburismus could rule out certain sequences of the Enigma rotors, substantially reducing the time needed to test settings on the bombes.JOURNAL, Gladwin, Lee, Fall 1997, Alan Turing, Enigma, and the Breaking of German Machine Ciphers in World War II,weblink Prologue Magazine, Fall 1997, 202–217, National Archives, Later this sequential process of accumulating sufficient weight of evidence using decibans (one tenth of a ban) was used in Cryptanalysis of the Lorenz cipher{{Citation | last = Good | first = Jack | author-link = I. J. Good | last2 = Michie | first2 = Donald | author2-link = Donald Michie | last3 = Timms | first3 = Geoffrey | title = General Report on Tunny: With Emphasis on Statistical Methods | year = 1945 | id = UK Public Record Office HW 25/4 and HW 25/5 | url =weblink |at= Part 3 Organisation: 38 Wheel-breaking from Key, Page 293 }}Turing travelled to the United States in November 1942{{Harvnb|Hodges|1983|pp=242–245}} and worked with US Navy cryptanalysts on the naval Enigma and bombe construction in Washington; he also visited their Computing Machine Laboratory in Dayton, Ohio.Turing's reaction to the American bombe design was far from enthusiastic:|source=}}During this trip, he also assisted at Bell Labs with the development of secure speech devices.{{Harvnb|Hodges|1983|pp=245–253}} He returned to Bletchley Park in March 1943. During his absence, Hugh Alexander had officially assumed the position of head of Hut 8, although Alexander had been de facto head for some time (Turing having little interest in the day-to-day running of the section). Turing became a general consultant for cryptanalysis at Bletchley Park.WEB,weblink Marshall Legacy Series: Codebreaking - Events,, 2019-04-07, Alexander wrote of Turing's contribution:}}


In July 1942, Turing devised a technique termed Turingery (or jokingly Turingismus){{Harvnb|Copeland|2006|p=380}} for use against the Lorenz cipher messages produced by the Germans' new Geheimschreiber (secret writer) machine. This was a teleprinter rotor cipher attachment codenamed Tunny at Bletchley Park. Turingery was a method of wheel-breaking, i.e., a procedure for working out the cam settings of Tunny's wheels.{{Harvnb|Copeland|2006|p=381}} He also introduced the Tunny team to Tommy Flowers who, under the guidance of Max Newman, went on to build the Colossus computer, the world's first programmable digital electronic computer, which replaced a simpler prior machine (the Heath Robinson), and whose superior speed allowed the statistical decryption techniques to be applied usefully to the messages.{{Harvnb|Copeland|2006|p=72}} Some have mistakenly said that Turing was a key figure in the design of the Colossus computer. Turingery and the statistical approach of Banburismus undoubtedly fed into the thinking about cryptanalysis of the Lorenz cipher,{{Harvnb|Gannon|2007|p=230}}{{Harvnb|Hilton|2006|pp=197–199}} but he was not directly involved in the Colossus development.{{Harvnb|Copeland|2006|pp=382, 383}}


Following his work at Bell Labs in the US,{{Harvnb|Hodges|1983|pp=245–250}} Turing pursued the idea of electronic enciphering of speech in the telephone system. In the latter part of the war, he moved in order to work for the Secret Service's Radio Security Service (later HMGCC) at Hanslope Park. At the park, he further developed his knowledge of electronics with the assistance of engineer Donald Bayley. Together they undertook the design and construction of a portable secure voice communications machine codenamed Delilah.{{Harvnb|Hodges|1983|p=273}} The machine was intended for different applications, but it lacked the capability for use with long-distance radio transmissions. In any case, Delilah was completed too late to be used during the war. Though the system worked fully, with Turing demonstrating it to officials by encrypting and decrypting a recording of a Winston Churchill speech, Delilah was not adopted for use.{{Harvnb|Hodges|1983|p=346}} Turing also consulted with Bell Labs on the development of SIGSALY, a secure voice system that was used in the later years of the war.

Early computers and the Turing test

File:Alan Turing 78 High Street Hampton blue plaque.jpg|thumb|Plaque, 78 High Street, Hampton ]]Between 1945 and 1947, Turing lived in Hampton, London,{{openplaque|1619}} while he worked on the design of the ACE (Automatic Computing Engine) at the National Physical Laboratory (NPL). He presented a paper on 19 February 1946, which was the first detailed design of a stored-program computer.{{Harvnb|Copeland|2006|p=108}} Von Neumann's incomplete First Draft of a Report on the EDVAC had predated Turing's paper, but it was much less detailed and, according to John R. Womersley, Superintendent of the NPL Mathematics Division, it "contains a number of ideas which are Dr. Turing's own".WEB, Randell, Brian, Brian Randell, A History of Computing in the Twentieth Century: Colossus, 1980,weblink 27 January 2012, harv, citing JOURNAL, Womersley, J.R., John R. Womersley, 'ACE' Machine Project, Executive Committee, National Physical Laboratory, Teddington, Middlesex, 13 February 1946, harv, Although ACE was a feasible design, the secrecy surrounding the wartime work at Bletchley Park led to delays in starting the project and he became disillusioned. In late 1947 he returned to Cambridge for a sabbatical year during which he produced a seminal work on Intelligent Machinery that was not published in his lifetime.See {{harvnb|Copeland|2004b|pp=410–432}} While he was at Cambridge, the Pilot ACE was being built in his absence. It executed its first program on 10 May 1950, and a number of later computers around the world owe much to it, including the English Electric DEUCE and the American Bendix G-15. The full version of Turing's ACE was not built until after his death.WEB,weblink Turing at NPL, According to the memoirs of the German computer pioneer Heinz Billing from the Max Planck Institute for Physics, published by Genscher, Düsseldorf, there was a meeting between Turing and Konrad Zuse.WEB,weblink Did Alan Turing interrogate Konrad Zuse in Göttingen in 1947?, Bruderer, Herbert, 7 February 2013, It took place in Göttingen in 1947. The interrogation had the form of a colloquium. Participants were Womersley, Turing, Porter from England and a few German researchers like Zuse, Walther, and Billing (for more details see Herbert Bruderer, Konrad Zuse und die Schweiz).In 1948, Turing was appointed reader in the Mathematics Department at the Victoria University of Manchester. A year later, he became Deputy Director of the Computing Machine Laboratory, where he worked on software for one of the earliest stored-program computers—the Manchester Mark 1. Turing wrote the first version of the Programmer's Manual for this machine, and was recruited by Ferranti as a consultant in the development of their commercialised machine, the Ferranti Mark 1. He continued to be paid consultancy fees by Ferranti until his death.BOOK,weblink Alan Turing's Manchester, Swinton, Jonathan, Infang Publishing, 2019, 978-0-9931789-2-4, Manchester, During this time, he continued to do more abstract work in mathematics,JOURNAL, Turing, A.M., 10.1093/qjmam/1.1.287, Rounding-Off Errors in Matrix Processes, The Quarterly Journal of Mechanics and Applied Mathematics, 1, 287–308, 1948, 10338.dmlcz/103139, and in "Computing Machinery and Intelligence" (Mind, October 1950), Turing addressed the problem of artificial intelligence, and proposed an experiment that became known as the Turing test, an attempt to define a standard for a machine to be called "intelligent". The idea was that a computer could be said to "think" if a human interrogator could not tell it apart, through conversation, from a human being.Harnad, Stevan (2008) The Annotation Game: On 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 In the paper, Turing suggested that rather than building a program to simulate the adult mind, it would be better rather to produce a simpler one to simulate a child's mind and then to subject it to a course of education. A reversed form of the Turing test is widely used on the Internet; the CAPTCHA test is intended to determine whether the user is a human or a computer.In 1948 Turing, working with his former undergraduate colleague, D.G. Champernowne, began writing a chess program for a computer that did not yet exist. By 1950, the program was completed and dubbed the Turochamp.WEB, Clark, Liat, Turing's achievements: codebreaking, AI and the birth of computer science,weblink Wired, 11 November 2013, In 1952, he tried to implement it on a Ferranti Mark 1, but lacking enough power, the computer was unable to execute the program. Instead, Turing "ran" the program by flipping through the pages of the algorithm and carrying out its instructions on a chessboard, taking about half an hour per move. The game was recorded.Alan Turing vs Alick Glennie (1952) "Turing Test" According to Garry Kasparov, Turing's program "played a recognizable game of chess."Kasparov, Garry, Smart machines will free us all, The Wall Street Journal, 15–16 April 2017, p. c3 The program lost to Turing's colleague Alick Glennie, although it is said that it won a game against Champernowne's wife,Isabel.WEB, O'Connor, J.J., Robertson, E.F., David Gawen Champernowne,weblink MacTutor History of Mathematics archive, School of Mathematics and Statistics, University of St Andrews, Scotland, 22 May 2018, His Turing test was a significant, characteristically provocative, and lasting contribution to the debate regarding artificial intelligence, which continues after more than half a century.JOURNAL, Pinar Saygin, A., Cicekli, I., Akman, V., Minds and Machines, 10, 4, 463–518, 2000, Turing Test: 50 Years Later, 10.1023/A:1011288000451, 11693/24987,

Pattern formation and mathematical biology

(File:Alan-Turing.jpg|thumb|upright|Turing in 1951)When Turing was 39 years old in 1951, he turned to mathematical biology, finally publishing his masterpiece "The Chemical Basis of Morphogenesis" in January 1952. He was interested in morphogenesis, the development of patterns and shapes in biological organisms. He suggested that a system of chemicals reacting with each other and diffusing across space, termed a reaction-diffusion system, could account for "the main phenomena of morphogenesis".NEWS, Alan M., Turing, Alan Turing, The Chemical Basis of Morphogenesis, Philosophical Transactions of the Royal Society of London B, 14 August 1952, 10.1098/rstb.1952.0012, 237, 641, 37–72, 1952RSPTB.237...37T, He used systems of partial differential equations to model catalytic chemical reactions. For example, if a catalyst A is required for a certain chemical reaction to take place, and if the reaction produced more of the catalyst A, then we say that the reaction is autocatalytic, and there is positive feedback that can be modelled by nonlinear differential equations. Turing discovered that patterns could be created if the chemical reaction not only produced catalyst A, but also produced an inhibitor B that slowed down the production of A. If A and B then diffused through the container at different rates, then you could have some regions where A dominated and some where B did. To calculate the extent of this, Turing would have needed a powerful computer, but these were not so freely available in 1951, so he had to use linear approximations to solve the equations by hand. These calculations gave the right qualitative results, and produced, for example, a uniform mixture that oddly enough had regularly spaced fixed red spots. The Russian biochemist Boris Belousov had performed experiments with similar results, but could not get his papers published because of the contemporary prejudice that any such thing violated the second law of thermodynamics. Belousov was not aware of Turing's paper in the Philosophical Transactions of the Royal Society.John Gribbin, Deep Simplicity, p. 126, Random House, 2004Although published before the structure and role of DNA was understood, Turing's work on morphogenesis remains relevant today and is considered a seminal piece of work in mathematical biology.WEB,weblink Turing's Last, Lost work, 28 November 2011, yes,weblink" title="">weblink 23 August 2003, dmy, One of the early applications of Turing's paper was the work by James Murray explaining spots and stripes on the fur of cats, large and small.James Murray, How the leopard gets its spots, Scientific American, vol 258, number 3, p. 80, March 1988James Murray, Mathematical Biology I, 2007, Chapter 6, Springer VerlagJohn Gibbin, Deep Simplicity, p. 134, Random House, 2004 Further research in the area suggests that Turing's work can partially explain the growth of "feathers, hair follicles, the branching pattern of lungs, and even the left-right asymmetry that puts the heart on the left side of the chest."JOURNAL, 10.1126/science.338.6113.1406, 23239707, Turing Pattern Fingered for Digit Formation, Science, 338, 6113, 1406, 2012, Vogel, G., In 2012, Sheth, et al. found that in mice, removal of Hox genes causes an increase in the number of digits without an increase in the overall size of the limb, suggesting that Hox genes control digit formation by tuning the wavelength of a Turing-type mechanism.JOURNAL, Sheth, R., Marcon, L., Bastida, M.F., Junco, M., Quintana, L., Dahn, R., Kmita, M., Sharpe, J., Ros, M.A., 10.1126/science.1226804, Hox Genes Regulate Digit Patterning by Controlling the Wavelength of a Turing-Type Mechanism, Science, 338, 6113, 1476–1480, 2012, 23239739, 4486416, 2012Sci...338.1476S, Later papers were not available until Collected Works of A. M. Turing was published in 1992.WEB, The Alan Turing Bibliography,weblink morphogenesis,, 27 July 2015, Andrew Hodges,

Personal life


In 1941, Turing proposed marriage to Hut 8 colleague Joan Clarke, a fellow mathematician and cryptanalyst, but their engagement was short-lived. After admitting his homosexuality to his fiancée, who was reportedly "unfazed" by the revelation, Turing decided that he could not go through with the marriage.{{Harvnb|Leavitt|2007|pp=176–178}}

Conviction for indecency

In January 1952, Turing was 39 when he started a relationship with Arnold Murray, a 19-year-old unemployed man. Just before Christmas, Turing was walking along Manchester's Oxford Road when he met Murray just outside the Regal Cinema and invited him to lunch. On 23 January, Turing's house was burgled. Murray told Turing that he and the burglar were acquainted, and Turing reported the crime to the police. During the investigation, he acknowledged a sexual relationship with Murray. Homosexual acts were criminal offences in the United Kingdom at that time,{{Harvnb|Hodges|1983|p=458}} and both men were charged with "gross indecency" under Section 11 of the Criminal Law Amendment Act 1885.{{Harvnb|Leavitt|2007|p=268}} Initial committal proceedings for the trial were held on 27 February during which Turing's solicitor "reserved his defence", i.e., did not argue or provide evidence against the allegations.Turing was later convinced by the advice of his brother and his own solicitor, and he entered a plea of guilty.BOOK, Alan Turing: The Enigma, Andrew Hodges, Hodges, Andrew, 463, 2012, 978-0-691-15564-7,weblink The case, Regina v. Turing and Murray, was brought to trial on 31 March 1952.BOOK, Alan Turing: The Enigma, Andrew Hodges, Hodges, Andrew, 471, 2012, 978-0-691-15564-7,weblink Turing was convicted and given a choice between imprisonment and probation. His probation would be conditional on his agreement to undergo hormonal physical changes designed to reduce libido. He accepted the option of injections of what was then called stilboestrol (now known as diethylstilbestrol or DES), a synthetic oestrogen; this feminization of his body was continued for the course of one year. The treatment rendered Turing impotent and caused breast tissue to form,BOOK, Alan Turing: The Enigma The Centenary Edition, Princeton University, Hodges, Andrew, 2012, fulfilling in the literal sense Turing's prediction that "no doubt I shall emerge from it all a different man, but quite who I've not found out".WEB, Letters of Note: Yours in distress, Alan, Turing, Alan, 1952,weblink 20 January 2013,weblink" title="">weblink no, dmy, BOOK, Alan Turing: The Enigma, Andrew Hodges, Hodges, Andrew, xxviii, 2012, 978-0-691-15564-7,weblink Murray was given a conditional discharge.{{Harvnb|Hodges|1983|p=473}}Turing's conviction led to the removal of his security clearance and barred him from continuing with his cryptographic consultancy for the Government Communications Headquarters (GCHQ), the British signals intelligence agency that had evolved from GC&CS in 1946, though he kept his academic job. He was denied entry into the United States after his conviction in 1952, but was free to visit other European countries. Turing was never accused of espionage but, in common with all who had worked at Bletchley Park, he was prevented by the Official Secrets Act from discussing his war work.{{Harvnb|Copeland|2006|p=143}}


On 8 June 1954, Turing's housekeeper found him dead at the age of 41; he had died the previous day. Cyanide poisoning was established as the cause of death.NEWS,weblink Alan Turing {{!, Biography, Facts, & Education|work=Encyclopædia Britannica|access-date=11 October 2017}} When his body was discovered, an apple lay half-eaten beside his bed, and although the apple was not tested for cyanide,{{Harvnb|Hodges|1983|p=488}} it was speculated that this was the means by which Turing had consumed a fatal dose. An inquest determined that he had committed suicide. Andrew Hodges and another biographer, David Leavitt, have both speculated that Turing was re-enacting a scene from the Walt Disney film Snow White and the Seven Dwarfs (1937), his favourite fairy tale. Both men noted that (in Leavitt's words) he took "an especially keen pleasure in the scene where the Wicked Queen immerses her apple in the poisonous brew."{{Harvnb|Leavitt|2007|p=140}} and {{Harvnb|Hodges|1983|pp=149, 489}} Turing's remains were cremated at Woking Crematorium on 12 June 1954{{Harvnb|Hodges|1983|p=529}} and his ashes were scattered in the gardens of the crematorium, just as his father's had been.BOOK,weblink Alan Turing: The Enigma, Hodges, Andrew, 2012, Random House, 978-1-4481-3781-7, Philosophy professor Jack Copeland has questioned various aspects of the coroner's historical verdict. He suggested an alternative explanation for the cause of Turing's death: the accidental inhalation of cyanide fumes from an apparatus used to electroplate gold onto spoons. The potassium cyanide was used to dissolve the gold. Turing had such an apparatus set up in his tiny spare room. Copeland noted that the autopsy findings were more consistent with inhalation than with ingestion of the poison. Turing also habitually ate an apple before going to bed, and it was not unusual for the apple to be discarded half-eaten.NEWS, Roland, Pease, Alan Turing: Inquest's suicide verdict 'not supportable',weblink BBC News, 23 June 2012, 23 June 2012, We have ... been recreating the narrative of Turing's life, and we have recreated him as an unhappy young man who committed suicide. But the evidence is not there", In addition, Turing had reportedly borne his legal setbacks and hormone treatment (which had been discontinued a year previously) "with good humour" and had shown no sign of despondency prior to his death. He even set down a list of tasks that he intended to complete upon returning to his office after the holiday weekend. Turing's mother believed that the ingestion was accidental, resulting from her son's careless storage of laboratory chemicals.WEB,weblink TURING, Ethel Sara (1881-1976, mother of Alan Turing). Series of 11 autograph letters to Robin Gandy, Guilford, 28 July 1954 - 11 June 1971 (most before 1959), altogether 29 pages, 8vo (2 letters dated 17 May and 26 May 1955 incomplete, lacking continuation leaves, occasional light soiling).,, 6 February 2019, Biographer Andrew Hodges theorised that Turing arranged the delivery of the equipment in order to deliberately allow his mother plausible deniability with regard to any suicide claims.{{Harvnb|Hodges|1983|pp=488, 489}}File:Alan Turing OBE.jpg|thumb|Turing's OBE currently held in Sherborne SchoolSherborne SchoolConspiracy theorists pointed out that Turing was the cause of intense anxiety to the British authorities at the time of his death. The secret services feared that communists would entrap prominent homosexuals and use them to gather intelligence. Turing was still engaged in highly classified work when he was also a practising homosexual who holidayed in European countries near the Iron Curtain. According to the conspiracy theory, it is possible that the secret services considered him too great a security risk and assassinated one of the most brilliant minds in their employ.BOOK, Joel, Levy, Mathematics: A curious history - From Early Number Concepts To The Chaos Theory, Carlton Publishing Group, Andre Deutsch, London, 2018, 9780233005447, 177, It has been suggested that Turing's belief in fortune-telling may have caused his depressed mood. As a youth, Turing had been told by a gypsy fortune-teller that he would be a genius. Shortly before his death, during a day-trip to St Annes-on-Sea with the Greenbaum family,{{when|date=January 2019}} Turing again decided to consult a fortune-teller. According to the Greenbaums' daughter, Barbara:But it was a lovely sunny day and Alan was in a cheerful mood and off we went... Then he thought it would be a good idea to go to the Pleasure Beach at Blackpool. We found a fortune-teller's tent and Alan said he'd like to go in so we waited around for him to come back... And this sunny, cheerful visage had shrunk into a pale, shaking, horror-stricken face. Something had happened. We don't know what the fortune-teller said but he obviously was deeply unhappy. I think that was probably the last time we saw him before we heard of his suicide."WEB,weblink What was Alan Turing really like?, Vincent Dowd,, 6 June 2014,

Government apology and pardon

{{anchor|Government apology and pardon support}}In August 2009, British programmer John Graham-Cumming started a petition urging the British government to apologise for Turing's prosecution as a homosexual.BOOK, Thousands call for Turing apology,weblink BBC News, 31 August 2009, 31 August 2009, BOOK, Petition seeks apology for Enigma code-breaker Turing,weblink CNN, 1 September 2009, 1 September 2009,weblink" title="">weblink 5 October 2009, no, The petition received more than 30,000 signatures.The petition was only open to UK citizens. The Prime Minister, Gordon Brown, acknowledged the petition, releasing a statement on 10 September 2009 apologising and describing the treatment of Turing as "appalling":NEWS, PM's apology to codebreaker Alan Turing: we were inhumane,weblink The Guardian, UK, 11 September 2009, Caroline, Davies, NEWS,weblink PM apology after Turing petition, 11 September 2009, BBC News, In December 2011, William Jones and his Member of Parliament, John Leech, created an e-petitionWEB, Grant a pardon to Alan Turing,weblink 6 December 2011, yes,weblink" title="">weblink 10 January 2012, dmy-all, requesting that the British government pardon Turing for his conviction of "gross indecency":NEWS, Petition to pardon computer pioneer Alan Turing started,weblink 6 December 2011, BBC News, The petition gathered over 37,000 signatures,NEWS,weblink Alan Turing gets his royal pardon for 'gross indecency' â€“ 61 years after he poisoned himself, The Independent, 23 December 2013, Wright, Oliver, London, and was submitted to Parliament by the Manchester MP John Leech but the request was discouraged by Justice Minister Lord McNally, who said:WEB, Government rejects a pardon for computer genius Alan Turing,weblink 7 February 2012, Wainwright, Martin, The Guardian, }}John Leech, the MP for Manchester Withington (2005–15), submitted several bills to ParliamentWEB,weblink Better late than never, Alan Turing is finally pardoned, Alex, Stevenson,, 25 September 2016, and led a high-profile campaign to secure the pardon. Leech made the case in the House of Commons that Turing's contribution to the war made him a national hero and that it was "ultimately just embarrassing" that the conviction still stood.WEB,weblink Alan Turing's court convictions go on display for the first time, Todd, Fitzgerald, 24 September 2016,, 25 September 2016, Leech continued to take the bill through Parliament and campaigned for several years until it was passed.NEWS,weblink MP calls for pardon for computer pioneer Alan Turing, 1 February 2012, BBC News, 25 September 2016, Leech is now regularly described as the "architect" of Turing's pardon and subsequently the Alan Turing Law which went on to secure pardons for 75,000 other men and women convicted of similar crimesweblink At the UK premiere of a film based on Turing's life, The Imitation Game, the producers thanked Leech for bringing the topic to public attention and securing Turing's pardon.NEWS,weblink My proudest day as a Liberal Democrat, Liberal Democrat Voice, 2018-06-24, en-US, His campaign turned to acquiring pardons for the 75,000 other men convicted of the same crime. Leech's campaign gained public support from leading scientists, including Stephen Hawking.NEWS,weblink Alan Turing pardoned by The Queen for his 'unjust and discriminatory' conviction for homosexuality, Britton, Paul, Manchester Evening News, 2013-12-24, 2018-06-24, On 26 July 2012, a bill was introduced in the House of Lords to grant a statutory pardon to Turing for offences under section 11 of the Criminal Law Amendment Act 1885, of which he was convicted on 31 March 1952.WEB,weblink Bill, Parliament of the United Kingdom, 26 July 2012, 31 October 2013, Late in the year in a letter to The Daily Telegraph, the physicist Stephen Hawking and 10 other signatories including the Astronomer Royal Lord Rees, President of the Royal Society Sir Paul Nurse, Lady Trumpington (who worked for Turing during the war) and Lord Sharkey (the bill's sponsor) called on Prime Minister David Cameron to act on the pardon request.Pearse, Damian, "Alan Turing should be pardoned, argue Stephen Hawking and top scientists", The Guardian, 13 December 2012. Retrieved 15 December 2012. The government indicated it would support the bill,NEWS,weblink Enigma codebreaker Alan Turing to be given posthumous pardon, The Guardian, 19 July 2013, Watt, Nicholas, London, NEWS,weblink Alan Turing pardon sails through House of Lords, Worth, Dan, 30 October 2013, V3, 24 December 2013, WEB, Alan Turing (Statutory Pardon) Bill,weblink 20 July 2013, harv, and it passed its third reading in the Lords in October.NEWS,weblink Lib Dem MP John Leech disappointed at delay to Alan Turing pardon bill, Pink News, 2 December 2013, Roberts, Scott, At the bill's second reading in the House of Commons on 29 November 2013, Conservative MP Christopher Chope objected to the bill, delaying its passage. The bill was due to return to the House of Commons on 28 February 2014,NEWS,weblink Lib Dem MP John Leech disappointed at delay to Alan Turing pardon bill, Roberts, Scott, 2 December 2013, PinkNews, 20 June 2018, en-US, but before the bill could be debated in the House of Commons,WEB, Alan Turing (Statutory Pardon) Bill,weblink 24 December 2013, harv, the government elected to proceed under the royal prerogative of mercy. On 24 December 2013, Queen Elizabeth II signed a pardon for Turing's conviction for "gross indecency", with immediate effect.WEB,weblink Alan Turing granted Royal pardon by the Queen, Swinford, Steven, 23 December 2013, The Daily Telegraph, Announcing the pardon, Lord Chancellor Chris Grayling said Turing deserved to be "remembered and recognised for his fantastic contribution to the war effort" and not for his later criminal conviction.NEWS, Royal pardon for codebreaker Alan Turing,weblink 24 December 2013, BBC News, 24 December 2013, The Queen officially pronounced Turing pardoned in August 2014.WEB,weblink With Queen's Decree, Alan Turing Is Now Officially Pardoned,, 1 November 2014, The Queen's action is only the fourth royal pardon granted since the conclusion of the Second World War.Pardoned: Alan Turing, Computing patriarch. Time Magazine, vol. 183, no. 1, 13 January 2014, p. 14. Retrieved 6 January 2014. Pardons are normally granted only when the person is technically innocent, and a request has been made by the family or other interested party; neither condition was met in regard to Turing's conviction.NEWS, Davies, Caroline, Codebreaker Turing is given posthumous royal pardon, The Guardian, London, 1, 6, 24 December 2013, In a letter to the Prime Minister, David Cameron, human rights advocate Peter Tatchell criticised the decision to single out Turing due to his fame and achievements when thousands of others convicted under the same law have not received pardons.NEWS, Peter, Tatchell, Alan Turing: Was He Murdered By the Security Services?,weblink The Huffington Post UK, 24 December 2013, 29 December 2013, Tatchell also called for a new investigation into Turing's death:}}In September 2016, the government announced its intention to expand this retroactive exoneration to other men convicted of similar historical indecency offences, in what was described as an "Alan Turing law".NEWS,weblink Government 'committed' to Alan Turing gay pardon law, 22 September 2016, BBC News, 22 September 2016, WEB,weblink Theresa May committed to introducing the 'Alan Turing Law', Cowburn, Ashley, 21 September 2016, The Independent, 22 September 2016, The Alan Turing law is now an informal term for the law in the United Kingdom, contained in the Policing and Crime Act 2017, which serves as an amnesty law to retroactively pardon men who were cautioned or convicted under historical legislation that outlawed homosexual acts. The law applies in England and Wales.WEB,weblink Policing and Crime Act 2017, Expert, Participation,, 6 February 2019,

Awards, honours, and tributes

File:Alan Turing Building 1.jpg|thumb|The Alan Turing BuildingAlan Turing BuildingTuring was appointed an officer of the Order of the British Empire 1946. He was also elected a Fellow of the Royal Society (FRS) in 1951. Several things are named in his honour:{{Div col|colwidth=35em}} {{colend}}

Posthumous tributes

Various institutions have paid tribute to Turing by naming things after him including:{{Div col|colwidth=35em}} {{colend}}A biography published by the Royal Society shortly after Turing's death, while his wartime work was still subject to the Official Secrets Act, recorded:Since 1966, the Turing Award has been given annually by the Association for Computing Machinery for technical or theoretical contributions to the computing community. It is widely considered to be the computing world's highest honour, equivalent to the Nobel Prize.WEB,weblink ACM'S Turing Award Prize Raised To $250,000, Association for Computing Machinery, ACM press release, 27 July 2007, 16 October 2008, Geringer, Steven, yes,weblink" title="">weblink 30 December 2008, dmy-all, On 23 June 1998, on what would have been Turing's 86th birthday, his biographer, Andrew Hodges, unveiled an official English Heritage blue plaque at his birthplace in Warrington Crescent, London, later the Colonnade Hotel.WEB,weblink Unveiling the official Blue Plaque on Alan Turing's Birthplace, 26 September 2006, WEB,weblinkweblink" title="">weblink 13 October 2007, About this Plaque â€“ Alan Turing, 25 September 2006, To mark the 50th anniversary of his death, a memorial plaque was unveiled on 7 June 2004 at his former residence, Hollymeade, in Wilmslow, Cheshire.{{openplaque|3276}}File:Turing Plaque.jpg|thumb|right|A blue plaque marking Turing's home at WilmslowWilmslowOn 13 March 2000, Saint Vincent and the Grenadines issued a set of postage stamps to celebrate the greatest achievements of the 20th century, one of which carries a portrait of Turing against a background of repeated 0s and 1s, and is captioned: "1937: Alan Turing's theory of digital computing". On 1 April 2003, Turing's work at Bletchley Park was named an IEEE Milestone.WEB,weblink Milestones:Code-breaking at Bletchley Park during World War II, 1939–1945, IEEE History Center, 2003, IEEE Global History Network, IEEE, 29 March 2012, On 28 October 2004, a bronze statue of Turing sculpted by John W. Mills was unveiled at the University of Surrey in Guildford, marking the 50th anniversary of Turing's death; it portrays him carrying his books across the campus.PRESS RELEASE,weblink The Earl of Wessex unveils statue of Alan Turing, October 2004, University of Surrey,weblink" title="">weblink 23 October 2007, yes, Turing was one of four mathematicians examined in the BBC documentary entitled Dangerous Knowledge (2008).WEB,weblink Dangerous Knowledge, BBC Four, 11 June 2008,weblink" title="">weblink 2 November 2011, The Princeton Alumni Weekly named Turing the second most significant alumnus in the history of Princeton University, second only to President James Madison. A 1.5-ton, life-size statue of Turing was unveiled on 19 June 2007 at Bletchley Park. Built from approximately half a million pieces of Welsh slate, it was sculpted by Stephen Kettle, having been commissioned by the American billionaire Sidney Frank.Bletchley Park Unveils Statue Commemorating Alan Turing, Bletchley Park press release, 20 June 2007.Turing has been honoured in various ways in Manchester, the city where he worked towards the end of his life. In 1994, a stretch of the A6010 road (the Manchester city intermediate ring road) was named "Alan Turing Way". A bridge carrying this road was widened, and carries the name Alan Turing Bridge. A statue of Turing was unveiled in Manchester on 23 June 2001 in Sackville Park, between the University of Manchester building on Whitworth Street and Canal Street. The memorial statue depicts the "father of computer science" sitting on a bench at a central position in the park. Turing is shown holding an apple. The cast bronze bench carries in relief the text 'Alan Mathison Turing 1912–1954', and the motto 'Founder of Computer Science' as it could appear if encoded by an Enigma machine: 'IEKYF ROMSI ADXUO KVKZC GUBJ'. However, the meaning of the coded message is disputed, as the 'u' in 'computer' matches up with the 'u' in 'ADXUO'. As a letter encoded by an enigma machine can not appear as itself, the actual message behind the code is uncertain.NEWS,weblink What does the code on the Alan Turing Memorial actually say?, 2010-09-23, Random Hacks, 2018-06-28, en-US, File:Sackville Park Turing plaque.jpg|thumb|right|Turing memorial statue plaque in Sackville ParkSackville ParkA plaque at the statue's feet reads 'Father of computer science, mathematician, logician, wartime codebreaker, victim of prejudice'. There is also a Bertrand Russell quotation: "Mathematics, rightly viewed, possesses not only truth, but supreme beauty—a beauty cold and austere, like that of sculpture." The sculptor buried his own old Amstrad computer under the plinth as a tribute to "the godfather of all modern computers".NEWS,weblink Computer buried in tribute to genius, Manchester Evening News, 17 February 2007, 7 December 2014, In 1999, Time magazine named Turing as one of the (Time 100: The Most Important People of the Century|100 Most Important People of the 20th century) and stated, "The fact remains that everyone who taps at a keyboard, opening a spreadsheet or a word-processing program, is working on an incarnation of a Turing machine."NEWS, Alan Turing â€“ Time 100 People of the Century,weblink Time, Providing a blueprint for the electronic digital computer. The fact remains that everyone who taps at a keyboard, opening a spreadsheet or a word-processing program, is working on an incarnation of a Turing machine., Paul, Gray, 29 March 1999, In 2002, Turing was ranked twenty-first on the BBC's poll of the 100 Greatest Britons following a UK-wide vote.NEWS,weblink 100 great British heroes, 21 August 2002, BBC News, In 2006, British writer and mathematician Ioan James chose Turing as one of twenty people to feature in his book about famous historical figures who may have had some of the traits of Asperger syndrome.BOOK, James, Ioan M., Asperger's Syndrome and High Achievement,weblink Jessica Kingsley, 2006, 978-1-84310-388-2, In 2010, actor/playwright Jade Esteban Estrada portrayed Turing in the solo musical, Icons: The Lesbian and Gay History of the World, Vol. 4. In 2011, in The Guardian{{'}}s "My hero" series, writer Alan Garner chose Turing as his hero and described how they had met while out jogging in the early 1950s. Garner remembered Turing as "funny and witty" and said that he "talked endlessly".NEWS, Alan Garner,weblink My Hero: Alan Turing, Saturday Guardian Review, 12 November 2011, 23 November 2011, Garner, Alan, 5, harv, London, In 2006, Turing was named with online resources as an LGBT History Month Icon.WEB,weblink Alan Turing,, 20 August 2011, 15 January 2014, In 2006, Boston Pride named Turing their Honorary Grand Marshal.WEB,weblink Boston Pride: Honorary Grand Marshal, 23 November 2017,weblink" title="">weblink 19 June 2006, dmy, yes, File:Alan Turing Memorial Closer.jpg|thumb|upright|right|Turing memorial statue in Sackville ParkSackville ParkThe logo of Apple Inc. is often erroneously referred to as a tribute to Turing, with the bite mark a reference to his death.NEWS,weblink Logos that became legends: Icons from the world of advertising, The Independent, UK, 14 September 2009, 4 January 2008,weblink" title="">weblink 3 October 2009, no, Both the designer of the logoWEB,weblink Interview with Rob Janoff, designer of the Apple logo, creativebits, 14 September 2009, and the company deny that there is any homage to Turing in the design.{{Harvnb|Leavitt|2007|p=280}}WEB,weblink Turing and the Apple logo, 25 December 2015, 25 July 2015, yes,weblink" title="">weblink 25 December 2015, dmy-all, Stephen Fry has recounted asking Steve Jobs whether the design was intentional, saying that Jobs' response was, "God, we wish it were.""Science & Environment â€“ Alan Turing: Separating the man and the myth". BBC. Retrieved 23 June 2012. In February 2011, Turing's papers from the Second World War were bought for the nation with an 11th-hour bid by the National Heritage Memorial Fund, allowing them to stay at Bletchley Park.NEWS, Halliday, Josh,weblink Turing papers to stay in UK after 11th-hour auction bid at, The Guardian, UK, 29 May 2011, 25 February 2011, In 2012, Turing was inducted into the Legacy Walk, an outdoor public display that celebrates LGBT history and people.WEB,weblink 2012 INDUCTEES, Salvo, Victor, The Legacy Project, 1 November 2014, WEB,weblink PHOTOS: 7 LGBT Heroes Honored With Plaques in Chicago's Legacy Walk,, 1 November 2014, The song "Alan et la Pomme", by francophone singer-songwriter Salvatore Adamo, is a tribute to Turing.AV MEDIA, Alan et la Pomme â€“ Salvatore Adamo,weblink YouTube, 26 December 2013, Kamiab, Farbod, 20 November 2012, {{better source|date=December 2017}} Turing's life and work featured in a BBC children's programme about famous scientists, Absolute Genius with Dick and Dom, first broadcast on 12 March 2014.On 17 May 2014, the world's first work of public art to recognise Turing as gay was commissioned in Bletchley, close by to Bletchley Park where his war-time work was carried out. The commission was announced to mark International Day Against Homophobia, Transphobia and Biphobia. The work was unveiled at a ceremony on Turing's birthday, 23 June 2014, and is placed alongside busy Watling Street, the old main road to London, where Turing himself would have passed by on many occasions. On 22 October 2014, Turing was inducted into the NSA Hall of Honor.WEB, Cryptologic Hall of Honor – Alan Turing,weblink National Security Agency, 14 February 2017, 22 October 2014, PRESS RELEASE, Five Cryptologists Added to NSA/CSS Cryptologic Hall of Honor,weblink National Security Agency, 14 February 2017, 22 October 2014, In 2014 Turing was one of the inaugural honorees in the Rainbow Honor Walk, a walk of fame in San Francisco’s Castro neighborhood noting LGBTQ people who have "made significant contributions in their fields."WEB,weblink The Rainbow Honor Walk: San Francisco's LGBT Walk of Fame, Shelter, Scott, March 14, 2016, Quirky Travel Guy, en-US, 2019-07-28, WEB,weblink Castro's Rainbow Honor Walk Dedicated Today: SFist, September 2, 2014, SFist - San Francisco News, Restaurants, Events, & Sports, WEB,weblink Second LGBT Honorees Selected for San Francisco's Rainbow Honor Walk, Carnivele, Gary, July 2, 2016, We The People, 2019-08-12, In February 2019, in the BBC eight-part TV series (Icons: The Greatest Person of the 20th Century), Turing was voted by viewers to be the Greatest Person.WEB,weblink BBC Two - Icons: The Greatest Person of the 20th Century, BBC, 6 February 2019, In July 2019, the Bank of England announced that Turing's portrait would appear on the next edition of the Bank of England £50 note, to be released in 2021.WEB,weblink New face of the £50 note is revealed, Kevin, Peachey, 15 July 2019, 15 July 2019,, WEB, Press, The Associated, Codebreaker Alan Turing to be face of new British banknote,weblink Richmond Times-Dispatch, 16 July 2019, en,

Centenary celebrations

File:David Chalmers, delivering a talk at De La Salle University-Manila, March 27, 2012.jpg|thumb|right|David Chalmers on stage for an Alan Turing Year conference at De La Salle UniversityDe La Salle UniversityTo mark the 100th anniversary of Turing's birth, the Turing Centenary Advisory Committee (TCAC) co-ordinated the Alan Turing Year, a year-long programme of events around the world honouring Turing's life and achievements. The TCAC, chaired by S. Barry Cooper with Turing's nephew Sir John Dermot Turing acting as Honorary President, worked with the University of Manchester faculty members and a broad spectrum of people from Cambridge University and Bletchley Park.On 23 June 2012, Google featured an interactive doodle where visitors had to change the instructions of a Turing Machine, so when run, the symbols on the tape would match a provided sequence, featuring "Google" in Baudot-Murray code.NEWS,weblink Google Doodle honors Alan Turing, USA Today, 22 June 2012, 23 June 2012, The Bletchley Park Trust collaborated with Winning Moves to publish an Alan Turing edition of the board game Monopoly. The game's squares and cards have been revised to tell the story of Turing's life, from his birthplace in Maida Vale to Hut 8 at Bletchley Park.NEWS,weblink Special Monopoly edition celebrates Alan Turing's life, BBC News, 10 September 2012, 10 September 2012, The game also includes a replica of an original hand-drawn board created by William Newman, son of Turing's mentor, Max Newman, which Turing played on in the 1950s.WEB,weblink Bletchley Park Launches Special Edition Alan Turing Monopoly Board, 13 September 2012, In the Philippines, the Department of Philosophy at De La Salle University-Manila hosted Turing 2012, an international conference on philosophy, artificial intelligence, and cognitive science from 27 to 28 March 2012 to commemorate the centenary birth of Turing.NEWS,weblink DLSU to host int'l summit on philosophy,, 24 March 2012, 18 December 2013, NEWS,weblink The Thinking Machine: A philosophical analysis of the Singularity, GMA News Online, 21 April 2012, 18 December 2013, Layug-Rosero, Regina, Madurai, India held celebrations with a programme attended by 6,000 students.NEWS,weblink Making themselves heard, The Hindu, 5 July 2012, 31 October 2013, Shankar, M. Gopi, Chennai, India, File:Alan Turing Olympic Torch.jpg|thumbnail|The London 2012 Olympic Torch flame was passed on in front of Turing's statue in Manchester on his 100th birthday.]]There was a three-day conference in Manchester in June, the Alan Turing Centenary Conference, a two-day conference in San Francisco, organised by the ACM, and a birthday party and Turing Centenary Conference in Cambridge organised at King's College, Cambridge, and the University of Cambridge, the latter organised by the association Computability in Europe.WEB,weblink The Northerner: Alan Turing, computer pioneer, has centenary marked by a year of celebrations, The Guardian,, 23 February 2011, 29 May 2011, The Science Museum in London launched a free exhibition devoted to Turing's life and achievements in June 2012, to run until July 2013.NEWS, 18 June 2012, 23 June 2012, Rory Cellan-Jones, Rory, David, Cellan-Jones,weblink Enigma? First look at Alan Turing exhibition (report with video preview), BBC News, Rooney (curator), In February 2012, the Royal Mail issued a stamp featuring Turing as part of its "Britons of Distinction" series.NEWS,weblink Codebreaker Alan Turing gets stamp of approval, Gizmodo, 2 January 2012, 2 January 2012, Cutlack, Gary, The London 2012 Olympic Torch flame was passed on in front of Turing's statue in Sackville Gardens, Manchester, on the evening of 23 June 2012, the 100th anniversary of his birth.On 22 June 2012 Manchester City Council, in partnership with the Lesbian and Gay Foundation, launched the Alan Turing Memorial Award, which will recognise individuals or groups who have made a significant contribution to the fight against homophobia in Manchester.NEWS,weblink Centenary award tribute to "enigma" codebreaker Alan Turing., Anon, 22 June 2012, Manchester Evening News, MEN media, 22 June 2012, Manchester, At the University of Oxford, a new course in Computer Science and Philosophy was established to coincide with the centenary of Turing's birth. A new undergraduate degree course, with its first students having started in 2012, the centenary of Alan Turing's birth.Previous events have included a celebration of Turing's life and achievements, at the University of Manchester, arranged by the British Logic Colloquium and the British Society for the History of Mathematics on 5 June 2004.WEB,weblink BSHM Meetings (1992–2007), University of Warwick, 24 December 2013,


In theatre

File:Benedict Cumberbatch 2013 TIFF (headshot).jpg|thumb|upright|Benedict Cumberbatch portrayed Turing in the 2014 film The Imitation GameThe Imitation Game
  • Breaking the Code is a 1986 play by Hugh Whitemore about Turing. The play ran in London's West End beginning in November 1986 and on Broadway from 15 November 1987 to 10 April 1988. In these performances Turing was played by Derek Jacobi. The Broadway production was nominated for three Tony Awards including Best Actor in a Play, Best Featured Actor in a Play, and Best Direction of a Play, and for two Drama Desk Awards, for Best Actor and Best Featured Actor. Turing was again portrayed by Jacobi in the 1996 television film adaptation of Breaking the Code.NEWS, Alan Turing: A multitude of lives in fiction,weblink BBC News, 23 June 2012,
  • In 2012, in honour of the Turing Centennial, American Lyric Theater commissioned an operatic exploration of the life and death of Turing from composer Justine F. Chen and librettist David Simpatico.WEB,weblink The Life and Death(s) of Alan Turing – a new opera, American Lyric Theater, yes,weblink" title="">weblink 22 January 2015, dmy-all, Titled The Life and Death(s) of Alan Turing, the opera is a historical fantasia on the life of Turing. In November 2014, the opera and several other artistic works inspired by Turing's life were featured on Studio 360.WEB,weblink Alan Turing, Man and Myth – Studio 360, studio360, yes,weblink" title="">weblink 22 January 2015, dmy-all, The opera received its first public performance in January 2017.WEB,weblink Alan Turing Gets Channeled in a New Opera, Josh, Jones,, 16 January 2017, 25 July 2017,

In literature

  • In William Gibson's Neuromancer the Turing police have jurisdiction over AIs. (1984)WEB,weblink Science Fiction, 24 November 1985, The New York Times, 25 September 2016,
  • Turing is featured in the Neal Stephenson novel Cryptonomicon (1999).WEB,weblink Click Here, 25 September 2016,
  • The 2000 Doctor Who novel The Turing Test features Turing and the writer Graham Greene."Turing Test", BBC, 24 October 2014.
  • The 2006 novel A Madman Dreams of Turing Machines contrasts fictionalised accounts of the lives and ideas of Turing and Kurt Gödel.{{citation|title=Obsessive-Genius Disorder|journal=The New York Times|first=Jim|last=Holt|date=3 September 2006|url=}}.
  • The 2009 novel Fall of Man in Wilmslow by David Lagercrantz is a fictional account of the investigation of Alan Turing’s death written from the point of view of the investigating police officer.NEWS, Hopley, Claire, BOOK REVIEW: 'Fall of Man in Wilmslow',weblink The Washington Times, 13 July 2016, 20 June 2019,
  • The 2015 novel Speak, written by Louisa Hall, includes a series of fictional letters written from Turing to his best friend's mother throughout his life, detailing his research about artificial intelligence.NEWS, Review: 'Speak' by Louisa Hall,weblink Chicago Tribune, 31 January 2016, NEWS, Waldman, Katy, 'Speak,' by Louisa Hall,weblink The New York Times, 31 January 2016,
  • In the graphic novel series Ãœber, in which a fictionalised version of WWII plays out involving superhuman soldiers called "Tank-Men", Turing is one of the researchers as well as a Tank-Man himself.WEB, Truitt, Brian, 'Uber' explores monsters and men of World War II,weblink USA Today, 13 April 2017,
  • Turing is featured in Ian McEwan's 2019 novel, Machines Like Me {{ISBN|978-1787331662}}.

In music

  • Electronic music duo Matmos released an EP titled For Alan Turing in 2006, which was based on material commissioned by Dr. Robert Osserman and David Elsenbud of the Mathematical Sciences Research Institute.WEB,weblink Matmos release For Alan Turing, Vague Terrain, 5 February 2015, In one of its tracks, an original Enigma Machine is sampled.WEB,weblink Track Review: Matmos â€“ Enigma Machine For Alan Turing, Sheppard, Justin, 7 September 2006, Prefix Mag, 5 February 2015,
  • In 2012, Spanish group Hidrogenesse dedicated their LP Un dígito binario dudoso. Recital para Alan Turing (A dubious binary digit. Concert for Alan Turing) to the memory of the mathematician.WEB,weblink Hidrogenesse, 'Un dígito binario dudoso', Rodríguez Ramos, Javier, 29 May 2012, El País â€“ Cultura, Spanish, 5 February 2015,
  • A musical work inspired by Turing's life, written by Neil Tennant and Chris Lowe of the Pet Shop Boys, entitled A Man from the Future, was announced in late 2013.WEB,weblink Pet Shop Boys Working on Alan Turing Project, Portwood, Jerry, 13 September 2012, Out magazine, 29 December 2013, It was performed by the Pet Shop Boys and Juliet Stevenson (narrator), the BBC Singers, and the BBC Concert Orchestra conducted by Dominic Wheeler at the BBC Proms in the Royal Albert Hall on 23 July 2014.WEB,weblink BBC Radio 3 â€“ BBC Proms, 2014 Season, Prom 8: Pet Shop Boys, BBC, 1 November 2014,
  • Codebreaker is also the title of a choral work by the composer James McCarthy. It includes settings of texts by the poets Wilfred Owen, Sara Teasdale, Walt Whitman, Oscar Wilde and Robert Burns that are used to illustrate aspects of Turing's life. It was premiered on 26 April 2014 at the Barbican Centre in London, where it was performed by the Hertfordshire Chorus, who commissioned the work, led by David Temple with the soprano soloist Naomi Harvey providing the voice of Turing's mother.WEB, Hertfordshire Chorus â€“ James McCarthy: Codebreaker, a life in music,weblink Classical Music Magazine, 14 November 2014, {{YouTube|SRMNi4_th-0|Codebreaker}}

In film

  • Codebreaker, original UK title Britain's Greatest Codebreaker, is a TV film that aired on 21 November 2011 by Channel 4 about Turing's life. It had a limited release in the US beginning on 17 October 2012. The story is told as a discussion between Turing and his psychiatrist Dr. Franz Greenbaum. The story is based on journals maintained by Greenbaum and others who have studied Turing's life as well as some of his colleagues.WEB,weblink Britain's Greatest Codebreaker: the tragic story of Alan Turing, Chris Harvey, The Daily Telegraph, 10 January 2015,
  • The historical drama film The Imitation Game, directed by Morten Tyldum and starring Benedict Cumberbatch as Turing and Keira Knightley as Joan Clarke, was released in the UK on 14 November 2014 and released theatrically in the US on 28 November 2014. The story concentrates on the period of Turing’s life where he breaks the Enigma code with other codebreakers in Bletchley Park.WEB, Brooks, Brian, 'The Imitation Game' Will Stuff Theaters This Holiday Weekend â€“ Specialty Box Office Preview,weblink Deadline, NEWS, Charles, McGrath, The Riddle Who Unlocked the Enigma â€“ 'The Imitation Game' Dramatises the Story of Alan Turing,weblink 30 October 2014, The New York Times, 2 November 2014, WEB,weblink The Imitation Game: the queerest thing to hit multiplexes for years?, Walters, Ben, 9 October 2014, 14 November 2014, The Guardian, WEB,weblink The Imitation Game review â€“ Cumberbatch cracks biopic code, Bradshaw, Peter, 13 November 2014, 14 November 2014, The Guardian, It received the Academy Award for Best Adapted Screenplay in 2015. It was a tremendous success, bringing in $233.6 millionWEB,weblink The Imitation Game (2014) - Box Office Mojo,, 2018-12-27, for a production cost of $14 million.WEB,weblink How The Weinstein Co. Turned 'Imitation Game' Director Into an Oscar Contender, The Hollywood Reporter, en, 2018-12-27,

See also




  • BOOK, Agar, Jon, Turing and the Universal Machine, Duxford, Icon, 2001, 978-1-84046-250-0, harv,
  • BOOK, Agar, Jon, The government machine: a revolutionary history of the computer, MIT Press, 2003, Cambridge, Massachusetts, 978-0-262-01202-7,
  • JOURNAL, Alexander, C. Hugh O'D., Conel Hugh O'Donel Alexander (circa 1945), Cryptographic History of Work on the German Naval Enigma,weblink The National Archives, Kew, Reference HW 25/1, {{harvid, Alexander, circa 1945, }}
  • BOOK, Beavers, Anthony, S. Barry, Cooper, Jan, van Leeuwen, Alan Turing: His Work and Impact, Elsevier, Waltham, 2013, 481–485, Alan Turing: Mathematical Mechanist, 978-0-12-386980-7,weblink harv,
  • BOOK, Beniger, James, James R. Beniger, The control revolution: technological and economic origins of the information society, Harvard University Press, 1986, Cambridge, Massachusetts, 978-0-674-16986-9, The control revolution: technological and economic origins of the information society,
  • BOOK, Babbage, Charles, Charles Babbage, 1864

, 2008, Campbell-Kelly, Martin, Martin Campbell-Kelly, Passages from the life of a philosopher, Rough Draft Printing, 978-1-60386-092-5, harv,
  • BOOK, Bodanis, David, David Bodanis, Electric Universe: How Electricity Switched on the Modern World, 2005, Three Rivers Press, New York, 978-0-307-33598-2, 61684223,
  • Bruderer, Herbert: Konrad Zuse und die Schweiz. Wer hat den Computer erfunden? Charles Babbage, Alan Turing und John von Neumann Oldenbourg Verlag, München 2012, XXVI, 224 Seiten, {{isbn|978-3-486-71366-4}}
  • BOOK, Campbell-Kelly, Martin, Martin Campbell-Kelly, Aspray, William, Computer: A History of the Information Machine, Basic Books, 1996, New York, 978-0-465-02989-1,weblink
  • BOOK, Ceruzzi, Paul E., Paul E. Ceruzzi, A History of Modern Computing, MIT Press, 1998, Cambridge, Massachusetts, and London, 978-0-262-53169-6,
  • BOOK, Chandler, Alfred, Alfred D. Chandler Jr., The Visible Hand: The Managerial Revolution in American Business, Belknap Press, 1977, Cambridge, Massachusetts, 978-0-674-94052-9,weblink
  • JOURNAL, Church, Alonzo, Alonzo Church, An Unsolvable Problem of Elementary Number Theory, American Journal of Mathematics, 58, 2, 1936, 345–363, 0002-9327, 10.2307/2371045, harv, 2371045,
  • BOOK, Cooper, S. Barry, van Leeuwen, Jan, Alan Turing: His Work and Impact, 2013, New York, Elsevier, 978-0-12-386980-7, harv,
  • JOURNAL, Copeland, B. Jack, Jack Copeland, Colossus: Its Origins and Originators, IEEE Annals of the History of Computing, 26, 4, 38–45, 2004a, 10.1109/MAHC.2004.26, harv,
  • BOOK, Copeland, B. Jack, The Essential Turing, 2004b, Oxford University Press, Oxford, 978-0-19-825079-1, 156728127, harv,
  • BOOK, Copeland, B. Jack, Alan Turing's Automatic Computing Engine, 2005, Oxford University Press, Oxford, 978-0-19-856593-2, 224640979,
  • BOOK, Copeland, B. Jack, Colossus: The secrets of Bletchley Park's code-breaking computers, 2006, Oxford University Press, 978-0-19-284055-4, harv,
    • BOOK, Hilton, Peter, Peter Hilton, 2006, Living with Fish: Breaking Tunny in the Newmanry and Testery, harv, Colussus, in {{Harvnb|Copeland|2006|pp=189–203}}
  • BOOK, Edwards, Paul N, The closed world: computers and the politics of discourse in Cold War America, MIT Press, 1996, Cambridge, Massachusetts, 978-0-262-55028-4,
  • BOOK, Gannon, Paul, Colossus: Bletchley Park's Greatest Secret, London, Atlantic Books, 2006, 2007, 978-1-84354-331-2, harv,
  • BOOK, Hodges, Andrew, Andrew Hodges, Alan Turing : the enigma, London, Burnett Books, 978-0-09-152130-1, 1983, harv,
  • BOOK, Hochhuth, Rolf, Rolf Hochhuth, Alan Turing: en berättelse, Symposion, 1988, 978-91-7868-109-9,
  • BOOK, Leavitt, David, David Leavitt, 2007, The man who knew too much: Alan Turing and the invention of the computer, Phoenix, 978-0-7538-2200-5, harv,
  • BOOK, Levin, Janna, Janna Levin, A Madman Dreams of Turing Machines, Knopf, 2006, New York, 978-1-4000-3240-2,
  • BOOK, Lewin, Ronald, Ronald Lewin, Ultra Goes to War: The Secret Story, Classic Penguin, Classic Military History, 1978, 2001, Hutchinson & Co, London, 978-1-56649-231-7, harv,
  • BOOK, Lubar, Steven, 1993, Infoculture, Boston, Massachusetts and New York, Houghton Mifflin, 978-0-395-57042-5,weblink
  • JOURNAL, Mahon, A.P., The History of Hut Eight 1939–1945, UK National Archives Reference HW 25/2, 1945,weblink 10 December 2009, harv,
  • BOOK, Oakley, Brian, Brian Oakley, The Bletchley Park War Diaries: July 1939 â€“ August 1945, Wynne Press, 2006, 2.6, harv,
  • JOURNAL, O'Connell, H, Fitzgerald, M, Did Alan Turing have Asperger's syndrome?, Irish Journal of Psychological Medicine, 20, 28–31, Irish Institute of Psychological Medicine, 2003, 0790-9667, harv, 10.1017/s0790966700007503,
  • {{MacTutor Biography|id=Turing|title=Alan Mathison Turing}}
  • Petzold, Charles (2008). "The Annotated Turing: A Guided Tour through Alan Turing's Historic Paper on Computability and the Turing Machine". Indianapolis: Wiley Publishing. {{isbn|978-0-470-22905-7}}
  • Smith, Roger (1997). Fontana History of the Human Sciences. London: Fontana.
  • BOOK, Sipser, Michael, Introduction to the Theory of Computation, PWS Publishing, 978-0-534-95097-2, 2006, harv,
  • Weizenbaum, Joseph (1976). Computer Power and Human Reason. London: W.H. Freeman. {{isbn|0-7167-0463-3}}
  • NEWS, Turing, A.M., 1937, On Computable Numbers, with an Application to the Entscheidungsproblem, Delivered to the Society November 1936, Proceedings of the London Mathematical Society, 2, 42, 230–65, 10.1112/plms/s2-42.1.230,weblink harv, and NEWS, Turing, A.M., 1937, On Computable Numbers, with an Application to the Entscheidungsproblem: A correction, Proceedings of the London Mathematical Society, 2, 43, 544–46, 10.1112/plms/s2-43.6.544, 1938,
  • BOOK, Turing, Sara Stoney, Alan M Turing, W Heffer, 1959, Turing's mother, who survived him by many years, wrote this 157-page biography of her son, glorifying his life. It was published in 1959, and so could not cover his war work. Scarcely 300 copies were sold (Sara Turing to Lyn Newman, 1967, Library of St John's College, Cambridge). The six-page foreword by Lyn Irvine includes reminiscences and is more frequently quoted. It was re-published by Cambridge University Press in 2012, to honour the centenary of his birth, and included a new foreword by Martin Davis, as well as a never-before-published memoir by Turing's older brother John F. Turing.
  • BOOK, Whitemore, Hugh, Hugh Whitemore, Hodges, Andrew, Andrew Hodges, Breaking the code, S. French, 1988, This 1986 Hugh Whitemore play tells the story of Turing's life and death. In the original West End and Broadway runs, Derek Jacobi played Turing and he recreated the role in a 1997 television film based on the play made jointly by the BBC and WGBH, Boston. The play is published by Amber Lane Press, Oxford, ASIN: B000B7TM0Q
  • Williams, Michael R. (1985) A History of Computing Technology, Englewood Cliffs, New Jersey: Prentice-Hall, {{isbn|0-8186-7739-2}}
  • BOOK, Yates, David M., Turing's Legacy: A history of computing at the National Physical Laboratory 1945–1995, 1997, Science Museum, London, London Science Museum, London, 978-0-901805-94-2, 123794619,

Further reading



  • {{Citation |last= Bernhardt |first= Chris |title= Turing's Vision: The Birth of Computer Science |publisher= MIT Press |year= 2017 |isbn= 978-0-262-53351-5 }}
  • BOOK, Jack Copeland, Copeland, B. Jack, Jonathan Bowen, Bowen, Jonathan P., Robin Wilson (mathematician), Wilson, Robin, Sprevak, Mark, The Turing Guide, Oxford University Press, 2017, 978-0-19-874783-3, The Turing Guide,
  • BOOK, Turing's Cathedral: The Origins of the Digital Universe, George Dyson (science historian), George, Dyson, 978-1-4000-7599-7, 2012, Vintage,
  • BOOK, James Gleick, Gleick, James, The Information: A History, a Theory, a Flood, New York, Pantheon, 2011, 978-0-375-42372-7, The Information: A History, a Theory, a Flood,
  • BOOK, Alan Turing: The Enigma, 2014, Andrew, Hodges, Andrew Hodges, Princeton University Press, 978-0-691-16472-4, (originally published in 1983); basis of the film The Imitation Game

External links

{{Commons category|Alan Turing}} {{FRS 1951}}{{Timelines of computing}}{{Use dmy dates|date=November 2017}}{{EngvarB|date=November 2017}}{{Good article}}{{Authority control}}

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