Alan Turing is a name many people have heard of, especially after he was selected to appear on the new £50 notes, but not many people know his story. He did a lot for mathematics and computing within his relatively short life and we will try our best to provide an appropriate summary here. We highly recommend people do their own study into this incredible mathematician.
He was born (and raised) in London on June 23rd 1912. From a young age, he showed a particular aptitude for mathematics, solving advanced calculus without studying it before he was even 16. He went on to study mathematics at Cambridge University, where he was awarded first class honours in mathematics. He was later elected as a fellow at King’s for his proof of the central limit theorem in 1935. His work didn’t stop there, though by this time, he had started focusing on mathematics surrounding computational science. In 1936, he published “On Computable Numbers, With an Application to the Entscheidungsproblem”. This paper is the first instance of his ‘Turing machine’. Turing machines are still a central object of study in the theory of computation.
In 1938, Turing began his arguably most famous work breaking German ciphers at Bletchley Park during World War . Historian and wartime codebreaker, Asa Briggs has said “You needed exceptional talent, you needed genius at Bletchley and Turing was that genius”. He began work part-time with the Government Code and Cypher School (GCCS), the British codebreaking organisation. He focussed primarily on cryptanalysis of the Enigma. During his first year working there, he wrote 2 papers, “The Applications of Probability to Cryptography” and “Paper on Statistics of Repetitions”. These papers were so influential that they could not be released until 2012 when they were deemed safe to release without jeopardising current work that the GCCS were doing. In 1946, Turing was appointed an Officer of the Order of the British Empire (OBE) by King George VI for his wartime services even though his work remained secret for many years after. After the war, his attention turned to mathematical biology and he published “The Chemical Basis of Morphogenesis” in January 1952, at the age of 39. This paper is another of his works that is still highly relevant today and is considered a seminal piece of work in mathematical biology. This was not the last of his papers and his work can be purchased in a series of volumes called "Collected Works of A.M. Turing".
In January 1952, Turing’s house was burgled. His partner, Arnold Murray, knew the assailant and they reported the robbery to the police. While reporting the burglary, both were charged with gross indecency due to their homosexuality. Turing pleaded guilty and was granted probation with the condition he be chemically castrated, a process which caused damaging changes to his body. His conviction meant he lost his job at the British Signals Intelligence Agency (formerly the GCCS) though he did keep his academic job. He was found dead in his home on June 8th 1954, at the age of 41 and an inquest ruled his death a suicide. Turing was cremated and his ashes scattered in the gardens of Woking Crematorium.
In 2009, a British Programmer called John Graham-Cumming started a petition urging the British government to apologise for Turing’s prosecution as a homosexual. The prime minister at the time, Gordon Brown, acknowledged the petition and released an apology statement. In 2011, William Jones and MP John Leech began another petition to give Turing a post-humous pardon of his conviction. This was ultimately achieved in 2012, though there were some setbacks and disagreements within parliament. This pardon led to the 2017 “Turing Law” which granted pardons for men who were historically cautioned or convicted for homosexuality.
Alan Turing in 1928, Aged 16
Source: Turing Digital Archive http://www.turingarchive.org/browse.php/K/7/4