Alan_Turing

{{Infobox Person
| name = Alan Turing
| image = Alan Turing.jpg
| image_size = 220x242px
| caption =
| birth_name = Alan Mathison Turing
| birth_date = {{Birth date|1912|6|23|df=yes}}
| birth_place = [[London]], [[England]]
| death_date = {{Death date and age|1954|6|7|1912|6|23|df=yes}}
| death_place = [[Wilmslow]], [[Cheshire]], [[England]]
| death_cause = [[Cyanide]] ([[suicide]])
| resting_place =
| resting_place_coordinates =
| residence =
| nationality = [[England|English]]
| other_names =
| known_for =
| education = [[King's College, Cambridge]] [[Princeton University]], [[Doctor of Philosophy|Ph.D.]]
| employer =
| occupation = [[Mathematician]], [[Logician]], [[Cryptographer]]
| title = [[Order of the British Empire]] [[Fellow of the Royal Society]]
| salary =
| networth =
| height =
| weight =
| term =
| predecessor =
| successor =
| party =
| boards =
| religion =
| spouse =
| partner =
| children =
| parents = Julius Mathison Turing Ethel Stoney Turing
| relatives =
| signature =
| website = [http://www.alanturing.net/ AlanTuring.net] [http://www.turingarchive.org/ Turing Digital Archive] [http://www.turing.org.uk/turing/ Biographer]
| footnotes =
}}
'''Alan Mathison Turing''', [[Order of the British Empire|OBE]], [[Fellow of the Royal Society|FRS]] ({{pronEng|ˈtjʊərɪŋ}}, [[23 June]] [[1912]] – [[7 June]] [[1954]]) was an [[England|English]] [[mathematician]], [[logician]], and [[cryptographer]].

Turing is often considered to be the father of modern [[computer science]]. Turing provided an influential formalisation of the concept of the [[algorithm]] and computation with the [[Turing machine]]. With the [[Turing test]], he made a significant and characteristically provocative contribution to the debate regarding [[artificial intelligence]]: whether it will ever be possible to say that a machine is [[consciousness|conscious]] and can [[thought|think]]. He later worked at the [[National Physical Laboratory, UK|National Physical Laboratory]], creating one of the first designs for a stored-program computer, although it was never actually built. In 1948 he moved to the [[Victoria University of Manchester|University of Manchester]] to work on the [[Manchester Mark I]], then emerging as one of the world's earliest true computers.

During the [[World War II|Second World War]] Turing worked at [[Bletchley Park]], Britain's [[cryptanalysis|codebreaking]] centre, and was for a time head of [[Hut 8]], the section responsible for [[Germany|German]] naval cryptanalysis. He devised a number of techniques for breaking German ciphers, including the method of the [[bombe]], an electromechanical machine that could find settings for the [[Enigma machine]].

In 1952, Turing was convicted of "acts of gross indecency" after admitting to a sexual relationship with a man in Manchester. He was placed on probation and required to undergo [[estrogen]] therapy to achieve temporary [[chemical castration]].<ref name="hodges1983" /> Turing died after eating an apple laced with [[cyanide]] in 1954. His death was ruled a suicide.

== Childhood and youth ==
Turing was conceived in 1911 in [[Chhatrapur]], [[Orissa]], [[India]].<ref>Hodges, 1983, p. 5</ref> His father, Julius Mathison Turing, was a member of the [[Indian Civil Service]]. Julius and wife Sara (''née'' Stoney; 1881 – 1976, daughter of Edward Waller Stoney, chief engineer of the Madras Railways) wanted Alan to be brought up in [[England]], so they returned to [[Maida Vale]],<ref name="englishheritaget">{{cite web |url=http://www.english-heritage.org.uk/server/show/nav.001002006005/chooseLetter/T |title=London Blue Plaques |accessdate=2007-02-10 |format= |work=English-Heritage.org.uk }}</ref> [[London]], where Alan Turing was born [[23 June]] [[1912]], as recorded by a [[blue plaque]] on the outside of the building, now the Colonnade Hotel.<ref name="hodges1983">{{cite book |last=Hodges |first=Andrew |authorlink= |coauthors= |title=Alan Turing: The Enigma |year=1983 |publisher=Simon & Schuster |location=New York |isbn=0-671-49207-1 |pages=pp. 5 }}</ref><ref name="turingorguk>{{cite web | url=http://www.turing.org.uk/turing/scrapbook/memorial.html | title=The Alan Turing Internet Scrapbook | accessdate=2006-09-26}}</ref> He had an elder brother, John. His father's civil service commission was still active, and during Turing's childhood years his parents travelled between [[Guildford]], England and India, leaving their two sons to stay with friends in England. Very early in life, Turing showed signs of the genius he was to display more prominently later.<ref name=toolbox>{{cite web |title=Alan Turing - Towards a Digital Mind: Part 1 |first=G. James |last=Jones |date=[[2001-12-11]] |url=http://www.systemtoolbox.com/article.php?history_id=3 |accessdate=2007-07-27 |work=[[System Toolbox]]}}</ref>

His parents enrolled him at St Michael's, a day school, at the age of six. The headmistress recognised his genius early on, as did many of his subsequent educators. In 1926, at the age of 14, he went on to [[Sherborne School]] in [[Dorset]]. His first day of term coincided with [[UK General Strike of 1926|General Strike]] in England, but so determined was he to attend his first day that he rode his bike unaccompanied more than 60 miles from [[Southampton]] to school, stopping overnight at an inn.<ref name=metamagical>{{cite book |title=Metamagical Themas: Questing for the Essence of Mind and Pattern |first=Douglas R. |last=Hofstadter |year=1985 |publisher=Basic Books |isbn=0465045669}}</ref>

Turing's natural inclination toward mathematics and science did not earn him respect with the teachers at Sherborne, a famous and expensive [[public school (England)|public school]], whose definition of education placed more emphasis on the [[classics]]. His headmaster wrote to his parents: "I hope he will not fall between two schools. 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".<ref>Hodges, 1983, p. 26</ref>

Despite this, Turing continued to show remarkable ability in the studies he loved, solving advanced problems in 1927 without having even studied elementary [[calculus]]. In 1928, aged 16, Turing encountered [[Albert Einstein]]'s work; not only did he grasp it, but he extrapolated Einstein's questioning of [[Newton's laws of motion]] from a text in which this was never made explicit.<ref>Hodges, 1983, p. 34</ref>

[[Image:KingsCollegeChapel.jpg|thumb|The computer room at King's is now named after Turing, who became a student there in 1931 and a Fellow in 1935.]]

Turing's hopes and ambitions at school were raised by his strong feelings for his best friend Christopher Morcom, with whom he fell in love, though the feeling was not reciprocated. Morcom died suddenly only a few weeks into their last term at Sherborne, from complications of [[bovine]] [[tuberculosis]], contracted after drinking infected cow's milk as a boy.<ref name=teuscher>** {{cite book |last=Teuscher |first=Christof (ed.) |authorlink=Christof Teuscher |coauthors= |title=Alan Turing: Life and Legacy of a Great Thinker |year=2004 |publisher=[[Springer Science+Business Media|Springer-Verlag]] |location= |isbn=3-540-20020-7 }}</ref>

== University and his work on computability ==
Turing's unwillingness to work as hard on his classical studies as on science and mathematics meant he failed to win a scholarship to [[Trinity College, Cambridge]], and went on to the college of his second choice, [[King's College, Cambridge]]. He was an undergraduate there from 1931 to 1934, graduating with a distinguished degree, and in 1935 was elected a fellow at King's on the strength of a dissertation on the [[central limit theorem]].

In his momentous paper "On Computable Numbers, with an Application to the ''[[Entscheidungsproblem]]''" (submitted on [[28 May]] [[1936]]), Turing reformulated [[Kurt Gödel]]'s 1931 results on the limits of proof and computation, replacing Gödel's universal arithmetic-based formal language with what are now called [[Turing machine]]s, formal and simple devices. He proved that such a machine would be capable of performing any conceivable mathematical problem if it were representable as an [[algorithm]], even if no actual Turing machine would be likely to have practical applications, being much slower than alternatives.

Turing machines are to this day the central object of study in [[computation|theory of computation]]. He went on to prove that there was no solution to the ''Entscheidungsproblem'' by first showing that the [[halting problem]] for Turing machines is [[Decision problem|undecidable]]: it is not possible to decide, in general, algorithmically whether a given Turing machine will ever halt. While his proof was published subsequent to [[Alonzo Church]]'s equivalent proof in respect to his [[lambda calculus]], Turing's work is considerably more accessible and intuitive. It was also novel in its notion of a "Universal (Turing) Machine", the idea that such a machine could perform the tasks of any other machine. The paper also introduces the notion of [[definable number]]s.

Most of 1937 and 1938 he spent at [[Princeton University]], studying under [[Alonzo Church]]. In 1938 he obtained his [[Doctor of Philosophy|Ph.D.]] from Princeton; his dissertation introduced the notion of relative computing where Turing machines are augmented with so-called [[oracle machine|oracles]], allowing a study of problems that cannot be solved by a Turing machine.

Back in Cambridge in 1939, he attended lectures by [[Ludwig Wittgenstein]] about the [[foundations of mathematics]].<ref>Hodges, 1983, p. 152</ref> The two argued and disagreed, with Turing defending [[Formalism (mathematics)|formalism]] and Wittgenstein arguing that mathematics is overvalued and does not discover any absolute truths.<ref>Hodges, 1983, pp. 153-154</ref>

== Cryptanalysis ==
[[Image:Turing flat.jpg|thumb|Two cottages in the stable yard at Bletchley Park. Turing worked here from 1939 – 1940 until he moved to Hut 8.]]
During the [[Second World War]], Turing was a main participant in the efforts at [[Bletchley Park]] to break German ciphers. Building on cryptanalysis work carried out in [[Poland]] before the war, he contributed several insights into breaking both the [[Enigma machine]] and the [[Lorenz SZ 40/42]] (a teletype cipher attachment codenamed "Tunny" by the British), and was, for a time, head of [[Hut 8]], the section responsible for reading [[Germany|German]] naval signals.

Since September 1938, Turing had been working part-time for the [[Government Code and Cypher School]] (GCCS), the British codebreaking organization. He worked on the problem of the German Enigma machine, and collaborated with [[Dilly Knox]], a senior GCCS codebreaker.<ref>Jack Copeland, "Colossus and the Dawning of the Computer Age", p. 352 in ''Action This Day'', 2001</ref> On [[4 September]] [[1939]], the day after Britain declared war on Germany, Turing reported to Bletchley Park, the wartime station of GCCS.<ref name="copeland2006">{{cite book |last=Copeland (ed.)|first=B. Jack |authorlink= |coauthors= |title=Colossus: The Secrets of Bletchley Park's Codebreaking Computers |year=2006 |publisher=Oxford University Press |location=New York |isbn=019284055X |pages=p. 378 }}</ref>

[[Image:Bombe-rebuild.jpg|thumbnail|Replica of a bombe machine]]
===The Turing-Welchman bombe===
Within weeks of arriving at Bletchley Park,<ref name="copeland2006" /> Turing had designed an electromechanical machine which could help break Enigma: the [[bombe]], named after and building upon the original Polish-designed ''[[Bomba (cryptography)|bomba]]''. They were also referred to as "Bronze Goddesses" because their cases were made of bronze, but they were more prosaically described by operators as being "like great big metal bookcases".<ref>Mary Stewart, 'Bombe' Operator, interviewed in "The Men Who Cracked Enigma", UKTV History Channel documentary series "Heroes of World War II", 2003</ref> 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-protected message traffic.

Professor [[I.J. Good|Jack Good]], cryptanalyst working at the time with Turing at Bletchley Park, later said: "Turing's most important contribution, I ''think'', was of part of the design of the bombe, the cryptanalytic machine. He had the idea that you could use, in effect, a theorem in logic which sounds to the untrained ear rather absurd; namely that from a contradiction, you can deduce ''everything.''"<ref>"The Men Who Cracked Enigma", 2003</ref>

The bombe searched for possibly correct settings used for an Enigma message (ie, rotor order, rotor settings, etc), and used a suitable "[[crib (cryptanalysis)|crib]]": a fragment of probable [[plaintext]]. For each possible setting of the rotors (which had of the order of 1019 states, or 1022 for the U-Boat Enigmas which eventually had four rotors, compared to the usual Enigma variant's three<ref>Professor Jack Good in "The Men Who Cracked Enigma", 2003: with his caveat: "if my memory is correct"</ref>), the bombe performed a chain of logical deductions based on the crib, implemented electrically. The bombe detected when a contradiction had occurred, and ruled out that setting, moving onto the next. Most of the possible settings would cause contradictions and be discarded, leaving only a few to be investigated in detail. Turing's bombe was first installed on [[18 March]] [[1940]].<ref>Hodges, 1983, p. 191</ref> Over 200 bombes were in operation by the end of the war.<ref name=codebreaker>{{cite web |title=Alan Turing, Codebreaker and Computer Pioneer |last=Copeland |first=Jack |coauthors=Diane Proudfoot |date=May, 2004 |url=http://www.alanturing.net/turing_archive/pages/Reference%20Articles/codebreaker.html |accessdate=2007-07-27}}</ref>

===Hut 8 and Naval Enigma===
In December 1940, Turing solved the naval Enigma indicator system, which was more complex than the indicator systems used by the other services. Turing also invented a [[Bayes' theorem|Bayesian]] statistical technique termed "[[Banburismus]]" to assist in breaking Naval Enigma. Banburismus could rule out certain orders of the Enigma rotors, reducing time needed to test settings on the bombes.

In the spring of 1941, Turing proposed marriage to Hut 8 co-worker Joan Clarke, although the engagement was broken off by mutual agreement in the summer.

In July 1942, Turing devised a technique termed ''Turingismus'' or ''Turingery'' for use against the Lorenz cipher used in the Germans' new Geheimschreiber machine ("secret writer") which was one of those codenamed "Fish". He also introduced the Fish 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 simpler prior machine (including the "Heath Robinson") and whose superior speed allowed the brute-force decryption techniques to be applied usefully to the daily-changing cyphers.<ref>Copeland, 2006, pp. 72</ref> A frequent misconception is that Turing was a key figure in the design of Colossus; this was not the case.<ref>Copeland, 2006, pp. 382-383</ref>

Turing travelled to the United States in November 1942 and worked with US Navy cryptanalysts on Naval Enigma and bombe construction in Washington, and assisted at [[Bell Labs]] with the development of [[secure speech]] devices. He returned to Bletchley Park in March 1943. During his absence, [[Conel Hugh O'Donel Alexander|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.

In the latter part of the war, while teaching himself electronics at the same time, and assisted by engineer [[Donald Bayley]], Turing undertook the design of a portable machine codenamed ''[[Delilah (secure speech)|Delilah]]'' to allow [[secure voice]] communications. It was intended for different applications, lacking capability for use with long-distance radio transmissions, and in any case Delilah was completed too late to be used during the war. Though Turing demonstrated it to officials by encrypting/decrypting a recording of a [[Winston Churchill]] speech, Delilah was not adopted for use.

In 1945, Turing was awarded the [[Order of the British Empire|OBE]] for his wartime services, but his work remained secret for many years. A biography published by the Royal Society shortly after his death recorded:

:"Three remarkable papers written just before the war, on three diverse mathematical subjects, show the quality of the work that might have been produced if he had settled down to work on some big problem at that critical time. For his work at the Foreign Office he was awarded the OBE."<ref name="royalsocbio">{{cite book |last=Newman |first=M. H. A. |authorlink= |coauthors= |title=Alan Mathison Turing |year=1955 |publisher=The Royal Society |location= |isbn= |series=Biographical Memoirs of Fellows of the Royal Society, 1955, Volume 1 }}</ref>

== Early computers and the Turing Test ==
From 1945 to 1947 he was at the [[National Physical Laboratory, UK|National Physical Laboratory]], where he worked on the design of the [[ACE (computer)|ACE]] (Automatic Computing Engine). He presented a paper on [[19 February]] [[1946]], which was the first complete design of a [[Von Neumann architecture|stored-program computer]] in Britain. Although he succeeded in designing the ACE, there were delays in starting the project and he became disillusioned. In late 1947 he returned to Cambridge for a sabbatical year. While he was at Cambridge, ACE was completed in his absence and executed its first program on [[10 May]] [[1950]]. In 1948 he was appointed Reader in the [[School of Mathematics, University of Manchester|Mathematics Department]] at [[Victoria University of Manchester|Manchester]] and in 1949 became deputy director of the computing laboratory at the [[Victoria University of Manchester|University of Manchester]], and worked on software for one of the earliest true computers — the [[Manchester Mark I]]. During this time he continued to do more abstract work, and in "[[Computing machinery and intelligence]]" (Mind, October 1950), Turing addressed the problem of [[artificial intelligence]], and proposed an experiment now known as the [[Turing test]], an attempt to define a standard for a machine to be called "sentient".

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. In 1952, lacking a computer powerful enough to execute the program, Turing played a game in which he simulated the computer, taking about half an hour per move. [http://www.chessgames.com/perl/chessgame?gid=1356927 The game] was recorded; the program lost to Turing's colleague [[Alick Glennie]], although it is said that it won a game against Champernowne's wife.

== Pattern formation and mathematical biology ==
Turing worked from 1952 until his death in 1954 on [[mathematical biology]], specifically [[morphogenesis]]. He published one paper on the subject called "The Chemical Basis of Morphogenesis" in 1952, putting forth the Turing hypothesis of pattern formation.[http://www.sciencedaily.com/releases/2006/11/061128093244.htm] His central interest in the field was understanding [[Leonardo of Pisa|Fibonacci]] [[phyllotaxis]], the existence of [[Fibonacci number]]s in plant structures. He used [[reaction-diffusion equation]]s which are now central to the field of [[pattern formation]]. Later papers went unpublished until 1992 when ''Collected Works of A.M. Turing'' was published.

== Prosecution for homosexual acts and Turing's death ==
Turing was [[homosexual]]<ref name="hodges1983" /> in a period when homosexual acts were illegal in Britain and homosexuality was regarded as a [[mental illness]] and subject to criminal sanctions. In 1952, Arnold Murray, a 19-year-old recent acquaintance of his,<ref>cf. Hodges, pp.449-455</ref> helped an accomplice to break into Turing's house, and Turing went to the police to report the crime. As a result of the police investigation, Turing acknowledged a sexual relationship with Murray, and a crime having been identified and settled, they were charged with gross indecency under [[Criminal Law Amendment Act of 1885#Section 11|Section 11]] of the Criminal Law Amendment Act of 1885. Turing was unrepentant and was convicted. He was given the choice between imprisonment and probation, conditional on his undergoing [[hormone|hormonal]] [[chemical castration|treatment]] designed to reduce [[libido]]. In order to avoid going to jail, he accepted the [[estrogen|oestrogen]] hormone injections, which lasted for a year, with side effects including [[gynecomastia]] (breast enlargement). His conviction led to a removal of his security clearance and prevented him from continuing consultancy for [[GCHQ]] on cryptographic matters.

On [[8 June]] [[1954]], his cleaner found him dead; the previous day, he had died of [[cyanide]] [[poison]]ing, apparently from a cyanide-laced apple he left half-eaten beside his bed. The apple itself was never tested for contamination with cyanide, and cyanide poisoning as a cause of death was established by a post-mortem. Most believe that his death was intentional, and the death was ruled a [[suicide]]. His mother, however, strenuously argued that the ingestion was accidental due to his careless storage of laboratory chemicals. Biographer Andrew Hodges suggests that Turing may have killed himself in this ambiguous way quite deliberately, to give his mother some [[plausible deniability]].<ref>Hodges, 1983, pp. 488-489</ref> Others suggest that Turing was reenacting a scene from "[[Snow White]]", his favourite fairy tale.<ref>Ferris, Timothy. ''Seeing in the Dark''. 2002. p. 250</ref> Because Turing's homosexuality would have been perceived as a security risk, the possibility of assassination has also been suggested.<ref name="leavitt">{{cite book |last=Leavitt |first=David |authorlink=David Leavitt |coauthors= |title= The man who knew too much: Alan Turing and the invention of the computer |year=2006 |publisher=W. W. Norton |location=New York |isbn=0393052362 }}</ref> His remains were cremated at [[Woking]] crematorium on [[12 June]] [[1954]].

== Posthumous recognition ==
Since 1966, the [[Turing Award]] has been given annually by the [[Association for Computing Machinery]] to a person for technical contributions to the computing community. It is widely considered to be the computing world's equivalent to the [[Nobel Prize]].

Various tributes to Turing have been made in Manchester, the city where he worked towards the end of his life. In 1994 a stretch of the [[Manchester]] city inner ring road was named Alan Turing Way.
[[Image:Alan Turing Memorial Closer.jpg|left|thumbnail|Alan Turing memorial statue in [[Whitworth Gardens|Sackville Park]]]]
A [[Alan Turing Memorial|statue of Turing]] was unveiled in [[Manchester]]  on [[23 June]] [[2001]]. It is in [[Sackville Park]], between the [[University of Manchester]] building on Whitworth Street and the [[Canal Street, Manchester|Canal Street]] '[[gay village]]'. A celebration of Turing's life and achievements arranged by the [[British Logic Colloquium]] and the [[British Society for the History of Mathematics]] was held on [[5 June]] [[2004]] at the [[Victoria University of Manchester|University of Manchester]] and the [[Alan Turing Institute]] was initiated in the university that summer. The building housing the [[School of Mathematics, University of Manchester|School of Mathematics]], the Photon Sciences Institute, and the [[Jodrell Bank Centre for Astrophysics]] is named the ''[[Alan Turing Building]]'' and was opened in July 2007.

On [[23 June]] [[1998]], on what would have been Turing's 86th birthday, [[Andrew Hodges]], his biographer, unveiled an official [[English Heritage]] [[Blue Plaque]] on his childhood home in Warrington Crescent, [[London]], now the Colonnade hotel.<ref>{{cite web | url=http://www.turing.org.uk/bio/oration.html | title=Unveiling the official Blue Plaque on Alan Turing's Birthplace | accessdate=2006-09-26}}</ref><ref>{{cite web | url=http://www.blueplaque.com/detail.php?plaque_id=348 | title=About this Plaque - Alan Turing | accessdate=2006-09-25}}</ref>
To mark the 50th anniversary of his death, a memorial plaque was unveiled on [[7 June]] [[2004]] at his former residence, Hollymeade, in Wilmslow.
[[Image:Turing Plaque.jpg|thumbnail|Plaque marking Turing's home]]

For his achievements in computing, various universities have honoured him. On [[28 October]] [[2004]] a bronze statue of Alan Turing sculpted by [[John W Mills]] was unveiled at the [[University of Surrey]].<ref name="univsurrey">{{cite web |url=http://portal.surrey.ac.uk/press/oct2004/281004a/ |title=The Earl of Wessex unveils statue of Alan Turing |accessdate=2007-02-10 |format= |work= }}</ref> The statue marks the 50th anniversary of Turing's death. It portrays Turing carrying his books across the campus. The [[Polytechnic University of Puerto Rico]] and
Los Andes University of Bogotá, Colombia, both have computer laboratories named after Turing.
The [[University of Texas at Austin]] has an honours computer science program named the [[Turing Scholars]].
[[Istanbul Bilgi University]] organizes an annual conference on the theory of computation called Turing Days.<ref name="bilgiuniv">{{cite web |url=http://cs.bilgi.edu.tr/pages/turing_days/ |title=Turing Days @ İstanbul Bilgi University |accessdate=2007-02-10 |format= |work= }}</ref> [[University of Cambridge|Cambridge University]] has a computer lab in [[King's College, Cambridge]] named the "Turing Room".
[[Carnegie Mellon University]] has a granite bench, situated in The Hornbostel Mall, with the name "A. M. Turing" carved across the top, "Read" down the left leg, and "Write" down the other.
The [[Boston, Massachusetts|Boston]] [[GLBT pride]] organization named Turing their 2006 Honorary Grand Marshal.<ref name="bostonpride">{{cite web |url=http://www.bostonpride.org/honorarymarshal.php |title=Honorary Grand Marshal |accessdate=2007-02-10 |format= |work= }}</ref>

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 late American billionaire [[Sidney Frank]].<ref>[http://www.bletchleypark.org.uk/news/docview.rhtm/454075/article.html Bletchley Park Unveils Statue Commemorating Alan Turing], Bletchley Park press release, [[20 June]] 2007]</ref>

The Turing Relay<ref>[http://www.turingrelay.co.uk/ Turing Trail Relay]</ref> is a six-stage relay race on riverside footpaths from [[Ely]] to Cambridge and back to Ely. These paths were used for running by Turing while at Cambridge; his marathon best time was 2 hours, 46 minutes.

== Turing in fiction==

* In the 1996 documentary ''Breaking the code'' Turing is portrayed by [[Derek Jacobi]].
* Physicist [[Janna Levin]]'s novel ''[[A Madman Dreams of Turing Machines]]'' focuses on the lives of both Alan Turing and [[Kurt Gödel]].
* In the 1989 ''[[Doctor Who]]'' serial ''[[The Curse of Fenric]]'', the character of Dr Judson is based on Turing. Turing himself is a narrator of the [[Doctor Who spin-offs#Original fiction|''Doctor Who'' spin-off]] [[Eighth Doctor Adventures|novel]] ''[[The Turing Test (novel)|The Turing Test]]'' by [[Paul Leonard]]. An Alan Turing from a [[parallel universe (fiction)|parallel universe]] appears in the later novel ''[[The Domino Effect (novel)|The Domino Effect]]'' by [[David Bishop]].
* [[Greg Egan]]'s novella, ''[http://gregegan.customer.netspace.net.au/MISC/ORACLE/Oracle.html Oracle]'', is about an alternate universe version of Turing.
* In [[William Gibson]]'s seminal [[cyberpunk]] novel ''[[Neuromancer]]'', the sinister body tasked with the regulation and suppression of artificial intelligences is called the "Turing Registry", and its agents are referred to as the "[[Turing Police]]".
* In 1987 German author and playwright [[Rolf Hochhuth]] published the novel ''Alan Turing'' after reading the biography written by Turing's mother.
* [[Neal Stephenson]]'s novel [[Cryptonomicon]] features Turing as a supporting character.
* The protagonist of [[Robert Harris (novelist)|Robert Harris]]'s novel ''[[Enigma (novel)|Enigma]]'' and the [[Enigma (2001 film)|film]] made from it is arguably based upon Turing.
* [[Alastair Reynolds]] novels make frequent mention of the 'Turing Test' as a measure of machine sentience.

== Further reading ==
{{Refbegin}}
* Agar, Jon (2002). ''The Government Machine''. [[Cambridge, Massachusetts|Cambridge]], [[Massachusetts]]: The [[MIT Press]]. ISBN 0262012022
* Beniger, James (1986). ''The Control Revolution: Technological and Economic Origins of the Information Society''. [[Cambridge, Massachusetts|Cambridge]], [[Massachusetts]]: [[Harvard University Press]]. ISBN 0674169867
* {{cite book |last=Bodanis |first=David |authorlink= |coauthors= |title=Electric Universe: How Electricity Switched on the Modern World |year=2005 |publisher=Three Rivers Press |location=New York |isbn=0-307-33598-4 }}
* Campbell-Kelly, Martin (ed.) (1994). ''Passages in the Life of a Philosopher''. [[London]]: William Pickering. ISBN 0813520665
* Campbell-Kelly, Martin, and Aspray, William (1996). ''Computer: A History of the Information Machine''. [[New York]]: Basic Books. ISBN 0-465-02989-2
* Ceruzzi, Paul (1998). ''A History of Modern Computing''. [[Cambridge, Massachusetts|Cambridge]], [[Massachusetts]], and [[London]]: [[MIT Press]]. ISBN 0-262-53169-0
* Chandler, Alfred (1977). ''The Visible Hand: The Managerial Revolution in American Business''. [[Cambridge]], [[Massachusetts]]: [[Belknap Press]]. ISBN 0674940520
* {{cite journal |last=Copeland |first=B. Jack |authorlink=B. Jack Copeland |title=Colossus: Its Origins and Originators |journal=[[IEEE Annals of the History of Computing]] |volume=26 | issue=4 |pages=38 — 45 | publisher= | date=2004 | url= }}
* {{cite book |last=Copeland |first=B. Jack (ed.) |authorlink=B. Jack Copeland |coauthors= |title=The Essential Turing |year=2004 |publisher=Oxford University Press |location=Oxford |isbn=0-19-825079-7 }}
* {{cite book |last=Copeland (ed.) |first=B. Jack |authorlink=B. Jack Copeland |coauthors= |title=Alan Turing's Automatic Computing Engine |year=2005 |publisher=Oxford University Press |location=Oxford |isbn=0-19-856593-3 }}
* Edwards, Paul N (1996). ''The Closed World''. [[Cambridge]], [[Massachusetts]]: [[MIT Press]]. ISBN 0262550288
* Hodges, Andrew (1983). ''Alan Turing: The Enigma of Intelligence''. [[London]]: Burnett Books. ISBN 0045100608
* Hochhuth, Rolf. ''Alan Turing''
* Leavitt, David (2006) "The Man Who Knew Too Much - Alan Turing and the invention of the computer" Orion Books ltd ISBN 9780753822005
* Lubar, Steven (1993) ''Infoculture''. [[Boston]] and [[New York]]: [[Houghton Mifflin]]. ISBN 039557045
* {{MacTutor Biography|id=Turing|title=Alan Mathison Turing}}
* Smith, Roger (1997). ''Fontana History of the Human Sciences''. [[London]]: Fontana.
* Weizenbaum, Joseph (1976). ''Computer Power and Human Reason''. [[London]]: W.H. Freeman. ISBN 0716704633
* Williams, Michael R. (1985). ''A History of Computing Technology''. [[Englewood Cliffs]], [[New Jersey]]: [[Prentice-Hall]]. ISBN 0-8186-7739-2
* {{cite book |last=Yates |first=David M. |authorlink= |coauthors= |title=Turing's Legacy: A history of computing at the National Physical Laboratory 1945 – 1995 |year=1997 |publisher=[[Science Museum, London|London Science Museum]] |location=[[London]] |isbn=0-901805-94-7 }}
* Turing's mother, Sara Turing, who survived him by many years, wrote a biography of her son glorifying his life. Published in 1959, it could not cover his war work; scarcely 300 copies were sold.<ref name="saraturing"> Sara Turing to Lyn Newman, 1967, Library of [[St John's College, Cambridge]].</ref> The six-page foreword by [[Lyn Irvine]] includes reminiscences and is more frequently quoted.
* ''Breaking the Code'' is a 1986 play by [[Hugh Whitemore]], telling the story of Turing's life and death. In the original [[West End theatre|West End]] and [[Broadway theatre|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|WGBH, Boston]].The play is published by Amber Lane Press, [[Oxford]]. ASIN: B000B7TM0Q

{{Refend}}

== See also ==
* [[Alan Turing's Unorganized Machines]]
* [[Good-Turing frequency estimation]]
* [[Philosophy of information]]

==References==
{{reflist|2}}

==External links==
{{wikiquote}}
{{commonscat|Alan Turing}}
* {{MacTutor Biography|id=Turing}}
* [http://www.turing.org.uk/ Alan Turing] site maintained by Andrew Hodges including a [http://www.turing.org.uk/bio/part1.html short biography]
* [http://www.alanturing.net/ AlanTuring.net Turing Archive for the History of Computing] by Jack Copeland
* [http://www.turingarchive.org The Turing Archive] - contains scans of some unpublished documents and material from the Kings College archive
* [http://www.systemtoolbox.com/article.php?history_id=3 Alan Turing — Towards a Digital Mind: Part 1]
* [http://www.time.com/time/time100/scientist/profile/turing.html Time 100:Alan Turing]
* [http://plato.stanford.edu/entries/turing/ Stanford Encyclopedia of Philosophy entry]
* {{Find A Grave|id=12651680|name=Alan Mathison Turing}}

===Papers===
* [http://bibnetwiki.org/wiki/Category:Alan_M._Turing_Paper An extensive list of Turing's papers, reports and lectures, plus translated versions and collections ]
* [http://www.loebner.net/Prizef/TuringArticle.html "Computing machinery and intelligence"]
* Turing's paper titled [http://www.thocp.net/biographies/papers/turing_oncomputablenumbers_1936.pdf "On Computable Numbers with an Application to the Entscheidungsproblem"] (PDF)

{{portalpar|Logic}}

{{Persondata
|NAME=Turing, Alan Mathison
|ALTERNATIVE NAMES=
|SHORT DESCRIPTION=[[Computer scientist]], [[mathematician]], and [[cryptographer]]
|DATE OF BIRTH={{birth date|1912|6|23|mf=y}}
|PLACE OF BIRTH=[[Paddington]], [[London]], [[England]]
|DATE OF DEATH={{death date|1954|6|7|mf=y}}
|PLACE OF DEATH=[[Manchester]], [[England]]
}}
{{DEFAULTSORT:Turing, Alan}}
[[Category:Alan Turing| ]]
[[Category:20th century mathematicians]]
[[Category:20th century philosophers]]
[[Category:English mathematicians]]
[[Category:Artificial intelligence researchers]]
[[Category:British cryptographers]]
[[Category:Computer designers]]
[[Category:Computer pioneers]]
[[Category:English computer scientists]]
[[Category:English inventors]]
[[Category:English philosophers]]
[[Category:Formal methods people]]
[[Category:Philosophers of mind]]
[[Category:People associated with Bletchley Park]]
[[Category:British people of World War II]]
[[Category:Academics of the University of Manchester]]
[[Category:Fellows of the Royal Society]]
[[Category:English atheists]]
[[Category:People prosecuted under anti-homosexuality laws]]
[[Category:Alumni of King's College, Cambridge]]
[[Category:Princeton University alumni]]
[[Category:Old Shirburnians]]
[[Category:Members of the Order of the British Empire]]
[[Category:LGBT people from England]]
[[Category:Scientists who committed suicide]]
[[Category:Mathematicians who committed suicide]]
[[Category:Suicides by poison]]
[[Category:Cause of death disputed]]
[[Category:1912 births]]
[[Category:1954 deaths]]
[[Category:History of artificial intelligence]]

{{Link FA|es}}
[[af:Alan Turing]]
[[ar:آلان تورنج]]
[[ast:Alan Turing]]
[[az:Alan Turinq]]
[[bn:অ্যালান টুরিং]]
[[bs:Alan Turing]]
[[br:Alan Turing]]
[[bg:Алън Тюринг]]
[[ca:Alan Turing]]
[[cs:Alan Turing]]
[[cy:Alan Turing]]
[[da:Alan Turing]]
[[de:Alan Turing]]
[[et:Alan Turing]]
[[el:Άλαν Τούρινγκ]]
[[es:Alan Mathison Turing]]
[[eo:Alan Turing]]
[[eu:Alan Turing]]
[[fa:آلن تورینگ]]
[[fr:Alan Turing]]
[[ga:Alan Turing]]
[[gl:Alan Turing]]
[[ko:앨런 튜링]]
[[hi:एलेन ट्यूरिंग]]
[[hr:Alan Turing]]
[[io:Alan Turing]]
[[id:Alan Turing]]
[[is:Alan Turing]]
[[it:Alan Turing]]
[[he:אלן טיורינג]]
[[ku:Alan Turing]]
[[lv:Alans Tjūrings]]
[[lb:Alan M. Turing]]
[[lt:Alanas Tiuringas]]
[[li:Alan Turing]]
[[hu:Alan Turing]]
[[mk:Алан Тјуринг]]
[[mt:Alan Turing]]
[[mr:ऍलन ट्युरिंग]]
[[ms:Alan Turing]]
[[nl:Alan Turing]]
[[ja:アラン・チューリング]]
[[no:Alan Turing]]
[[nn:Alan Turing]]
[[pl:Alan Mathison Turing]]
[[pt:Alan Turing]]
[[ro:Alan Turing]]
[[ru:Тьюринг, Алан Матисон]]
[[scn:Alan Turing]]
[[simple:Alan Turing]]
[[sk:Alan Mathison Turing]]
[[sl:Alan Turing]]
[[sr:Алан Тјуринг]]
[[sh:Alan Turing]]
[[fi:Alan Turing]]
[[sv:Alan Turing]]
[[te:అలాన్ ట్యూరింగ్‌]]
[[th:แอลัน ทัวริง]]
[[vi:Alan Turing]]
[[tg:Алан Тюринг]]
[[tr:Alan Turing]]
[[uk:Тюрінг Алан Матісон]]
[[zh:艾伦·麦席森·图灵]]