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Alan Turing: the story on HearLore | HearLore
Alan Turing
On the 1st of September 1926, a thirteen-year-old Alan Turing rode his bicycle unaccompanied from Southampton to Sherborne, a journey of nearly one hundred miles, to attend the first day of term at his new boarding school. This feat of endurance was not merely a display of physical stamina but a declaration of independence from the rigid expectations of his era. While other boys might have accepted the General Strike as a reason to stay home, Turing saw the disruption as a challenge to be met. He slept in an inn along the way, ate what he could find, and arrived at the school gates determined to prove his worth. His headmaster, however, was not impressed by his cycling prowess or his mathematical genius. The headmaster wrote to Turing's parents expressing a fear that Alan would fall between two stools, suggesting that if he was to be a scientific specialist, he was wasting his time at a public school that valued the classics. This early clash between institutional tradition and raw intellectual potential set the stage for a life that would constantly struggle against the boundaries of what society deemed acceptable for a man of his talents.
The Universal Machine
In the spring of 1936, Turing sent a thirty-six-page paper to the Proceedings of the London Mathematical Society that would fundamentally alter the course of human history. The paper, titled On Computable Numbers, introduced the concept of a universal computing machine, a hypothetical device capable of performing any conceivable mathematical computation if it were representable as an algorithm. This was not merely a theoretical exercise; it was the blueprint for the modern computer. Turing replaced the complex arithmetic-based formal language of Kurt Gödel with a simple, hypothetical device that read and wrote symbols on a strip of tape. He proved that there was no solution to the Entscheidungsproblem, the decision problem posed by David Hilbert, by showing that the halting problem for Turing machines was undecidable. This insight meant that there were problems that no computer, no matter how powerful, could ever solve. The Church-Turing thesis, which emerged from this work, established that Turing machines and lambda calculus were capable of computing anything that is computable. John von Neumann later acknowledged that the central concept of the modern computer was due to Turing's paper, cementing his status as the father of theoretical computer science.
The War In The Shadows
On the 4th of September 1939, the day after the United Kingdom declared war on Germany, Turing reported to Bletchley Park, the secret wartime station of the Government Code and Cypher School. He was required to sign the Official Secrets Act, agreeing not to disclose anything about his work, a restriction that would silence him for decades. Turing's primary task was to break the Enigma cipher used by Nazi Germany, a machine that generated an astronomical number of possible settings. He developed the bombe, an electromechanical machine that could find the correct settings for the Enigma machine much faster than human operators. By late 1941, the team at Bletchley Park was frustrated by the sheer volume of German naval communications. Turing and his colleagues wrote directly to Winston Churchill, emphasizing their limited resources compared to the vast expenditure of the forces. Churchill responded with a memo reading Action This Day, which ensured they received all the resources they needed. More than two hundred bombes were in operation by the end of the war. Official war historian Harry Hinsley estimated that this work shortened the war in Europe by more than two years, a contribution that saved countless lives and prevented the Axis powers from dominating the Atlantic. Despite his crucial role, Turing's work remained secret, and he was appointed an Officer of the Order of the British Empire in 1946, yet the details of his achievements were hidden from the public eye.
Common questions
When was Alan Turing born and when did he die?
Alan Turing was born in 1912 and died on the 8th of June 1954 at his house at 43 Adlington Road in Wilmslow. A post mortem determined he died at age forty-one with cyanide poisoning cited as the cause of death.
What did Alan Turing publish in 1936?
In the spring of 1936, Alan Turing sent a thirty-six-page paper titled On Computable Numbers to the Proceedings of the London Mathematical Society. This paper introduced the concept of a universal computing machine and proved that the halting problem for Turing machines was undecidable.
How did Alan Turing contribute to World War II?
Alan Turing reported to Bletchley Park on the 4th of September 1939 to break the Enigma cipher used by Nazi Germany. He developed the bombe machine and his work shortened the war in Europe by more than two years according to official war historian Harry Hinsley.
What happened to Alan Turing after his 1952 conviction?
After his conviction for gross indecency on the 23rd of January 1952, Alan Turing was given a choice between imprisonment and chemical castration. He accepted injections of stilboestrol which rendered him impotent and caused breast tissue to form.
When did the British government apologize to Alan Turing?
British Prime Minister Gordon Brown released a statement on the 10th of September 2009 apologizing for the prosecution of Alan Turing. Queen Elizabeth II signed a pardon for Turing's conviction on the 24th of December 2013 with immediate effect.
Turing was not just a man of numbers; he was a man of motion. At Bletchley Park, he was known to his colleagues as Prof, and his treatise on Enigma was known as the Prof's Book. He was a talented long-distance runner, capable of world-class marathon standards. He occasionally ran the twenty-six miles to London when he was needed for meetings, a feat that would have exhausted most men. Turing tried out for the 1948 British Olympic team, but he was hampered by an injury. His tryout time for the marathon was only eleven minutes slower than the British silver medallist Thomas Richards' Olympic race time of two hours and thirty-five minutes. He was Walton Athletic Club's best runner, a fact discovered when he passed the group while running alone. When asked why he ran so hard in training, he replied that he wanted to see how fast he could go. This physical discipline mirrored his mental discipline, as he approached problems with the same intensity and focus. His eccentricity was not just a quirk but a defining characteristic of his personality, one that made him both a brilliant asset and an outsider in the eyes of his peers.
The Chemical Basis Of Life
In 1951, at the age of thirty-nine, Turing turned his attention to mathematical biology, publishing his masterpiece The Chemical Basis of Morphogenesis in January 1952. He was interested in morphogenesis, the development of patterns and shapes in biological organisms. He suggested that a system of chemicals reacting with each other and diffusing across space, termed a reaction-diffusion system, could account for the main phenomena of morphogenesis. Turing used systems of partial differential equations to model catalytic chemical reactions. He discovered that patterns could be created if the chemical reaction not only produced a catalyst but also produced an inhibitor that slowed down the production of the catalyst. If the two chemicals diffused through the container at different rates, patterns such as spots and stripes could emerge. This work was ahead of its time, as the structure and role of DNA were not yet understood. Some of this work aimed to understand plant phyllotaxy, specifically how plant primordia form in a ring around the apical meristem during plant growth and development, forming Fibonacci series. A study conducted in 2023 confirmed Turing's mathematical model hypothesis, experimentally verifying his insights with living vegetation. His work remains relevant today, explaining the growth of feathers, hair follicles, the branching pattern of lungs, and even the left-right asymmetry that puts the heart on the left side of the chest.
The Conviction That Changed Everything
On the 23rd of January 1952, Turing's house in Wilmslow was burgled, and during the investigation, he acknowledged a sexual relationship with the burglar, Arnold Murray. Homosexual acts were criminal offences in the United Kingdom at that time, and both men were charged with gross indecency under Section 11 of the Criminal Law Amendment Act 1885. Turing was convicted and given a choice between imprisonment and probation. His probation was conditional on his agreement to undergo hormonal physical changes designed to reduce libido, known as chemical castration. He accepted the option of injections of what was then called stilboestrol, a synthetic oestrogen. This treatment rendered Turing impotent and caused breast tissue to form. The conviction led to the removal of his security clearance and barred him from continuing with his cryptographic consultancy for GCHQ, the British signals intelligence agency. His trial took place only months after the defection to the Soviet Union of Guy Burgess and Donald Maclean, in summer 1951, after which the Foreign Office started to consider anyone known to be homosexual as a potential security risk. Turing was denied entry into the United States after his conviction in 1952, but was free to visit other European countries. The psychological toll of this treatment and the loss of his career were profound, yet he continued to work on abstract mathematics and biological problems.
The Apple And The End
On the 8th of June 1954, at his house at 43 Adlington Road, Wilmslow, Turing's housekeeper found him dead. A post mortem was held that evening, which determined that he had died the previous day at age forty-one with cyanide poisoning cited as the cause of death. When his body was discovered, an apple lay half-eaten beside his bed, and although the apple was not tested for cyanide, it was speculated that this was the means by which Turing had consumed a fatal dose. The inquest was held the following day, which determined the cause of death to be suicide. Turing's brother, John, identified the body the following day and took the advice given by Franz Greenbaum to accept the verdict of the inquest. Turing's mother was on holiday in Italy at the time of his death and returned home after the inquest. She never accepted the verdict of suicide. Philosophers and biographers have questioned the suicide thesis, suggesting an alternative explanation for the cause of death: the accidental inhalation of cyanide fumes from an apparatus used to electroplate gold onto spoons. Turing had such an apparatus set up in his tiny spare room. The potassium cyanide was used to dissolve the gold. Turing also habitually ate an apple before going to bed, and it was not unusual for the apple to be discarded half-eaten. Turing's mother believed that the ingestion was accidental, resulting from her son's careless storage of laboratory chemicals. Turing biographer Andrew Hodges theorised that Turing deliberately made his death look accidental in order to shield his mother from the knowledge that he had killed himself.
The Pardon And The Legacy
In August 2009, British programmer John Graham-Cumming started a petition urging the British government to apologise for Turing's prosecution as a homosexual. The petition received more than 30,000 signatures. The prime minister, Gordon Brown, acknowledged the petition, releasing a statement on the 10th of September 2009 apologising and describing the treatment of Turing as appalling. On the 24th of December 2013, Queen Elizabeth II signed a pardon for Turing's conviction for gross indecency, with immediate effect. Announcing the pardon, Lord Chancellor Chris Grayling said Turing deserved to be remembered and recognised for his fantastic contribution to the war effort and not for his later criminal conviction. The Alan Turing law is now an informal term for the law in the United Kingdom, contained in the Policing and Crime Act 2017, which serves as an amnesty law to retroactively pardon men who were cautioned or convicted under historical legislation that outlawed homosexual acts. The law applies in England and Wales. Due to his repeated attempts to bring attention to the issue, John Leech is now regularly described as the architect of Turing's pardon and subsequently the Alan Turing Law, which went on to secure pardons for 75,000 other men and women. Turing's portrait appears on the Bank of England £50 note, first released on the 23rd of June 2021 to coincide with his birthday. The audience vote in a 2019 BBC series named Turing the greatest scientist of the 20th century, cementing his legacy as a man who changed the world.