Who was Alan Turing?

Founder of computer science, mathematician, philosopher,
codebreaker, strange visionary and a gay man before his time:

...a quite brilliant mathematician... whose unique contribution helped to turn the tide of war... horrifying that he was treated so inhumanely...

Personal statement of apology by the Prime Minister, Gordon Brown, 10 September 2009.

1912 (23 June): Birth, Paddington, London
1926-31: Sherborne School
1930: Death of friend Christopher Morcom
1931-34: Undergraduate at King's College, Cambridge University
1932-35: Quantum mechanics, probability, logic
1935: Elected fellow of King's College, Cambridge
1936: The Turing machine, computability, universal machine
1936-38: Princeton University. Ph.D. Logic, algebra, number theory
1938-39: Return to Cambridge. Introduced to German Enigma cipher machine
1939-40: The Bombe, machine for Enigma decryption
1939-42: Breaking of U-boat Enigma, saving battle of the Atlantic
1943-45: Chief Anglo-American crypto consultant. Electronic work.
1945: National Physical Laboratory, London
1946: Computer and software design leading the world.
1947-48: Programming, neural nets, and artificial intelligence
1948: Manchester University
1949: First serious mathematical use of a computer
1950: The Turing Test for machine intelligence
1951: Elected FRS. Non-linear theory of biological growth
1952: Arrested as a homosexual, loss of security clearance
1953-54: Unfinished work in biology and physics
1954 (7 June): Death (suicide) by cyanide poisoning, Wilmslow, Cheshire.

The Inspiration of Life and Death, 1928-1932

Another boy

In 1928 Alan Turing was allowed to enter the sixth form of Sherborne School and to specialise in mathematics and science. In the Science Sixth he met Christopher Morcom, another outstanding student and enthusiast for science. 

Alan Turing

Christopher Morcom

Alan Mathison Turing, OBE, FRS (pronounced /'tj??r??/, TYOOR-ing; 23 June 1912 – 7 June 1954), was an English mathematician, logician, cryptanalyst, and computer scientist. He was influential in the development of computer science and provided an influential formalisation of the concept of the algorithm and computation with the Turing machine. In 1999 Time Magazine named Turing as one of the 100 Most Important People of the 20th Century for his role in the creation of the modern computer.^[1] His Turing test was a significant and characteristically provocative contribution to the debate regarding artificial intelligence.^{[citation needed]}

During the Second World War, Turing worked for the Government Code and Cypher School at Bletchley Park, Britain's codebreaking centre. For a time he was head of Hut 8, the section responsible for 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. After the war he worked at the National Physical Laboratory, where he created one of the first designs for a stored-program computer, the ACE.

Towards the end of his life Turing became interested in chemistry. He wrote a paper on the chemical basis of morphogenesis,^[2] and he predicted oscillating chemical reactions such as the Belousov–Zhabotinsky reaction, which were first observed in the 1960s.

Turing's homosexuality, illegal and considered to be a mental illness during his lifetime, resulted in a criminal prosecution in 1952. He accepted treatment with female hormones as an alternative to going to prison. He died in 1954, several weeks before his 42nd birthday, from an apparently self-administered cyanide poisoning, although his mother (and some others) considered the circumstances of his death to be suspicious.^{[citation needed]}

On 10 September 2009, following an Internet campaign, British Prime Minister Gordon Brown made an official public apology on behalf of the British government for the way in which Turing was treated after the war.^[3]

Cryptanalysis

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 by Marian Rejewski, Jerzy Rózycki and Henryk Zygalski from Cipher Bureau 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 German naval signals.

Since September 1938, Turing had been working part-time for the Government Code and Cypher School (GCCS), the British code breaking organisation. He worked on the problem of the German Enigma machine, and collaborated with Dilly Knox, a senior GCCS codebreaker.^[19] On 4 September 1939, the day after the UK declared war on Germany, Turing reported to Bletchley Park, the wartime station of GCCS.[20

Turing–Welchman bombe

Within weeks of arriving at Bletchley Park,^[20] Turing had designed an electromechanical machine which could help break Enigma faster than bomba from 1932, the bombe, named after and building upon the original Polish-designed bomba. 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 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." ^[21]

The bombe searched for possibly correct settings used for an Enigma message (i.e., rotor order, rotor settings, etc.), and used a suitable "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),^[22] 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.^[23] Over two hundred bombes were in operation by the end of the war.^[24]

Hut 8 and Naval Enigma

In December 1940, Turing solved the naval Enigma indicator system, which was more mathematically complex than the indicator systems used by the other services. Turing also invented a 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.^{[citation needed]}

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 machines (including the "Heath Robinson") and whose superior speed allowed the brute-force decryption techniques to be applied usefully to the daily-changing cyphers. ^[25] A frequent misconception is that Turing was a key figure in the design of Colossus; this was not the case.^[26] While working at Bletchley, Turing, a talented long-distance runner, occasionally ran the 40 miles to London when he was needed for high-level meetings.^[27]

Turing travelled to the United States in November 1942 and worked with U.S. 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, 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 he moved to work at Hanslope Park, where he further developed his knowledge of electronics with the assistance of engineer Donald Bailey. Together they undertook the design and construction of a portable secure voice communications machine codenamed Delilah.^[28] 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 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.

—Newman, M. H. A. (1955). Alan Mathison Turing. Biographical Memoirs of Fellows of the Royal Society, 1955, Volume 1. The Royal Society. 

Early computers and the Turing test

From 1945 to 1947 he was at the National Physical Laboratory, where he worked on the design of the ACE (Automatic Computing Engine). He presented a paper on 19 February 1946, which was the first detailed design of a stored-program computer.^[29] 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. While he was at Cambridge, the Pilot ACE was built in his absence. It executed its first program on 10 May 1950.

In 1948 he was appointed Reader in the Mathematics Department at Manchester. In 1949 he became deputy director of the computing laboratory at the University of Manchester, and worked on software for one of the earliest stored-program computers—the Manchester Mark 1. 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 "intelligent". The idea was that a computer could be said to "think" if it could fool an interrogator into thinking that the conversation was with a human. 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.^{[citation needed]}

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. The game was recorded.^[30] 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.^[31] His central interest in the field was understanding Fibonacci phyllotaxis, the existence of Fibonacci numbers in plant structures. He used reaction–diffusion equations 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.

Conviction for gross indecency

In January 1952 Turing picked up 19-year-old Arnold Murray outside a cinema in Manchester. After a lunch date, Turing invited Murray to spend the weekend with him at his house, an invitation which Murray accepted although he did not show up. The pair met again in Manchester the following Monday, when Murray agreed to accompany Turing to the latter's house. A few weeks later Murray visited Turing's house again, and apparently spent the night there.^[32]

After Murray helped an accomplice to break into his house, Turing reported the crime to the police. During the investigation Turing acknowledged a sexual relationship with Murray. Homosexual acts were illegal in the United Kingdom at that time,^[6] and so both were charged with gross indecency under Section 11 of the Criminal Law Amendment Act 1885, the same crime that Oscar Wilde had been convicted of more than fifty years earlier.^[33]

Turing was given a choice between imprisonment or probation conditional on his agreement to undergo hormonal treatment designed to reduce libido. He accepted chemical castration via oestrogen hormone injections,^[34] which lasted for a year. One of the known side effects of these hormone injections was the development of breasts, known as gynecomastia, something which plagued Turing for the rest of his life.^{[citation needed]}

Turing's conviction led to the removal of his security clearance, and barred him from continuing with his cryptographic consultancy for GCHQ. At the time, there was acute public anxiety about spies and homosexual entrapment by Soviet agents, due to the recent exposure of the first two members of the Cambridge Five, Guy Burgess and Donald Maclean, as KGB double agents. Turing was never accused of espionage but, as with all who had worked at Bletchley Park, was prevented from discussing his war work.^{[citation needed]}

Death

On 8 June 1954, Turing's cleaner found him dead; he had died the previous day, apparently killed by a cyanide-laced apple he left half-eaten beside his bed. A post-mortem examination established that the cause of death was cyanide poisoning, although the apple was not tested for cyanide.^[35] An inquest determined that he had committed suicide, and he was cremated at Woking crematorium on 12 June 1954.

Turing's 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.^[36] Others suggest that Turing was re-enacting a scene from Snow White, his favourite fairy tale.^[37]

Because Turing's homosexuality was perceived as a security risk, the possibility of assassination has also been suggested.^[38] Assassination theorists point out that Turing's British passport was not revoked after his conviction, although he was denied entry to the United States. He was still free to teach mathematics and to travel to other European countries, which he did many times.

Legacy

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.^[39]

Breaking the Code is a 1986 play by Hugh Whitemore about Alan Turing. The play ran in London's West End beginning in November 1986 and on Broadway from 15 November 1987 to 10 April 1988. There was also a 1996 BBC television production. In all cases, Derek Jacobi played Turing. 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.

Tributes

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 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. It is in Sackville Park, between the University of Manchester building on Whitworth Street and the 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 University of Manchester; the Alan Turing Institute was initiated in the university that summer. The building housing the School of Mathematics, the Photon Science 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 at his birthplace and childhood home in Warrington Crescent, London, now the Colonnade hotel.^[40][41] 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.

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 in Guildford.^[42] The statue marks the 50th anniversary of Turing's death.

It portrays him carrying his books across the campus. Turing Road in the University's Research Park predates this.

A building in the School of Technology at Oxford Brookes University is called the Turing Building.

The Polytechnic University of Puerto Rico and Los Andes University in Bogotá, Colombia, both have computer laboratories named after Turing, and Aarhus University in Århus, Denmark, similarly has a building named in his honour. The University of Texas at Austin has an honours computer science programme named the Turing Scholars.^[43] Istanbul Bilgi University organises an annual conference on the theory of computation called Turing Days.^[44] The computer room in King's College, Cambridge, is named the "Turing Room" after him. 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 GLBT pride organisation named Turing their 2006 Honorary Grand Marshal.^[45]

On 13 March 2000, St Vincent & The Grenadines issued a set of stamps to celebrate the greatest achievements of the twentieth century, one of which carries a recognisable portrait of Turing against a background of repeated 0s and 1s, and is captioned '1937: Alan Turing's theory of digital computing'.

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.^[46]

The Turing Relay^[47] is a six-stage relay race on riverside footpaths from Ely to Cambridge and back. These paths were used for running by Turing while at Cambridge; his marathon best time was 2 hours, 46 minutes.^[48] The marathon world best time in the early 1940s was in the region of 2 hours, 25 minutes.

In August 2009, John Graham-Cumming started a petition urging the British Government to posthumously apologise to Alan Turing for prosecuting him as a homosexual.^[49][50] The petition received thousands of signatures.^[51][52] Prime Minister Gordon Brown acknowledged the petition, releasing a statement on 10 September 2009 describing Turing's treatment as "appalling":^[51][53]

Thousands of people have come together to demand justice for Alan Turing and recognition of the appalling way he was treated. While Turing was dealt with under the law of the time and we can't put the clock back, his treatment was of course utterly unfair and I am pleased to have the chance to say how deeply sorry I and we all are for what happened to him. [...] So on behalf of the British government, and all those who live freely thanks to Alan's work I am very proud to say: we're sorry, you deserved so much better.^[51]

See Also

• Unorganized machine
• Good–Turing frequency estimation
• Philosophy of information
• Turing Award
• Turing Machine
• Turing test
• Turing Days
• Turing degree
• Turing switch
• Alan Turing Year
• Ludwig Wittgenstein
• Philosophy of mathematics

References

1. ^ Gray, Paul (1999-03-29). "Time 100: Alan Turing". Time.com. http://www.time.com/time/time100/scientist/profile/turing.html. Retrieved 2009-06-18. 
2. ^ A.M. Turing, "The Chemical Basis of Morphogenesis", Philosophical Transactions of The Royal Society of London, series B, volume 237, pages 37–72, 1952.
3. ^ BBC coverage of Gordon Brown's apology for Turing's mistreatment by the British Government
4. ^ Hodges, 1983, p. 5
5. ^ "London Blue Plaques". English-Heritage.org.uk. http://www.english-heritage.org.uk/server/show/nav.001002006005/chooseLetter/T. Retrieved 2007-02-10. 
6. ^ ^{a b} Hodges, Andrew (1983). Alan Turing: The Enigma. New York: Simon & Schuster. p. 5. ISBN 0-671-49207-1. 
7. ^ "The Alan Turing Internet Scrapbook". http://www.turing.org.uk/turing/scrapbook/memorial.html. Retrieved 2006-09-26. 
8. ^ "Hastings Blue Plaque Trail". http://www.hastingshandbook.co.uk/Archive/HHMar08/FMar08_AlanTuring.shtml. Retrieved 2008-08-10. 
9. ^ Jones, G. James (2001-12-11). "Alan Turing - Towards a Digital Mind: Part 1". System Toolbox. http://www.systemtoolbox.com/article.php?history_id=3. Retrieved 2007-07-27. 
10. ^ Hofstadter, Douglas R. (1985). Metamagical Themas: Questing for the Essence of Mind and Pattern. Basic Books. ISBN 0-465-04566-9. OCLC 230812136. 
11. ^ Hodges, 1983, p. 26
12. ^ Hodges, 1983, p. 34
13. ^ ** Teuscher, Christof (ed.) (2004). Alan Turing: Life and Legacy of a Great Thinker. Springer-Verlag. ISBN 3-540-20020-7. OCLC 53434737 62339998. 
14. ^ Paul Gray, "Alan Turing", Time Magazine's Most Important People of the Century, p.2 [1]
15. ^ Turing, A.M. (1936), "On Computable Numbers, with an Application to the Entscheidungsproblem", Proceedings of the London Mathematical Society, 2 42: 230–65, 1937, doi:10.1112/plms/s2-42.1.230, http://www.comlab.ox.ac.uk/activities/ieg/e-library/sources/tp2-ie.pdf  (and Turing, A.M. (1938), "On Computable Numbers, with an Application to the Entscheidungsproblem: A correction", Proceedings of the London Mathematical Society, 2 43: 544–6, 1937, doi:10.1112/plms/s2-43.6.544 )
16. ^ Hodges, 1983, p. 138
17. ^ Hodges, 1983, p. 152
18. ^ Hodges, 1983, pp. 153–154
19. ^ Jack Copeland, "Colossus and the Dawning of the Computer Age", p. 352 in Action This Day, 2001
20. ^ ^{a b} Copeland, 2006 p. 378
21. ^ "The Men Who Cracked Enigma", Episode 4 in the UKTV History Channel documentary series "Heroes of World War II"
22. ^ Professor Jack Good in "The Men Who Cracked Enigma", 2003: with his caveat: "if my memory is correct"
23. ^ Hodges, 1983, p. 191.
24. ^ Copeland, Jack; Diane Proudfoot (May 2004). "Alan Turing, Codebreaker and Computer Pioneer". http://www.alanturing.net/turing_archive/pages/Reference%20Articles/codebreaker.html. Retrieved 2007-07-27.

1. ^ Copeland, 2006, p. 72.
2. ^ Copeland, 2006, pp. 382, 383.
3. ^ Bodyguard of Lies, by Anthony Cave Brown, 1975.
4. ^ Hodges, 1983, p. 270
5. ^ Copeland, 2006, p. 108.
6. ^ Alan Turing vs Alick Glennie (1952) "Turing Test"
7. ^ "Control Mechanism For Biological Pattern Formation Decoded" in ScienceDaily (Nov. 30, 2006)
8. ^ Leavitt 2007, p. 266
9. ^ Leavitt 2007, p. 268
10. ^ Turing, Alan (1912–1954)
11. ^ Hodges, 1983, p488
12. ^ Hodges, 1983, pp. 488, 489
13. ^ Ferris, Timothy. Seeing in the Dark (2002), p. 250
14. ^ Leavitt, David (2006). The man who knew too much: Alan Turing and the invention of the computer. New York: W. W. Norton. ISBN 0-393-05236-2. OCLC 233002606 60742103. 
15. ^ Steven Geringer (27 July 2007). "ACM'S Turing Award Prize Raised To $250,000". ACM press release. http://www.acm.org/press-room/news-releases-2007/turingaward/. Retrieved 2008-10-16. 
16. ^ "Unveiling the official Blue Plaque on Alan Turing's Birthplace". http://www.turing.org.uk/bio/oration.html. Retrieved 2006-09-26. 
17. ^ "About this Plaque - Alan Turing". Archived from the original on 2007-10-13. http://web.archive.org/web/20071013143212/http://www.blueplaque.com/detail.php?plaque_id=348. Retrieved 2006-09-25. 
18. ^ "The Earl of Wessex unveils statue of Alan Turing". http://portal.surrey.ac.uk/press/oct2004/281004a/. Retrieved 2007-02-10. 
19. ^ "Turing Scholars Program at the University of Texas at Austin". http://www.cs.utexas.edu/academics/undergraduate/honors/turing/. Retrieved 2009-08-16. 
20. ^ "Turing Days @ Istanbul Bilgi University". http://cs.bilgi.edu.tr/pages/turing_days/. Retrieved 2007-02-10. 
21. ^ "Honorary Grand Marshal". http://www.bostonpride.org/honorarymarshal.php. Retrieved 2007-02-10. 
22. ^ Bletchley Park Unveils Statue Commemorating Alan Turing, Bletchley Park press release, 20 June 2007
23. ^ Turing Trail Relay
24. ^ The Alan Turing Internet Scrapbook: Alan Turing: world class distance runner
25. ^ Thousands call for Turing apology, BBC News, 31 August 2009, http://news.bbc.co.uk/2/hi/technology/8226509.stm, retrieved 2009-08-31 
26. ^ Petition seeks apology for Enigma code-breaker Turing, CNN, 01 September 2009, http://www.cnn.com/2009/WORLD/europe/09/01/alan.turing.petition/index.html, retrieved 2009-09-01 
27. ^ ^{a b c} Treatment of Alan Turing was "appalling", Number10.gov.uk, 10 September 2009, http://www.number10.gov.uk/Page20571 
28. ^ The petition was only open to UK citizens.
29. ^ "PM apology after Turing petition". BBC News. 11 September 2009. http://news.bbc.co.uk/2/hi/technology/8249792.stm. Retrieved 2009-09-11.

Further reading

• Levin, Janna (2006). A Madman Dreams of Turing Machines. New York, New York: Knopf. ISBN 978-1400032402
• Agar, Jon (2002). The Government Machine. Cambridge, Massachusetts: The MIT Press. ISBN 0-262-01202-2
• Beniger, James (1986). The Control Revolution: Technological and Economic Origins of the Information Society. Cambridge, Massachusetts: Harvard University Press. ISBN 0-674-16986-7
• Bodanis, David (2005). Electric Universe: How Electricity Switched on the Modern World. New York: Three Rivers Press. ISBN 0-307-33598-4. OCLC 61684223. 
• Campbell-Kelly, Martin (ed.) (1994). Passages in the Life of a Philosopher. London: William Pickering. ISBN 0-8135-2066-5
• 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, 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 0-674-94052-0
• Copeland, B. Jack (2004). "Colossus: Its Origins and Originators". IEEE Annals of the History of Computing 26 (4): 38 – 45. doi:10.1109/MAHC.2004.26. 
• Copeland, B. Jack (ed.) (2004). The Essential Turing. Oxford: Oxford University Press. ISBN 0-19-825079-7. OCLC 156728127 224173329 48931664 57434580 57530137 59399569. 
• Copeland (ed.), B. Jack (2005). Alan Turing's Automatic Computing Engine. Oxford: Oxford University Press. ISBN 0-19-856593-3. OCLC 224640979 56539230. 
• B. Jack Copeland and others ; edited by B. Jack Copeland. (2006), Copeland, B. Jack, ed., Colossus: The Secrets of Bletchley Park's Codebreaking Computers, Oxford: Oxford University Press, ISBN 978-0-19-284055-4, OCLC 238755360 51315364 62179172 
• Edwards, Paul N (1996). The Closed World. Cambridge, Massachusetts: MIT

• Press. ISBN 0-262-55028-8
• Hodges, Andrew (1983). Alan Turing: The Enigma of Intelligence. London: Burnett Books. ISBN 0-04-510060-8
• Hochhuth, Rolf. Alan Turing
• Leavitt, David (2007), The Man Who Knew Too Much; Alan Turing and the invention of the computer, Phoenix, ISBN 978-0-7538-2200-5 
• Lubar, Steven (1993) Infoculture. Boston and New York: Houghton Mifflin. ISBN 0-395-57042-5
• O'Connor, John J.; Robertson, Edmund F., "Alan Mathison Turing", MacTutor History of Mathematics archive .
• 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.
• Weizenbaum, Joseph (1976). Computer Power and Human Reason. London: W.H. Freeman. ISBN 0-7167-0463-3
• Williams, Michael R. (1985). A History of Computing Technology. Englewood Cliffs, New Jersey: Prentice-Hall. ISBN 0-8186-7739-2
• Yates, David M. (1997). Turing's Legacy: A history of computing at the National Physical Laboratory 1945 – 1995. London: London Science Museum. ISBN 0-901805-94-7. OCLC 123794619 40624091. 
• 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 (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.
• Breaking the Code is a 1986 play by Hugh Whitemore, telling 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

External links

• Alan Turing site maintained by Andrew Hodges including a short biography
• Alan Turing at the Mathematics Genealogy Project
• Alan Turing – Towards a Digital Mind: Part 1
• Alan Turing at Find a Grave
• AlanTuring.net – Turing Archive for the History of Computing by Jack Copeland
• O'Connor, John J.; Robertson, Edmund F., "Alan Turing", MacTutor History of Mathematics archive .
• Stanford Encyclopedia of Philosophy entry
• The Turing Archive – contains scans of some unpublished documents and material from the Kings College archive
• Time 100:Alan Turing
• Alan Turing in the RKBExplorer
• The Mind and the Computing Machine a 1949 discussion of Alan Turing and others
• Alan Turing Year website
• CiE 2012: Turing Centenary Conference website

Papers

• An extensive list of Turing's papers, reports and lectures, plus translated versions and collections
• Turing, Alan (October 1950), "Computing Machinery and Intelligence", Mind LIX (236): 433–460, doi:10.1093/mind/LIX.236.433, ISSN 0026-4423, http://loebner.net/Prizef/TuringArticle.html, retrieved 2008-08-18

The Alan Turing Internet Scrapbook

The Scrapbook has 22 pages full of images and links. Go to the Scrapbook Index or go direct to one of the most popular starting-points:
Empire of the mind, 1912-1928
Turing Machines, with Turing Machines simulated in JavaScript
Critical cryptanalysis: the Enigma war
Who invented the computer? and The world class distance runner
The Turing Test in theory... and the Turing (Sex) Test in practice.
Breaking the Code: Alan Turing on stage and screen

Philosophy Area

Thinking about thinking:
Alan Turing, minds, machines and life

thinking by Andrew Hodges
author of Alan Turing: the enigma

Was Alan Turing a philosopher?

Alan Turing would probably have laughed at the idea of being called a great philosopher, or any kind of philosopher. He called himself a mathematician. But his 1950 paper Computing Machinery and Intelligence  has become one of the most cited in modern philosophical literature and people are always arguing about it. This is because he brought the new and rigorous mathematical concept of computability to bear on traditional problems of mind and body, free-will and determinism.

Alan Turing did not think small. Along with the origin of universe, and the origin of life, the question of how 'mind' arises in 'matter' is one of the greatest scientific problems. And it involves the questions about freedom and responsibility that people worry about in every aspect of life.

Am I a philosopher?

No. But Ray Monk, whose biography of Wittgenstein was influenced a bit by Alan Turing: the enigma, invited me to contribute to a series called The Great Philosophers.

There were some thoughts in this book that didn't appear in my earlier biography Alan Turing: the enigma. The main stimulus was the influence of Roger Penrose's books The emperor's new mind and Shadows of the mind. This passage on the influence of the war, for instance, showed the way my thinking had developed since 1983.

Turing in the Land of NZ

Alan Turing's life and work touches on many difficult and controversial subjects so I expect criticism. I was rather surprised, however, by the arguments of two philosophers from New Zealand, Copeland and Proudfoot, who reviewed my work in the Times Literary Supplement.

In April 1999 the philosophers published their extraordinary views on Turing's so-called 'Forgotten ideas' in an article in Scientific American. 

Comment on Copeland and Proudfoot's Oracle

An unexpected result was I found I had more to say about the philosophy of mind and machines than I had realised before.

Here is a lecture, first given at Hamburg in 2000, with the title:

Uncomputability in the work of Alan Turing and Roger Penrose

I was invited by Professor Ed Zalta, the editor of the on-line Stanford Encyclopedia of Philosophy, to submit an entry on Turing's life and thought.

My article 'Alan Turing' in the Stanford Encyclopedia

And in June 2002 I gave a talk which ended the proceedings of the Turing Day at the Federal Institute of Technology, Lausanne, Switzerland.

See my illustrated talk on: What would Alan Turing have done after 1954?

Logical and Physical

In Alan Turing: the enigma I had chosen a formal structure of 'logical' and 'physical' life, with a 'bridge passage' set in 1942-43, and I think this was a good point of departure. When Mike Yates edited the last volume of the Turing Collected Works, he asked me to write a piece on The nature of Turing and the physical world which is also on this site, and I now have a number of other publications which reflect on this theme.

Browse my Publications page.

The ideas can probably be taken yet further. My own attitude is that there is something to learn from every discussion, and I am used to a culture in mathematical physics where people are always having to reshape and adapt their ideas in the light of new insights. Alan Turing himself was basically an applied mathematician, and that's the spirit in which I approach his ideas. Although I don't agree with Copeland and Proudfoot's conclusions, they have stimulated worthwhile new questions — mainly about how Turing's work relates in fine detail to what is usually called the physical Church-Turing thesis. Also, Copeland noticed one sentence in Turing's 1951 radio talk where he mentioned a problem about quantum mechanics. This is in fact just the objection to Artificial Intelligence theory that Roger Penrose developed into a big new theory in his books. This is all to the good, and I don't mind at all saying that I wish I had noticed this earlier myself!

I am not so keen on philosophers' way of taking up a 'position' and attacking everyone else's, as if it were shameful ever to develop one's views. People argue a great deal about 'Church's thesis' as if it were frozen in time as a dogma. Yes, the historical questions are very interesting, but it might be more interesting to see whether there is a 'Church's synthesis', where logic and physics develop together to give something quite new. This means knowing something about mathematics and physics, not just chopping texts into words.

My detailed review of Copeland's work appears in a special issue of the Notices of the American Mathematical Society. It is available on-line in .pdf form.

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Philosophy of Life: Innocence and Experience

In my work I have always wanted to keep in mind Alan Turing as a lively human being, and arid philosophical argument tends to turn him into an textual 'Turing' that I tried to avoid. In addition, his dramatic life and personality continue to raise questions related to moral and political philosophy.

Two publications have more about the moral themes of Alan Turing's extraordinary life as a gay man at the heart of the Anglo-American military machine: Turing — a Cambridge scientific mind and The military use of Alan Turing.

In August 2003 I gave a talk on Alan Turing at Imperial War Museum North. This also formed part of the programme of the lesbian and gay Europride. An article based on my talk, which was designed to link themes of war, sexuality, and science, appears here:

• Alan Turing: an enigma after fifty years

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You can also see an illustrated webpage version of my talk on the Turing Collection of screenprints by the distinguished artist and sculptor Sir Eduardo Paolozzi. Another piece looks at a print by Jin Wicked in a similar way.

Turing Sources:

Guide to archives and photographs

Complete bibliography

Original documents

Alan Turing Archives and Photographs

Notes by Andrew Hodges,
author of
Alan Turing: the Enigma

The Modern Archives Centre,
King's College, Cambridge

The Turing Archive

The Turing Archive, the most important collection of Alan Turing's papers, is held in the Modern Archives Centre at King's College, Cambridge.

The King's College archivists have prepared a summary of the Turing Archive.

Much of the cataloguing work was done in the 1970s by the Contemporary Scientific Archives Centre which also offers much archival information on other British scientists.

Jonathan Swinton,
then a Fellow of King's College,
shows the new Digital Archive
to guests of the
Turing/Keynes event, 24 June 2000.

The Turing Digital Archive

Much of this collection of papers has been scanned or photographed to a high quality by the Intelligence Agents Multimedia department at Southampton University.

Since June 2000 the material has available on-line as the Turing Digital Archive.

This material is presented in an archival format without much editorial comment, although there is a search engine.

The Turing Bibliography gives pointers to all the scientific papers.

Jonathan Swinton's guide to the morphogenesis manuscripts should be used.

He is a leading scholar of Turing's
morphogenesis manuscripts
in the Archive,
one of its most important aspects.

Proceed to the Turing Digital Archive:

• Introduction page

• Main catalogue

There is another small collection in the National Archive for the History of Computing at Manchester. There are two files of Turing's programming for morphogenesis which are shown as being amongst the treasures of the archive.

The catalogue of the Turing collection may be seen.