Alan Turing

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Alan Turing (ca.1938)
His signature

Alan Mathison Turing OBE , FRS [ ˈælən ˈmæθɪsən ˈtjʊəɹɪŋ ] (born  June 23, 1912 in London , † June 7, 1954 in Wilmslow , Cheshire ) was a British logician , mathematician , cryptanalyst and computer scientist . Today he is considered one of the most influential theorists of early computer development and computer science . Turing created a large part of the theoretical basis for modern information and computer technology . His contributions to theoretical biology also proved to be trend-setting .

The predictability model of the Turing machine that he developed forms one of the foundations of theoretical computer science . During the Second World War he was instrumental in deciphering the German radio messages encrypted with the " Enigma ". Most of his work remained under lock and key even after the end of the war.

In 1953, Turing developed one of the first chess programs , whose calculations he made himself due to the lack of hardware . The Turing Award , the most important award in computer science, and the Turing test for checking the presence of artificial intelligence are named after him .

In March 1952, Turing was sentenced to chemical castration because of his homosexuality , which was still a criminal offense at the time . Turing fell ill with depression as a result of hormone treatment and died of suicide about two years later . In 2009, then British Prime Minister Gordon Brown made an official apology on behalf of the government for the “appalling treatment” of Turing and praised his “exceptional service” during the war; a pardon was rejected in 2011 despite a petition . On Christmas Eve, December 24, 2013, Queen Elizabeth II posthumously pronounced a “ Royal Pardon ” (royal pardon).

Live and act

Childhood and youth

Turing as a 16-year-old

Alan Turing's father, Julius Mathison Turing, was a British civil servant with the Indian Civil Service . He and his wife, Ethel Sara (nee Stoney) wanted their children to grow up in the UK. Therefore, before Alan's birth, the family returned from Chatrapur , then British India , to London-Paddington , where Alan Turing was born on June 23, 1912. Since his father's civil service was not yet over, he traveled again to India in the spring of 1913, where his wife followed him in the autumn. Turing and his older brother John were taken to St. Leonards-on-the-Sea, Hastings , to the family of a retired colonel and his wife into foster care. In the following period, the parents commuted between England and India until Turing's mother decided in 1916 to stay in England for a longer period and took the sons back to her home.

Turing's great talent and intelligence was already evident in early childhood. It is reported that he taught himself to read within three weeks and became attracted to numbers and puzzles from an early age.

At the age of six, Turing was sent to the private day school St. Michael's in St. Leonards-on-the-Sea, where the headmistress noticed his talent early on. In 1926, at the age of 14, he moved to the Sherborne School in Dorset . His first day of school there fell on a general strike in England. However, Turing was so motivated that he cycled the 100 kilometers from Southampton to school on his own, stopping at a pub only once a night; At least that's what the local press reported.

Turing's urge to study science met with little approval from his teachers in Sherborne; they bet more on the humanities than on the natural sciences. Even so, Turing continued to show remarkable skills in areas he loved. So he solved advanced problems for his age without having previously acquired any knowledge of elementary calculus .

In 1928 Turing came across the work of Albert Einstein . Not only did he understand it, but he took Einstein's law of motion independently from a text , although it was not explicitly mentioned.

College time and theoretical work

Turing's reluctance to work as hard for the humanities as he did for science resulted in his failing exams a few times. Because this worsened his grade point average, he had to go to a second choice college in 1931, King's College , Cambridge , contrary to his wish to study at Trinity College . He studied from 1931 to 1934 under Godfrey Harold Hardy (1877-1947), a respected mathematician who held the Sadleirian Chair at Cambridge, which was a center of mathematical research at the time.

1-band Turing machine : abstract model of a computer that can solve all calculable problems with just three operations ( read , write and move head )

In his work, On Computable Numbers, with an Application to the “ Decision Problem (May 28, 1936), which was fundamental to this branch of mathematics , Turing reformulated Kurt Gödel's 1931 results . He replaced Gödel's universal, arithmetic-based formal language with a simple thought mechanism, a mathematical machine that processes abstract-formal character strings and is known today as the Turing machine . ("Decision problem" refers to one of the 23 most important open problems in mathematics of the 20th century, presented by David Hilbert in 1900 at the 2nd International Congress of Mathematicians in Paris [" Hilbert's problems "].) Turing proved that such a device can be used in is able to "solve every conceivable mathematical problem, provided that it can also be solved by an algorithm ".

Turing machines are still one of the main focuses of theoretical computer science , namely the theory of computability. With the help of the Turing machine, Turing succeeded in proving that there is no solution to the decision problem. He showed that mathematics is in a certain sense incomplete because there is generally no way of determining whether any syntactically correct mathematical statement is provable or refutable. In addition, he proved that the holding problem for Turing machines cannot be solved. This means that it is not possible to algorithmically decide whether a Turing machine, applied to an input (initial tape occupancy), will ever come to a standstill, i.e. the calculation will terminate. Turing's proof was published only after the proof given by Alonzo Church (1903–1995) with the help of the lambda calculus ; independently of this, Turing's work is considerably simpler and more intuitively accessible. The term “universal (Turing) machine” was also new, a machine that can simulate any other Turing machine. So the input for this machine is an encrypted program that is interpreted by the universal machine and the starting value to which it is to be applied.

All of the predictability terms defined to date have proven to be equivalent (apart from the mapping of words to numbers and vice versa).

Turing spent most of 1938 and 1939 at Princeton University , where he studied under Alonzo Church. In 1938 he earned his doctorate from Princeton. His doctoral thesis introduced the term “ hypercomputation ”, in which Turing machines are expanded into so-called oracle machines. This made it possible to study non-deterministically solvable problems.

Career and research

After his return to Cambridge in 1939, Turing attended lectures by the Austro-British philosopher Ludwig Wittgenstein (1889–1951) on the fundamentals of mathematics. The lectures were reconstructed word for word from the students' notes, including heckling from Turing and other students. The two discussed and argued vehemently: Turing defended the mathematical formalism , while Wittgenstein was of the opinion that mathematics was overrated and could not bring absolute truth to light.


Replica of a Turing bomb

During the Second World War , Turing was one of the outstanding scientists in the successful attempts at Bletchley Park to decipher encrypted German radio messages. He contributed several mathematical models to both the Enigma (also see: Letchworth Enigma ) and the Lorenz cipher (see also: Turingery ) to break . The insights that Turing gained from the cryptanalysis of the Fish encryption later helped in the development of the first digital, programmable electronic tube computer ENIAC . Designed by Max Newman and his team and built in the Post Office Research Station in Dollis Hill by a team led by Tommy Flowers in 1943, Colossus deciphered the Lorenz machine . Turing also designed the bombs named after him . They were the successors of the Bomba developed by the Pole Marian Rejewski and were used to identify the keys to Enigma messages . This was an electromechanical device that basically contained several Enigma machines and was thus able to test and eliminate many possible key settings of the Enigma messages until a possible solution was found ( Reductio ad absurdum ; German return to to contradiction ).  

Turing's involvement as one of the most important code breakers in the deciphering of the Enigma was secret until the 1970s; not even his closest friends knew about it. The deciphering of secret German radio messages was a decisive factor in the victory of the Allies in the submarine war and in the African campaign .

Working on Early Computers - The Turing Test

Punch cards for the Automatic Computing Engine of the National Physical Laboratory in 1950

From 1945 to 1948 Turing worked at the National Physical Laboratory in Teddington, where he worked on the design of the ACE ( Automatic Computing Engine ). The name of the machine is derived from the analytical engine of the mathematician Charles Babbage , whose work Turing admired all his life.

From 1948 Turing taught at the University of Manchester and in 1949 became assistant director of the computer department. Here he worked on the software for one of the first real computers, the Manchester Mark I, and at the same time continued various theoretical work. In Computing machinery and intelligence ( Mind , October 1950), Turing took up the problem of artificial intelligence and suggested the Turing test as a criterion for whether a machine is capable of thinking in a comparable way to humans. Since the thinking process cannot be formalized, the test only considers the answers of a machine in dialogue with a human, i.e. H. the communicative behavior of the machine. If this does not appear to be distinguishable from human behavior, then we should speak of machine intelligence. With the publication, he significantly influenced the development of artificial intelligence.

In 1952 he wrote the Turochamp chess program . Since there were no computers with sufficient power to execute it, Turing took over its function and calculated every move himself. This took up to 30 minutes per move. He lost the only game documented in writing to a colleague.

Work on mathematical problems in biology

From 1952 until his death in 1954, Turing worked on mathematical problems in theoretical biology. In 1952 he published a paper on The Chemical Basis of Morphogenesis . This article was the first to describe a mechanism by which reaction-diffusion systems can spontaneously develop structures. This process, known as the Turing mechanism, is still the focus of many chemical-biological structure formation theories . Turing was also interested in the occurrence of Fibonacci numbers in the structure of plants. Later works remained unpublished until the publication of his collected works in 1992.

Persecution for homosexuality and Turing's death

At Berlin's Christopher Street Day 2012, which took place on Turing's 100th birthday, the British embassy advertised Turing as a code breaker. The state persecution had started sixty years earlier.

In 1952, 19-year-old Arnold Murray, with whom Turing had a same-sex relationship, helped an accomplice break into Turing's house. Turing then reported a theft to the police, who accused him of a sexual relationship with Murray as a result of the investigation. Since homosexual acts were criminal in England at the time - as in most other countries - Turing was charged with "gross fornication and sexual perversion". Turing saw no reason to justify these allegations.

After he was sentenced to prison, he was given the choice of serving the prison term or - since homosexuality was viewed as an illness by large parts of psychiatry in his day - to seek treatment. He opted for medical treatment, which also included drug treatment with the hormone estrogen . An instinctual effect was ascribed to this. The treatment lasted for a year and resulted in side effects such as enlargement of the mammary gland . Even if he commented on his physical changes with humor, the feminization of his contours must have hit the athletic runner and tennis player hard. Turing fell ill with depression . In the fall of 1952, Turing began his therapy with the psychoanalyst Franz Greenbaum , who came from Berlin and had lived in Manchester since 1939 . He was a fan of CG Jung and had been recommended by friends as understanding for his case. Turing also developed a friendly relationship with the Greenbaum family, whom he also visited privately.

In 1954 Turing died, probably according to the official statement by suicide , of cyanide poisoning , apparently resulting from a poisoned apple that was found half-eaten next to him. However, the investigators failed to have the apple examined for poison. It is reported that since 1938, after seeing the film “ Snow White and the Seven Dwarfs ”, Turing kept repeating the verses Dip the apple in the brew / Let the sleeping death seep through (“ Dip the apple deep into it / until the Poison will be in him ”, in the German version of the film:“ Apple turns bright red / lures Snow White to death ”) sang. The thesis that Turing's death was an accident in connection with a chemical test is strongly contradicted by Andrew Hodges, one of his biographers. It is widely believed among his biographers that the effects of hormone treatment were the main cause of the suicide.

Official apology, acknowledgment and rehabilitation

From around the late 2000s, British citizens undertook a number of high- profile activities to publicize the injustice suffered by Turing and to achieve his formal rehabilitation , i.e. a revocation or overturning of the judgment at the time. This led to success in 2013.

In 2009, around 30,000 Brits signed an online petition filed with the government demanding a posthumous apology from the UK government. The initiator of the campaign, the British programmer John Graham-Cumming, suggested that Alan Turing be given a knighthood . On September 10, 2009, then British Prime Minister Gordon Brown issued a statement in which he regretted the persecution of Turing on behalf of the British government and paid tribute to his extraordinary contribution during the Second World War . He also alluded to the strategic advantage of the Allies by deciphering the "Enigma" and underlined its importance:

“It is not an exaggeration to say that without his outstanding contribution the history of World War II could have been very different. Indeed, he is one of the few notable people whose unique contribution helped turn the course of the war. The deep gratitude we owe him therefore makes it all the more horrific that he was treated so inhumanely. 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 are sorry, you deserve so much better. "

- Gordon Brown , British Prime Minister at the time, 2009

Since the prosecution of his sexual orientation was in accordance with the law at the time, a subsequent lifting of the conviction of Turing was initially presented by the official side as impossible. As recently as 2012, the government of Brown's successor, David Cameron , refused to posthumously rehabilitate 49,000 homosexuals convicted under the Criminal Law Amendment Act of 1885.

In 2013 it was announced that the British government had plans to rehabilitate Turing after all . The Upper House member John Sharkey, Sharkey Baron requested this. The conservative member of the House of Lords Tariq Ahmad, Baron Ahmad of Wimbledon , announced the government's approval. The Liberal Democrat Sharkey had studied mathematics in Manchester in the 1960s with Turing's only graduate student Robin Gandy . The government scheduled a third reading of the motion for the end of October.

On December 24, 2013, Alan Turing was pardoned by a special right of grace, the so-called Royal Pardon , which was granted to the monarch alone . Justice Minister Chris Grayling had requested this pardon from Elizabeth II . Turing is thus also officially rehabilitated.

In April 2016, Robert Hannigan, the then head of the British secret service GCHQ , apologized for his institution's treatment of homosexuals, referring specifically to Alan Turing.

Aftermath of rehabilitation

At the beginning of 2015, members of the Alan Turings family, with further, sometimes prominent support ( Stephen Fry , Turing actor Benedict Cumberbatch ), petitioned the British Parliament for the rehabilitation of all other people convicted under homosexual laws in England. The petition was signed by approximately 500,000 people and was to be presented by Turing's great-nephew Nevil Hunt and great-niece Rachel Barns.

On October 21, 2016, the British Parliament rejected a bill that provided for rehabilitation in the form of a general rehabilitation of all living persons previously convicted of homosexuality. This bill went too far for some and not enough for others. On January 31, 2017, Queen Elizabeth II enacted a law that, based on Turing's pardon, waives the sentence for all men if both were over 16 years old at the time when they performed the punished act by mutual consent . Convictions for homosexual acts in public toilets are also excluded. The law also includes people who have already died. A survivor who is still alive can request that the sentence be removed from their police record, and historians can suggest that a conviction of deceased persons is invalid under applicable law. The law, referred to as "Turing's Law" by Attorney General Sam Gyimah , is a supplement to the Policing and Crime Act and makes no reference to any other law that could prosecute homosexual acts. By Michael Cashman , one of the initiators of the law, but further agreements have been secured to enable a suitably comprehensive amnesty for all homosexual acts.

Posthumous honors

Statue of Turing at the University of Surrey

On 23 June 1998, the Turing's 86th birthday would have been, was a blue plaque ( English Heritage Blue Plaque ) to his birthplace in Warrington Crescent, London, revealed.

On March 2, 1999, the asteroid (10204) Turing was named after him.

A Turing statue was unveiled in Manchester on June 23, 2001. It is in Sackville Park , between the science buildings of Manchester University and the gay area of Canal Street .

On the 50th anniversary of his death, June 7, 2004, a plaque was unveiled at his former home, Hollymeade, in Wilmslow, to commemorate Turing's untimely death.

The Turing Award is presented annually by the Association for Computing Machinery to people who have made significant contributions to computer science. It is widely regarded as the " Nobel Prize " in computer science.

The Bletchley Park Trust unveiled a statue of Turing in Bletchley Park on June 19, 2007 . The sculpture was designed by Stephen Kettle , who used Welsh slate as the material for his artwork .

In the “Turing Year 2012”, Alan Turing's hundredth birthday was celebrated by events around the world to honor and commemorate his achievements.

In 2014 he was inducted into the Hall of Honor of the US National Security Agency ( NSA ).


Plaque on Turing's house
  • Alan Turing was an excellent long-distance runner . From 1946 he started competing for the Walton Athletic Club. At the English marathon championships in 1947 he was fifth in 2:46:03 h, only a good five minutes slower than the time with which Stan Jones was the third British man behind in the Polytechnic Marathon of the following year (in which Turing was injured) Jack Holden and Tom Richards qualified for the 1948 London Olympic Games marathon . In 1950 Turing had to end his sports career because of a leg injury.
  • Allegedly, Apple took inspiration from the death of the computer pioneer Turing when designing its logo, a bitten apple (originally in rainbow colors). However, this assumption was refuted by Steve Jobs by saying that he wished he had thought of it then, but he didn't. Apple had the legend in mind that Isaac Newton was said to have been inspired to his theory of gravity when an apple fell on his head. The logo designer Rob Janoff said that the bite was only added as a size measure, for example to avoid confusion with a cherry.
  • In his memoirs, the computer pioneer Heinz Billing from the Max Planck Institute for Physics (Munich) reports that Alan Turing and Konrad Zuse met in Göttingen in 1947. In the form of a colloquium, British experts (in addition to Turing and others John R. Womersley and Arthur Porter ) interviewed German scientists such as Zuse, Billing, Alwin Walther and Helmut Schreyer .
  • In 2012, a year-long cycle of exhibitions was shown in the Heinz Nixdorf MuseumsForum in Paderborn in honor of Turing under the title Genial & Secret .
  • Reports from acquaintances about him are sometimes bizarre: he always chained his teacup to his heater with a bicycle lock and rode a bicycle with a misappropriated gas mask to protect himself against his hay fever while cycling. Residents of the small town Bletchley were shocked and believed the sight of a German poison gas attack.
  • At the Institute for Computer Science at the Westphalian Wilhelms University in Münster , two original prints of Turing's most important publications were discovered in the estate of Heinrich Scholz by Achim Clausing towards the end of the first decade of the 2000s , one of which had been lost since 1945. It is the work On Computable Numbers, with an Application to the “Decision Problem” from 1936, which Scholz had asked for in the same year with a postcard from Turing. On the basis of this work, according to Clausing's statement, Scholz held “the world's first seminar on computer science”. The second work dates from 1950 and is a treatise on the development of artificial intelligence, which Turing provided with a handwritten comment: “This is probably my last copy”. At Sotheby’s , comparable prints by Turing that did not have a dedication were auctioned for 180,000 euros .
  • In 2017, a previously unknown collection of 147 letters from Turing was discovered. Another collection of 141 letters was also found that year in a filing cabinet in a storage room at Manchester University. The letters date from 1949 to 1954. The letters discovered at the University of Manchester mainly deal with his research work and have been taken over by the university's archives; they can be viewed on the Internet.
  • In July 2019, the Bank of England announced that on the new £ 50 note that will be in circulation from the end of 2021 the picture of Turing and his quote “This is only a foretaste of what is to come, and only the shadow of what is going to be. ”will be on display.



Important publications

English editions

  • Darrel C. Ince (Ed.): Mechanical intelligence (=  Collected Works of AM Turing . Band 1 ). North Holland, Amsterdam 1992, ISBN 978-0-444-88058-1 .
  • JL Britton (Ed.): Pure Mathematics (=  Collected Works of AM Turing . Volume 2 ). North Holland, Amsterdam 1992, ISBN 978-0-444-88059-8 .
  • PT Saunders (Ed.): Morphogenesis (=  Collected Works of AM Turing . Band 3 ). North Holland, Amsterdam 1992, ISBN 978-0-444-88486-2 .
  • Robin O. Gandy, CEM Yates (Ed.): Mathematical Logic (=  Collected Works of AM Turing . Volume 4 ). North Holland, Amsterdam 2001, ISBN 978-0-444-50423-4 .
  • Jack Copeland (Ed.): The Essential Turing . Seminal Writings in Computing, Logic, Philosophy, Artificial Intelligence, and Artificial Life plus The Secrets of Enigma. Oxford University Press, Oxford 2004, ISBN 0-19-825080-0 .
  • S. Barry Cooper, Jan van Leeuwen (Eds.): Alan Turing: His Work and Impact . Elsevier, New York 2013, ISBN 978-0-12-386980-7 (contains almost all of the Collected Works , with extensive commentary, but without concordance).

German edition and translations

  • Alan M. Turing: Can a machine think? In: Hans Magnus Enzensberger (Hrsg.): Neue Mathematik (=  course book . Volume 8 ). Suhrkamp, ​​Frankfurt am Main 1967 (original title: Computing Machinery and Intelligence . 1950. Translated by P. Gänßler).
  • Friedrich Kittler , Bernhard Dotzler (Ed.): Intelligence Service. Fonts . Brinkmann et al. Bose, Berlin 1987, ISBN 3-922660-22-3 (Contains informative introduction. Extensive selection).
  • Alan M. Turing: Can a machine think? In: Walther Ch. Zimmerli, Stefan Wolf (Ed.): Artificial Intelligence. Philosophical problems . Reclam, Stuttgart 1994, ISBN 3-15-008922-0 (Original title: Computing Machinery and Intelligence . 1950. Translated by P. Gänßler).


Literature (selection)

Theory and discussion

History and biography

  • Andrew Hodges : Alan Turing - The Enigma. Burnett Books, London, and Simon and Schuster, New York 1983, Vintage, New York 1992, (biography).
    • Alan Turing - Enigma . Translation by Rolf Herken and Eva Lack. Kammerer and Unverzagt, Berlin 1989, 662 pages, ISBN 3-9801050-5-9 . 2nd edition Springer 1994, ISBN 3-211-82627-0 .
  • David Leavitt: The Man Who Knew Too Much. Alan Turing and the Invention of the Computer. WW Norton & Co, 2006, ISBN 0-393-32909-7 .


Films (selection)



  • Robert Deutsch: Turing . Avant 2017. ISBN 978-3-945034-55-2 .
  • David Etien: Champignac: Enigma . Editions Dupuis January 4th 2019.

Web links

Commons : Alan Turing  - collection of pictures, videos and audio files


Individual evidence

  1. ^ Andrew Hodges : The Alan Turing Internet Scrapbook. In: , (English), accessed on August 19, 2017.
  2. ^ Alan Turing: Colleagues share their memories. In: BBC News , June 23, 2012.
  3. ^ Alphabetical list of members of the Royal Society (PDF; 1.1 MB), accessed on July 18, 2012.
  4. ^ Andrew Hodges: Alan Turing - a short biography. In: , 1995.
  5. ^ Alan Turing: Manchester celebrates pardoned genius. In: BBC News , December 24, 2013, accessed December 25, 2013.
  6. Andrew Hodges: Alan Turing, Enigma . Kammerer & Unverzagt, Berlin 1989, ISBN 3-9801050-5-9 , p. 526 ff., in particular p. 545 .
  7. Caroline Davies: Enigma Codebreaker Alan Turing receives Royal Pardon. In: The Guardian , December 24, 2013.
  8. ^ Friedhelm Greis: Homosexuality. Queen pardons Alan Turing. In: , December 27, 2013.
  9. ^ Royal pardon for codebreaker Alan Turing. In: BBC News , December 24, 2013, accessed December 25, 2013.
  10. see also list Recipients of British royal pardons and article Royal prerogative of mercy in the English language Wikipedia
  11. ^ A b G. James Jones: Alan Turing - Towards a Digital Mind: Part 1 . In: System Toolbox . December 11, 2001. Archived from the original on August 3, 2007. Retrieved July 27, 2007.
  12. Andrew Hodges: Alan Turing: the enigma . Burnett Books, London 1983, ISBN 978-0-09-152130-1 .
  13. ^ Cora Diamond (ed.): Wittgenstein's Lectures on the Foundations of Mathematics , University of Chicago Press, 1976
  14. Andrew Hodges: Alan Turing: The Enigma . Princeton University Press, 2014, ISBN 978-0-691-16472-4 , pp. 193-195 .
  15. He cracked the secret code. He wanted nothing but quiet. But they didn't let him. In the end he was disciplined by the British, whose survival he had ensured. A homage to Alan Turing, the decipherer of the Nazi enigma and inventor of the computer. In: Das Magazin , No. 6, 2012, special issue on digital happiness .
  16. André Schulz: The golden goose that never chatters. In: Schach Nachrichten , June 7, 2004, about Turing and chess.
  17. Boris Mayer: No code was too difficult for him. In: Jungle World , June 28, 2012, No. 26; Retrieved August 19, 2017.
  18. a b What was Alan Turing really like? In: BBC News , June 5, 2014; Retrieved June 7, 2014.
  19. to seep through sth. In: , Collins dictionary online, see below, under the examples, accessed February 18, 2015.
  20. a b Jack Schofield: No 10 apologises for “appalling” treatment of Alan Turing . In: The Guardian , September 11, 2009. Original quote: “It is no exaggeration to say that, without his outstanding contribution, the history of World War Two could well have been very different. He truly was one of those individuals we can point to whose unique contribution helped to turn the tide of war. The debt of gratitude he is owed makes it all the more horrifying, therefore, that he was treated so inhumanely. 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. "
  21. ^ Thousands call for Turing apology. In: BBC News , August 31, 2009.
  22. ^ Felix Knoke: Netzweltticker. British apologize to computer pioneer Turing. In: SpOn , September 1, 2009.
  23. a b Werner Pluta: Alan Turing. Late rehabilitation for the computer pioneer. In: , July 23, 2013, accessed on July 23, 2013.
  24. Nicholas Watt: Enigma codebreaker. Alan Turing to be given posthumous pardon. In: The Guardian , July 19, 2013, accessed July 23, 2013.
  25. ^ Royal pardon for codebreaker Alan Turing. In: BBC News , December 24, 2013; Retrieved March 23, 2013.
  26. ^ Press Association: GCHQ chief apologises for 'horrifying' treatment of Alan Turing. In: The Guardian. April 16, 2016, accessed on April 16, 2016 (English): " I am happy to do so today and to say how sorry I am that he and so many others were treated in this way, right up until the 1990s, when the policy was rightly changed. The fact that it was common practice for decades reflected the intolerance of the times and the pressures of the cold war, but it does not make it any less wrong and we should apologize for it. Their suffering was our loss and it was the nation's loss too because we cannot know what Ian and others who were dismissed would have gone on to do and achieve. We did not learn our lesson from Turing. "
  27. ^ Catholic News Agency (KNA) / dpa : Gays should be rehabilitated. In: Badische Zeitung , February 24, 2015.
  28. ^ 'Turing Bill' for gay pardons fails in Parliament. In: BBC. October 21, 2016, accessed October 21, 2016 .
  29. Owen Bowcott: UK issues posthumous pardons for Thousands of gay men. In: The Guardian , January 31, 2017; accessed February 1, 2017.
  30. London Blue Plaques . In: English Heritage . Archived from the original on September 3, 2009. Retrieved February 10, 2007.
  31. Photos: The Turing statue in Bletchley Park . In: , August 31, 2011.
  32. ^ Turing year 2012. In: Gesellschaft für Informatik , 2012, accessed on August 19, 2017.
  33. Chris Christensen: Review of the IEEE Milestone Award to the Polish Cipher Bureau for “The First Breaking of Enigma Code”. In: Cryptologia , April 15, 2015, p. 192, doi: 10.1080 / 01611194.2015.1009751 , payable.
  34. ^ IEG Green: In isolation and autonomy: the marathon ambition of a computer genius, Alan Turing. In: Track Stats , September 2009, (English).
  35. Pat Butcher: In Praise of Great Men. In: September 14, 2009, (English).
  36. ^ John Graham-Cumming: An Olympic honor for Alan Turing. In: The Guardian , March 10, 2010, (English).
  37. He [Steve Jobs] replied that he wished he had thought of that, but hadn't. In: Walter Isaacson : Steve Jobs . 2011.
  38. ^ Greg Gore: Understanding the Enigma of the Apple Computer Logo. In: February 12, 2003, accessed September 13, 2010 .
  39. Holden Frith: Unraveling the tale behind the Apple logo. In: CNN , October 7, 2011, (English).
  40. Heinz Billing: A life between research and practice. Self-published by F. Genscher, Düsseldorf 1997, p. 156; reproduced from Herbert Bruderer: Konrad Zuse and Switzerland: Who invented the computer? Oldenbourg Wissenschaftsverlag, Munich 2012, ISBN 978-3-486-71665-8 , p. 64, (online).
  41. Hans-Heinrich Pardey: Ingenious and quirky. In: Frankfurter Allgemeine Sonntagszeitung , January 15, 2012, beginning of the article .
  42. Laura Döing: The secret acts of Alan Turing. In: Deutsche Welle , January 29, 2012.
  43. Karin Völker: Turing's documents in the university basement. (PDF; 1,087 kB) In: Westfälische Nachrichten . Westfälische Wilhelms-Universität, January 25, 2015, accessed on August 19, 2017 .
  44. a b c d e Elmar Ries: In the footsteps of a pioneer: The Münster University Library has offprints by the computer scientist Alan Turing. In: Westfälische Nachrichten , January 28, 2013, accessed on December 9, 2013.
  45. ^ AM Turing ( digitized version ): Computing machinery and intelligence. In: Westphalian Wilhelms University. Digital collection of the University of Münster, accessed on August 19, 2017 .
  46. Josh Halliday: Collection of letters by codebreaker Alan Turing found in filing cabinet. In: The Guardian, August 27, 2017, accessed August 27, 2017
  47. ^ Alan Turing Papers (Additional) in the archives of the University of Manchester
  48. Computer pioneer Turing on a new £ 50 note., July 15, 2019, accessed on July 17, 2019 .
  49. Breaking the Code / The coded man in the Internet Movie Database (English)
  50. Codebreaker / The Code Breaker. Alan Turing in the Internet Movie Database (English)
  51. ^ Concert: A Man From The Future. In: Pet Shop Boys , April 24, 2014.
  52. Teresa Dapp: Musical bow to Alan Turing. In: dpa / Mittelbayerische Zeitung , July 24, 2014.