The Life and Story of Alan Turing

Written by Shambhavi Mathur, Aryan Sethi, and Zoya Khan

“A computer would deserve to be called intelligent if it could deceive a human into believing that it was human.”

Early Life

Alan Mathison Turing was born in Maida Vale, London on 23 June 1912. His father, Julius Mathison Turing, was a British member of the Indian Civil Service, and he frequently visited other countries. Alan 's mother, Ethel Sara Stoney, was the daughter of the Madras railway chief engineer, and Alan 's parents had met in India and married. When Alan was about one year old his mother rejoined her husband in India, leaving Alan with family friends in England. Alan was sent to school but after a few months, he did not seem to get any benefit so he was removed from the school.

Turing Was an English mathematician computer scientist, logician, cryptanalyst, philosopher, and theoretical biologistTuring was highly influential in the development of theoretical computer science, providing a formalization of the concepts of algorithm and computation with the Turing machine, which can be considered a model of a general-purpose computer. Turing is widely considered to be the father of theoretical computer science and artificial intelligence.

Turing in school:

His intelligence was clear from his school days. At the age of 9, his headmistress from St Michael's Primary School in Hastings reported: ‘I have had clever boys and hard-working boys, but Alan is a genius’. In 1922, Turing moved to Hazelhurst Preparatory School where he became interested in chess, spending hours on his own working out complex chess problems.

He attended Sherborne School at Dorset, at the age of 13. Although his math teacher Mr. Randolph declared him a ‘genius’, this had little to do with a school that put its emphasis on humanities and classics. Often teachers would get annoyed with him for his high marks in examinations despite having paid little attention during lessons.

Turing formed a significant friendship at Sherborne with fellow pupil Christopher Collan Morcom (July 13, 1911 – February 13, 1930), described as the "first love" of Turing. Their relationship gave inspiration to Turing's future endeavors, but it was cut short by the death of Morcom from complications of bovine tuberculosis in February 1930. The event triggered a great sorrow for Turing. He coped with his grief by working so much harder on the science and mathematics subjects that he had shared with Morcom.

Turing 's relationship with Morcom 's mother continued with her sending gifts to Turing long after Morcom 's death, and with him sending letters, typically on the birthdays of Morcom. Some have speculated that the death of Morcom was the reason for Turing's atheism and materialism. He apparently still believed in such concepts as a spirit, independent of the body, and surviving death at this point in his life.

University years:

After Sherborne, Turing studied mathematics at King's College, Cambridge as an undergraduate from 1931 to 1934. He settled in much better in this academic environment and his years in his work as well as in social life were highly successful. Turing took up rowing and became an excellent runner on the long distance. He also joined the Anti-War Council, which called for the peace movement, which called for chemicals and munitions workers to strike if the war was declared amid the rise of Hitler.

In 1936, Turing published his paper "On computable numbers, with an application to the Entscheidungsproblem.” It was published in the Proceedings of the London Mathematical Society journal in two parts, the first on 30 November and the second on 23 December. In this paper, Turing reformulated Kurt Gödel’s 1931 results on the limits of proof and computation, replacing Gödel's universal arithmetic-based formal language with the formal and simple hypothetical devices that became known as Turing machines.

In 1936 Turing went on to study mathematics at Princeton University, New Jersey, and in 1938 received his Ph.D. He developed the concept of a 'universal computing machine' during his time here, which could solve complex calculations. This would become known as the Turing machine, foreshadowing the digital machine.

He also studied cryptology, the study of codes and ciphers, which can be used to send secret messages, and he built an electro-mechanical binary multiplier three out of four stages.

Facts about Alan Turing:

o Turing’s first day of Sherborne School coincided with the 1926 General Strike but he was so determined to make it in that he cycled 60 miles.

o Turing was often spotted running along the riverside paths between Cambridge and Ely; this is commemorated by an annual race, the Turing Relay that takes place along those tracks.

o Alan Turing is credited with designing the first computer chess program in 1950, named Turochamp.

o Turing was known for his eccentricity at Bletchley Park. His colleagues called him 'Prof' and his treatise on the Enigma was known as 'The Prof's Book'.

Awards and recognition:

Turing has been honored in various ways in Manchester, the city where he worked towards the end of his life. In 1994, a stretch of the A6010 road (the Manchester city intermediate ring road) was named "Alan Turing Way". A bridge carrying this road was widened and carries the name Alan Turing Bridge. A statue of Turing was unveiled in Manchester on 23 June 2001 in Sackville Park between the University of Manchester building on Whitworth Street and Canal Street. The memorial statue depicts the "father of computer science" sitting on a bench at a central position in the park. Turing is shown holding an apple. The cast bronze bench carries in relief the text 'Alan Mathison Turing 1912–1954', and the motto 'Founder of Computer Science'.


The Entscheidungsproblem

In Turing’s time, rote-workers were in fact called “computers,” and human computers carried out some aspects of the work later done by electronic computers. The Entscheidungsproblem sought an effective method for solving the fundamental mathematical problem of determining exactly which mathematical statements are provable within a given formal mathematical system and which are not. A method for determining this is called a decision method. In 1936 Turing and Church independently showed that, in general, the Entscheidungsproblem problem has no resolution, proving that no consistent formal system of arithmetic has an effective decision method. In fact, Turing and Church showed that even some purely logical systems, considerably weaker than arithmetic, have no effective decision method. This result and others—notably mathematician-logician Kurt Gödel’s incompleteness results—dashed the hopes, held by some mathematicians, of discovering a formal system that would reduce the whole of mathematics to methods that (human) computers could carry out. It was in the course of his work on the Entscheidungsproblem that Turing invented the universal Turing machine, an abstract computing machine that encapsulates the fundamental logical principles of the digital computer.

The Church-Turing thesis

An important step in Turing’s argument about the Entscheidungsproblem was the claim, now called the Church-Turing thesis, that everything humanly computable can also be computed by the universal Turing machine. The claim is important because it marks out the limits of human computation. Church in his work used instead of the thesis that all human-computable functions are identical to what he called lambda-definable functions (functions on the positive integers whose values can be calculated by a process of repeated substitution). Turing showed in 1936 that Church’s thesis was equivalent to his own, by proving that every lambda-definable function is computable by the universal Turing machine and vice versa. In a review of Turing’s work, Church acknowledged the superiority of Turing’s formulation of the thesis over his own (which made no reference to computing machinery), saying that the concept of computability by a Turing machine “has the advantage of making the identification with effectiveness…evident immediately.”

Cracking the Enigma Code

The Bombe machine, designed by British mathematician Alan Turing at Bletchley Park during the early stages of World War II, was crucial to cracking German communications encoded by the Enigma machine.

The machine was a precursor to what we think of computers now. It used to speed up the rate at which intercepted messages were decoded. This helped the Allied Forces (Great Britain, China, France, Soviet Union, and the United States) react to the decoded messages within hours rather than weeks.

Using intelligence provided by the Poles, Turing set about cracking the Enigma messages with his own computer. His methods were based around the assumption that each message contained a crib - a known piece of German plaintext at a familiar point in the message.

Once the Enigma machine was cracked, 211 Bombe machines were built and ran around the clock. They were stationed at different locations across Britain, in order to reduce the threat of bombings wiping out these highly complex and expensive pieces of kit.

It’s estimated that this knowledge played such important roles in key battles that the work of the Bombe and the team at Bletchley Park shortened the war by two years.

The story of Turing and the Bletchley Park ‘codebreakers,’ for years kept secret, has now become part of national folklore. Information about the work at Bletchley was declassified in the 1970s, while Robert Harris’s novel Enigma, 2014 movie The Imitation Game and the Andrew Hodge book that inspired it have also all shed light on the ground-breaking work.

Sir John Dermot Turing, the nephew of Alan Turing, commented: “Alan Turing wanted to work on the German Navy version of Enigma because it was one of the toughest problems they had at Bletchley Park. Success against the Enigma played a major role in the Battle of the Atlantic, as it enabled convoys to be re-routed around the wolf-packs of U-boats. It is tremendous to see one of these rare machines which is so closely linked to Alan Turing’s achievements here at the Institute which bears his name.”

The Turing Test

The Turing Test is a method of inquiry in artificial intelligence (AI) for determining whether or not a computer is capable of thinking like a human being. The test was introduced by Alan Turing in his 1950 paper, "Computing Machinery and Intelligence" while working at the University of Manchester.

Turing proposed that a computer can be said to possess if it can mimic human responses under specific conditions. The original Turing Test required 3 terminals, each of which is separated from the other two. One terminal was operated by a computer, while the other two by humans.

One of the humans functions as a questioner during the test while the other human and the computer as respondents. The questioner interrogates the respondents and then asked to decide which respondent was the computer and which was human. The same is repeated multiple times. Now if the questioner makes the correct determination in half of the test runs or less, the computer is considered to possess artificial intelligence.

Turing predicted that machines would eventually be able to pass the test; in fact, he estimated that by the year 2000, machines with around 100 MB of storage would be able to fool 30% of human judges in a five-minute test and that people would no longer consider the phrase "thinking machine" contradictory.

Personal life

Alan Turing was a genius with a posh personal life. In 1941, he proposed marriage to Hut 8 colleague Joan Clarke, a fellow mathematician and cryptanalyst, but their engagement was short-lived. After admitting his homosexuality to his fiancée, who was reportedly "unfazed" by the revelation, Turing decided that he couldn't undergo the wedding. In January 1952, he started a relationship with Arnold Murray, a 19-year-old unemployed man. Just before Christmas, Turing was walking along Manchester's Oxford Road when he met Murray and invited him to lunch. On 23 January, Turing's house was burgled. Murray told Turing that he and therefore the burglar were acquainted, and Turing reported the crime to the police. During the investigation, he acknowledged a relationship with Murray. Homosexual acts were criminal offenses within the UK at that point, and both men were charged with "gross indecency" under Section 11 of the legal code Amendment Act 1885. Initial committal proceedings for the trial were persisted 27 February during which Turing's solicitor "reserved his defense", i.e., didn't argue or provide evidence against the allegations.

On 8 June 1954, Turing's housekeeper found him dead at the age of 41; he had died the previous day. Poisoning was established because of the explanation for death. When his body was discovered, an apple lay half-eaten beside his bed, and although the apple wasn't tested for cyanide, it had been speculated that this was the means by which Turing had consumed a fatal dose. An inquest determined that he had committed suicide. Andrew Hodges and David Leavitt have both speculated that Turing was re-creating a scene from the Disney film Snow White and therefore the Seven Dwarfs, his favorite fairy tale. Both men noted that (in Leavitt's words) he took "an especially keen pleasure within the scene where the Wicked Queen immerses her apple within the poisonous brew". Turing's remains were cremated at Woking Crematorium on 12 June 1954, and his ashes were scattered within the gardens of the crematorium, even as his father's had been.

Philosophy professor Jack Copeland has questioned multiple aspects of the coroner's historical verdict. He suggested an alternate explanation for the explanation for Turing's death: the accidental inhalation of cyanide fumes from an apparatus wont to electroplate gold onto spoons. The cyanide was wont to dissolve the gold. Turing had such an apparatus found out in his tiny spare room. Copeland noted that the autopsy findings were more according to inhalation than with the ingestion of the poison. Turing also habitually ate an apple before getting to bed, and it had been commonplace for the apple to be discarded half-eaten. Additionally, Turing had reportedly borne his legal setbacks and hormone treatment (which had been discontinued a year previously) "with good humor" and had shown no sign of despondency before his death. He even set down an inventory of tasks that he intended to finish upon returning to his office after the vacation weekend. Turing's mother believed that his death was an accident, resulting from his careless storage of laboratory chemicals. Biographer Andrew Hodges theorized that Turing arranged the delivery of the equipment to deliberately allow his mother plausible deniability with reference to any suicide claims.

Conspiracy theorists acknowledged that Turing was the explanation for intense anxiety to British authorities at the time of his death. The key services feared that communists would entrap prominent homosexuals and use them to collect intelligence. Turing was still engaged in highly classified work when he was also a practicing homosexual who holidayed in European countries near the ideological barrier. Consistent with the conspiracy theory, it's possible that the key services considered him too great a security risk and assassinated one among the foremost brilliant minds in their employ.

It has been suggested that Turing's belief in fortune-telling may have caused his depressed mood. While he was young, he had been told by a fortune-teller that he would be a genius. Shortly before his death, during a day-trip to St Annes-on-Sea with the Greenbaum family, Turing again decided to consult a fortune-teller.

In August 2009, British programmer John Graham-Cumming started a petition urging the British government to apologize for Turing's prosecution as a homosexual. The petition received quite 30,000 signatures. The Prime Minister, Gordon Brown, acknowledged the petition, releasing a press release on 10 September 2009 apologizing and describing the treatment of Turing as "appalling". In December 2011, William Jones and his Member of Parliament, John Leech, created an e-petition requesting that British government pardon Turing for his conviction of "gross indecency". The petition gathered over 37,000 signatures and was submitted to Parliament by the Manchester MP John Leech but the request was discouraged by Justice Minister Lord McNally.

In September 2016, the government announced its intention to expand this retroactive exoneration to other men convicted of comparable historical indecency offenses, in what was described as an "Alan Turing law". The Turing law is now an off-the-cuff term for the law within the United Kingdom contained within the Policing and Crime Act 2017, which is an amnesty law to retroactively pardon men who were cautioned or convicted under historical legislation that outlawed homosexual acts. The law applies in England and Wales.


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