Alan Turing

“The allied invasion of occupied France was the beginning of the end.” “The Nazis spreading themselves over too many fronts lead to their own defeat.” “The entrance of the Americans into the conflict turned the tide.” Sound like familiar explanations for the allied victory in World War Two? How about this one: “The war was won thanks to a mild mannered young Briton named Alan Turing, who liked to run marathons and just so happened to be really good at math.” Not so familiar, but in the minds of computer scientists everywhere, this statement is just as valid.

Early life

Turing was born on June 23, 1912 to parents of England’s middle class. The second of two boys, Turing showed a remarkable aptitude for mathematics from a young age. According to his mother, Edith, he could recognize the significance of numbers long before he could read. His early love of math eventually matured into a highly developed sense of logic, often leading to trouble with his tutors, who quickly became frustrated by his strict adherence to the literal meaning of instructions, or an unwillingness to “read between the lines.” In his book, The man who knew too much, David Leavitt recounts an anecdote about a time when Turing found himself in hot water with the military for not signing his identification card. Upon questioning, Turing simply stated that he had been told not to write on his card, and so he didn’t.

Turing’s father, Julius, was a member of the British Civil Service in India, and while the family returned to England shortly before Turing was born, his parents soon returned to India. Insistent that Asia was no place for a young English boy to grow up, Turing’s parents placed their children in foster homes. While some Turing historians believe that the loneliness of growing up away from his parents influenced his desire to rationalize the human mind and thought, others point to the tragic death of a close school mate to bovine tuberculosis as the motivating force behind his attempted rationalization of consciousness.

Regardless of the motivation, it was Turing’s desire to explain thought in a mathematical sense which lead to his research into computers, and would help him to become, as Michael Domaratzki, an assistant professor in the University of Manitoba’s department of computer science, describes “one of the most important founding fathers of modern computer science.”

The college years

After leaving elementary school, Turing applied for a fellowship at the University of Cambridge’s Trinity College, a world-renowned math institution at the time. After suffering two rejections from Trinity, Turing successfully applied to Kings College, where he found an environment which allowed him to thrive, despite retaining the social awkwardness of his youth. Following the completion of his degree requirements, Turing stayed on at Kings College as a tutor, until the Second World War changed his life forever.


As terrifying, advanced and efficient as the Nazi war machine was, their codes and cryptology, used to direct resources on the battlefield and keep in communication with the high command, were even more effective. Great Britain realized early on that if they were going to stay one step ahead of their enemy, they would need to break the Nazi codes. To that effect, The British government established the Code and Cypher School, based out of Bletchley Park in Buckinghamshire, which recruited anyone who might have an aptitude at code-breaking, including: mathematicians, Egyptologists and even chess champions.

It was at Bletchley Park where Turing developed algorithms, based on his earlier studies of computer science at Cambridge, which would eventually allow the allies to crack the Enigma code, the communications encryption used by the German Navy to send instructions to its U-boats in the North Atlantic.

Contributions to science

While Turing’s contribution to the war effort was undeniably huge, leading the British crown to make him an officer of the British Empire, ask a computer scientist about Turing’s contributions and the war effort may never get mentioned.

“He is seen as a mythical figure in computer science” says Domaratzki. “They don’t make them like Turing anymore. He made so many contributions to computing and code-cracking, but he was also involved with advancements in computational mathematics and mathematical biology.” But if you had to pinpoint Turing’s greatest accomplishment, according to Domaratzki at least, it would have to be the Turing Machine.

Paradoxically, calling the Turing Machine a machine is quite wrong. “It’s more a [theoretical] model of what computers are capable of doing, [ . . . ] something you write down as a formula rather than something you build,” says Domaratzki, although it is interesting to note that Turing Machines have been built, and out of all kinds of materials, such as Lego and Mecano (a thorough search of yields some interesting videos of Turing Machines in action.) Amazingly, more than 70 years after its inventor first published on the idea of the Logic Computing Machine, as the Turing Machine was called by its modest inventor, computer scientists still consider it relevant.

In the 1930s, when computers were more the realm of science fiction than science fact, Turing used the thought experiment of the Turing Machine to define the limits of what algorithms, or the instructions that computers use to complete tasks, should be capable of, also known as the concept of undecidability. Put another way, he demonstrated that there are some things that computers will never be able to do, almost a half century before the advent of the personal computer. As an example, Domaratzki points to the P versus NP problem, proposed by Stephen Cook, of the University of Toronto in 1973.

The P versus NP problem asks the question “is it faster to prove that a given answer to a question is correct, or solve the problem and find the correct answer?” While the difference may seem subtle to non-computer scientists, according to the limits set out by Turing and his Logic Computing Machine, the problem may be unsolvable — so unsolvable that the Clay Mathematics Institute of Cambridge Massachusetts has offered a prize of US$1,000,000 to anyone providing the answer. The prize has yet to be claimed.

Unfortunately, despite his contributions to computer science and the war effort, Turing’s life ended in tragedy. In 1952 Turing admitted to police, who were investigating a robbery at his home, that a man he had been intimate with might be aquatinted with the robber. As homosexuality was a crime in Great Britain at the time, Turing was convicted of “gross indecency” and given the choice between prison and hormone treatments. Seeing no other option, Turing submitted to regular injections of estrogen, an ill conceived and cruel “homosexuality cure” popular at the time. Turing committed suicide two years later.

Fifty-five years after his death, on Sept. 10, 2009 the British prime minister, Gordon Brown, responding to a petition calling for a formal apology for the treatment of Turing, issued a statement, in which he called the treatment of Turing “appalling.” It ends with the line “[ . . . ] we’re sorry, you deserved so much better.”

When asked what the Turing apology means to him, Domaratzki reflects for a moment, “[ . . . ] It won’t change what he contributed [to computer science], what he accomplished, how he was treated or the tragedy of his death, but it’s amazing.”