Alan Mathison Turing was born in London in a nursing home on the 23rd of June 1912. He was the youngest in a family of two boys. His mother was born in Ireland (Ethel Sara) and his father was a government official in the British colony of India. At nine years of age he was sent to preparatory boarding school, Hazlehurst, in Sussex. When he finished prepatory he moved to Sherborne school in the town of Sherborne. Alan Turing was gay at a time when homesexual activity was outlawed in England. Christopher, an older student at Sherborne School in Dorset, was also interested in math. Turing harbored feelings toward Christopher, though Turing believed his love was not reciprocated. Christopher died at a young age while still in school. Turing had been told before Christopher's death that his friend was sick and to prepare for the worst. Christopher's death did spur Turing to pursue mathematics in the hope that he could understand whether part of Christopher could somehow live on without his body. In the year after his death, Turing wrote an essay in which he discussed how the soul might survive after death with a nod to the new field of quantum mechanics.
Shortly after World War II, Alan Turing was awarded an Order of the British Empire for his work. For what would have been his 86th birthday, Turing biographer Andrew Hodges unveiled an official English Heritage blue plaque at his childhood home. In June 2007, a life-size statue of Turing was unveiled at Bletch Park, in Buckingham shire, England. A bronze statue of Turing was unveiled at the University of Surrey on October 28, 2004, to mark the 50th anniversary of his death. Additionally, the Princeton University Alumni Weekly named Turing the second most significant alumnus in the history of the school - James Madison held the number 1 position.
Turing was honoured in a number of other ways, particularly in the city of Manchester, where he worked toward the end of his life. In 1999, Time magazine named him one of its "100 Most Important People of the 20th century," saying, "The fact remains that everyone who taps at a keyboard, opening a spreadsheet or a word-processing program, is working on an incarnation of a Turing machine." Turing was also ranked 21st on the BBC nationwide poll of the "100 Greatest Britons" in 2002. By and large, Turing has been recognised for his impact on computer science, with many crediting him as the "founder" of the field.
Following a petition started by John Graham-Cumming, then-Prime Minister Gordon Brown released a statement on September 10, 2009 on behalf of the British government, which posthumously apologized to Turing for prosecuting him as a homosexual. "Thousands of people have come together to demand justice for Alan Turing and recognition of the appalling way he was treated," Brown wrote in the statement. "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.
"This recognition of Alan's status as one of Britain's most famous victims of homophobia is another step towards equality and long overdue. But even more than that, Alan deserves recognition for his contribution to humankind," Brown stated. "It is thanks to men and women who were totally committed to fighting fascism, people like Alan Turing, that the horrors of the Holocaust and of total war are part of Europe's history and not Europe's present. 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."
In 2013, Queen Elizabeth II posthumously granted Turing a rare royal pardon almost 60 years after he committed suicide. Three years later, on October 20, 2016, the British government announced “Turing’s Law” to posthumously pardon thousands of gay and bisexual men who were convicted for homosexual acts when it was considered a crime. According to a statement issued by Justice Minister Sam Gaiman, the law also automatically pardons living people who were “convicted of historical sexual offences who would be innocent of any crime today. Alan Turing was a mathematician, cryptographer, and a pioneer of computer science. Today, Turing may best be known for his work at Bletchley Park during World War II, and his part in breaking the German Enigma code. Yet by this time Turing was already well known as a mathematician. As a young man, his idea of a 'Universal Machine', a hypothetical type of computer, resolved one of the most important problems in 20th century mathematics.
The 'Decision Problem', or 'Entscheidungsproblem' in the original German, was initially expressed in 1900 as part of the famous 'Hilbert Problems'- 23 unsolved problems in mathematics, set by David Hilbert as the most important mathematical challenges for the 20th century. In them, Hilbert asked whether we could find a set of 'basic truths' (or 'axioms') from which we could prove all statements in mathematics, without giving any contradictory answers such as 1=0. Hilbert also asked whether there was an algorithm that could determine if a statement was true or false, even if no proof or disproof was known. In other words, Hilbert was asking whether mathematics was 'complete', 'consistent' and 'decidable'.
The first two questions were answered in 1930 by Kurt Gödel who discovered that it was impossible for any set of axioms in arithmetic to be both complete and consistent. This was a major blow for Hilbert's dream. However, the third question, that of whether mathematics was decidable, was still open and would remain so for another six years. So it was, in the Spring of 1935, a young Masters student at King's College, Cambridge, decided to take on the remaining question of decidability.
Alan Turing was born on the 23rd of June 1912. He spent his childhood in Hastings and Sherborne in Dorset, where he attended Sherborne School. Gifted at maths and science, Turing went on to study mathematics at Cambridge. It was there, inspired by the lectures of Max Newman, that Turing decided to take on the Decision Problem.
Turing imagined a hypothetical machine, (now called a 'Turing machine' that would read a tape of symbols, one at a time, then either rewrite or erase the symbol, before then shifting the tape to the left or right. In fact, originally Turing describes a person slavishly performing these operations. He called this person the 'computer'.
Some Turing machines would run forever, some would halt quite quickly, and for others it depended on the input. Turing asked if some method existed that always allowed us to determine whether a computer program and input would eventually halt, or run forever. He proved that a general algorithm to solve this problem, for all possible program and input pairs, cannot exist - making it an example of an undecidable problem. An astounding example that disproved Hilbert's question on deniability. https://youtu.be/AgW6HplOZV0