Alan Turing appears now as the Founder of Computer Science, but these words were not spoken in his own lifetime.
Alan Mathison Turing was born on 23 June 1912 in a nursing home in Paddington, London, the second and last child of Julius Mathison and Ethel Sara Turing.
His boyhood scientific interests were a trial to his mother whose perpetual terror was that he would not be acceptable to the English Public School. Despite this, he was successfully entered for Sherborne School, and in the midst of the General Strike of 1926, Alan Turing started at Sherborne
Sherborne School was a classic English public school. The 'Public schools' took their name from the original endowments which had established them for public education, but they had been turned into private schools for the upper middle class, and trained boys for the more gentlemanly forms of business and for imperial administration.
Alan Turing remained in a private world of science.
The English report says: "I can forgive his writing, though it is the worst I have ever seen, and I try to view tolerantly his unswerving inexactitude and slipshod, dirty, work, inconsistent though such inexactitude is in a utilitarian; but I cannot forgive the stupidity of his attitude towards sane discussion on the New Testament." Bottom of the class.
He did better in Latin, only second from bottom: "He ought not to be in this form of course as far as form subjects go. He is ludicrously behind".
The mathematics and science reports were better but still complained: 'His work is dirty'.
The headmaster soon reported: "If he is to be solely a Scientific Specialist, he is wasting his time at a Public School." The assessment of his establishment was almost correct. Turing's private notes on the theory of relativity showed a degree-level appreciation, yet he was almost prevented from taking the School Certificate lest he shame the school with failure.
In 1928 Alan Turing was allowed to enter the sixth form of Sherborne School and to specialize in mathematics and science. In the Science Sixth he met Christopher Morcom, another outstanding student and enthusiast for science. He gave Turing a vital period of intellectual companionship, which ended with Morcom's sudden death in February 1930.
As an undergraduate at King's College, Cambridge from 1931, he entered a world more encouraging to free-ranging thought. His association with the so-called anti-War movement of 1933 did not develop into Marxism, nor into the pacifism of his friend and occasional lover James Atkins, then a fellow undergraduate mathematician, later musician.
Turing's progress seemed assured, A distinguished degree in 1934 followed by a Fellowship of King's College in 1935 and a Smith's Prize in 1936 for work on probability theory, and he might then have seemed on course for a successful career as a mildly eccentric King's don engaged in pure mathematics. His uniqueness of mind, however, drove him in a direction none could have foreseen.
Turing became very interested in the problem of computability. He wanted to find out what a computation is and whether a computation can in fact be carried out. To answer these questions Turing extracted from the ordinary process of computation the essential parts and formulated these in terms of a theoretical machine, known as the Turing machine. It has been speculated that Turing found in the concept of the Turing machine something that satisfied the problem of the mind brought on by Chistopher Morcom. He expanded this idea to show that there exists a "universal" Turing machine, a machine which can calculate any number and function, given the appropriate instructions.
In September, 1936 Turing enrolled as a graduate student at Princeton University. His Paper, On Computable Numbers. was published near the end of 1936.This paper generated a lot of attention for him and the idea came to mathematician John Von Neumann. Turing obtained his PhD thesis through work that extended his original ideas (Ordinal Logic).
Returning to England and King's College in 1938, he was called on the outbreak of World War II, to serve at the Government Code and Cipher School in Bletchley Park in Buckinghamshire. It was there that Turing led in the successful effort to crack the German "Enigma" code, an effort which was central in the defeat of Nazi Germany.
After the war, Turing joined the National Physical Laboratory to work on the design of a computer. He continued his work at the University of Manchester after 1948. Turing's promising career came to a grinding halt when he was arrested in 1952 for "gross indecency". The penalty for this crime was submission to psychoanalysis and to horrible treatments designed to "cure" the disease.
On the 8th of June 1954, his cleaning lady found him dead. The cause of death was cyanide poisoning. A half-eaten apple was found near him. The coroner's verdict was suicide. Turing's mother always believed that he had accidentally poisoned himself. Possibly, he had planned his death so that she would believe it to have been an accident.