Turing and the Machine

If necessity is the mother of invention, the computer had twomothers—cryptography and the hydrogen bomb. But therewas only one father: Alan Mathison Turing.

A CHILD OF EMPIRE

Turing was conceived in India, where his father, Julius, was amember of the Indian Civil Service helping to administer thisjewel in the crown of the British Empire; but he was born,on June 23, 1912, in Maida Vale, London, when his parentswere on home leave. He already had a brother, John, born inIndia on September 1, 1908. When Julius returned to Indiatheir mother, Sara, stayed in England with the two boys, butonly until September 1913, when she rejoined her husbandand left the children in the care of a retired army colonel andhis wife, who lived at St. Leonards-on-Sea in Sussex. Therewas a nanny who looked after the two boys and the colonel'sfour daughters, together with another boy whose parents wereoverseas, and later three cousins of Alan and John. Theirmother returned for the summer of 1915, staying with theboys in rented rooms in St. Leonards, and both parents cameto England in the spring of 1916—the first time that Alanreally had an opportunity to get to know his father. At theend of this leave, in August, Julius Turing returned to Indiafor his next three years' tour of duty. John had already beensent away to school at Hazelhurst, in Kent; Alan, havingbeen just one of a motley group of children, now became ineffect the only child of a single parent, who took him almosteverywhere with her, including to the High Anglican churchshe attended (which he hated) and to art classes (she was anaccomplished watercolorist), where he was the darling of thefemale students.

Alan was remembered as a bright, untidy child with a predilectionfor inventing his own words, such as "quockling" todescribe the sound of seagulls and "greasicle" for a gutteringcandle. It was impossible to pull the wool over his eyes—whenhis nanny tried to let him win a game they were playing bymaking poor moves, he saw through the subterfuge and wasinfuriated; when his mother was reading him a story and left adull passage out, he yelled: "You spoil the whole thing." Norwas he ever in any doubt about the accuracy of his own worldview:he knew, for example, that the fruit which tempted Evein the Garden of Eden was a plum. But he never could tell leftfrom right, and marked his left thumb with a red spot so thathe would know which was which.

Having taught himself to read (from a book appropriatelycalled Reading without Tears), Alan first encountered formaleducation at the age of six, when his mother sent him to alocal day school to learn Latin. This failed to stir his interest,but highlighted his great difficulty with the physical processof writing, especially with the ink pens in use at the time. Hiswork was always a mess of scratchy scribbles, crossings-outand blots, reminiscent of nothing so much as the spoof handiworkof Nigel Molesworth in the stories by Geoffrey Willansand Ronald Searle.

Alan's next meeting with his father came in 1919, whenJulius's leave included a holiday in Scotland: here the seven-year-oldboy impressed his family on a picnic by tracking theflights of wild bees to their intersection to find honey. But inDecember both parents sailed for India, and Alan returnedto the colonel's house in St. Leonards while John went backto school in Hazelhurst. The next two years saw a changein Alan. When his mother next returned, in 1921, she foundthat the vivacious and friendly boy she had left in Englandhad become "unsociable and dreamy," while his educationhad been so neglected that at nearly nine he had not learnedhow to do long division. She took him away for a holiday inBrittany, and then to London, where she taught him long divisionherself. She later recalled that when he had been shownhow to find the square root of a number, he worked out forhimself how to find the cube root.

At the beginning of 1922, it was time for Alan to followhis brother John to Hazelhurst, a small school for thirty-sixboys aged from nine to thirteen, with just three teachersand a matron who looked after the boys. The brothers weretogether at Hazelhurst for only one term before John left atEaster for Marlborough College and the public-school educationfor which "prep" schools such as Hazelhurst werepreparing their boys. The same year, Alan was given a bookcalled Natural Wonders Every Child Should Know, by EdwinBrewster. This first encounter with science made a deepimpression on him, especially the way the author likened theworkings of the body, even the brain, to a machine. He wasless impressed by the sporting activities that young Englishgentlemen of the time were expected to enjoy (or at leastendure), and later claimed that he had learned to run fast(he became a very good long-distance runner as an adult)in order to keep away from the ball during hockey. He wasalso disturbed by the imprecision of some of his teachers, andwrote to John that one of them "gave a quite false impressionof what is meant by x." His concern was not for himself, butthat the other boys might be misled.

The summer of 1922 brought the return of Alan's fatheron leave once more, and another happy family holiday inScotland. But in September his parents left him back atHazelhurst, departing down the drive of the school with Sarabiting her lip as she watched her son running futilely afterthe taxi, trying to catch up with them. Bored by school, Alanachieved nothing spectacular in the way of marks, but lovedinventing things and developed a passion for chemistry—whichwas purely a hobby: God forbid that a prep schoollike Hazelhurst should have anything to do with science.Science was almost as conspicuous by its absence at mostpublic schools, so when in the autumn of 1925 Alan surprisedeveryone by doing well in the Common Entrance examinationthat was a prerequisite to the transition, his future presentedhis parents with something of a conundrum. Johnmade an impassioned plea to their parents not to send hisunusual younger brother to Marlborough, which "will crushthe life out of him," and Sara Turing worried that her sonmight "become a mere intellectual crank" if he failed to adaptto public school life. The puzzle of what to do with him wassolved by a friend of hers who was married to a science masterat Sherborne, a school in Dorset established back in 1550 andbrought into the modern public school system in 1869. Thefriend assured Sara that this would be a safe haven for her boy,and Alan started there in 1926.

SHERBORNE

He was due to arrive for the start of the summer term, onMay 3, from Brittany, where his parents were living to avoidpaying British income tax. On the ferry to...