## Alan Turing Essay Writing Contest: First Place, Satarupa Guha

Posted on April 16, 2012

On a serene morning of June, 1954, a half-eaten apple lay beside a man, convicted of the death of the father of computer science, Alan Turing. His demise, believed to be the result of cynanide poisoning, was a rather bleak accolade for the man who happened to be one of the greatest pioneers of the computer field. Mathematician, logician, crystanalyst, computer scientist : Alan Turing encompassed an wider spectrum of proficiency than that proclaimed by these few mere tags.

Born of British parents, Julius Mathison Turing, member of the Indian Civil Service, and Ehel Sara Stoney, on June 23, 1912 in England, Alan Turing was admitted to St. Michaels at the age of six and later to Sherbourne School. From the very onset of his school education, he showed signs of genius and an unabashed interest for science in general, amd mathematics in particular. His first day of term coincided with the 1926 General Strike in Britain, but so determined was he to attend that he rode his bicycle unaccompanied more than 60 miles to school, stopping overnight at an inn. However when it came to skills of the right brain, he suffered miserably. He was criticised for his handwriting, struggled at English, so much so that his headmaster once wrote to his mother:

“If he is to stay at Public School, he must aim at becoming educated. If he is to be solely a Scientific Specialist, he is wasting his time at a Public School.”

However, he won every possible prize for mathematics while at school, and learnt deep mathematics on his own. He found special interest in Chemistry too and carried out self-designed experiments which greatly displeased his teachers. Flowering under the strict discouragement of his instructors, Turing continued undeterred to spread himself into the more prolific realms of scientific knowledge. While still being a school student, he had already read Einstein’s papers on relativity and Eddington’s quantum mechanics. Not only did he grasp them, he even extrapolated Einstein’s questioning of Newton’s laws of motion from a text in which this was never made elicit.

Thankfully for Turing, Cambridge proved to be a better place to fit in for unconventional people like him. Entering into King’s College, Cambridge to study mathematics, he could now seamlessly pursue his interest in mathematical logic. It was here that he developed a penchant for recreating the works of previous scientists. He proved the central limit theorem, despite the fact that he had failed to find out that it had already been proved in 1922 by Lindenberg. This dissertation earned him the honour of being elected a fellow at King’s in the same year.

In his path-breaking paper “On Computable Numbers, with an Application to the Entscheidungsproblem” (submitted on 28 May 1936) Turing reformulated Kurt Gödel’s 1931 results on the limits of proof and computation, replacing Gödel’s universal arithmetic-based formal language with what became renowned as Turing machines. He proved that such a simple formal machine would be capable of performing any conceivable mathematical computation if it could be represented as an algorithm. Perhaps the most remarkable feature of Turing’s work on Turing machines was that he was describing a modern computer before technology had reached the point where construction was a realistic proposition. He went on to prove that there was no solution to the Entscheidungsproblem by first showing that the halting problem for Turing machines is undecidable. Albeit, his proof was published after Alonzo Church’s equivalent proof, Turing was unaware of Church’s work at the time.

From 1936 to 1938 he was actively doing research work at the Institute for Advanced Study, Princeton, under Alonzo Church. While at Princeton Turing had played with the idea of constructing a computer. Once back at Cambridge in 1938 he started to build an analogue mechanical device to investigate the Riemann hypothesis, which many consider today the biggest unsolved problem in mathematics. In addition to his purely mathematical work, he studied cryptology and also built three of four stages of an electro-mechanical binary multiplier.In June 1938 he obtained his PhD from Princeton.His dissertation (Systems of Logic Based on Ordinals) ushered in the concept of ordinal logic and the notion of relative computing, where Turing machines are augmented with oracles, allowing a study of problems that cannot be solved by a Turing machine. Turing machines remain to this day a pivotal object of study in theory of computation.

During the Second World War, Turing was a leading participant in the breaking of German ciphers at Bletchley Park, the site of the United Kingdom’s main decryption establishment, the Government Code and Cypher School, where ciphers and codes of several Axis countries were decrypted.Turing’s brilliant ideas in solving codes, and developing computers to assist break them, may have saved more lives of military personnel in the course of the war than any other.Together with another mathematician W G Welchman, Turing developed the ‘Bombe’, a machine based on earlier work by Polish mathematicians, which from late 1940 was decoding all messages sent by the ‘Enigma’ machines, which the German navy used for encoding their messages. It was an an extremely challenging task to decode them as the ‘Enigma’ was able to generate a constantly changing code that was impossible for the code breakers to decipher in a timely fashion. In July 1942, Turing devised a technique termed ‘Turingery’ for use against the Lorenz cipher messages produced by the Germans’ new Geheimschreiber (secret writer) machine. Turing and his fellow scientists worked with a device called COLOSSUS. The COLOSSUS quickly and efficiently deciphered the German codes. COLOSSUS was essentially a bunch of servomotors and metal, but it was one of the first steps toward the digital computer.Turing travelled to the United States in November 1942 and worked with U.S. Navy cryptanalysts on Naval Enigma and bombe construction in Washington, and assisted at Bell Labs with the development of secure speech devices.

After World War II, Turing took up long distance running as a means of relieving the stress that he had been experiencing lately and realised that he actually excelled at it. He obtained record times in both the 3 and 10 mile races in the Walton Athletic Club. Typical of his logical nature, his sometimes used his athletic ability to run between locations for his lectures.

Turing went on to work for the National Physical Laboratory (NPL) and continued his research into digital computers. Here he worked on developing the Automatic Computing Engine (ACE), one of the first attempts at creating a true digital computer. It was during this time that he began to explore the relationship between computers and nature. He wrote a paper called “Intelligent Machinery” which was later published in 1969. This was one of the first times the concept of artificial intelligence was raised. He once joked-

“No, I’m not interested in developing a powerful brain. All I’m after is just a mediocre brain, something like the President of the American Telephone and Telegraph Company.”

Turing believed that machines could be created that would reflect the intricate processes of the human brain. He discussed the possibility of such machines, acknowledging the difficulty people would have accepting a machine that would pose a threat to their own intelligence, a problem that still plagues artificial intelligence today. He wrote a paper in 1950 describing what is now known as the “Turing Test.” The test consisted of a person asking questions via keyboard to both a person and an intelligent machine. He believed that if the person could not tell the machine apart from the person after a reasonable amount of time, the machine was somewhat intelligent. This test has become the ultimate test of the artificial intelligence community.

An aspect of his life that most often remains unacknowledged is his contribution to Biology. By 1951 he was working on the application of mathematical theory to biological forms. In 1952 he published the first part of his theoretical study of morphogenesis, the development of pattern and form in living organisms.He was interested in how and why organisms developed particular shapes. There are millions of cells in a person or a tree, and yet all know what shape to be. Turing yearned to unravel this mystery.

Alan Turing would probably have laughed off the idea of being a philosopher. He called himself a mathematician. But his 1950 paper ‘Computer machinery and Intelligence’ has become one of the most cited works in modern philosophical literature. He brought the new mathematical concept of computability into traditional problems of mind and body, free-will and determinism.

A victim of social stigma and religious prejudice, Alan Turing was placed under house arrest and forced to take regular oestrogen injections after being convicted of homosexuality, then a punishiable offence under British law. He is believed to have brought death upon himself at the age of 41 through a self-administered dose of poison, although his mother maintained that his death was caused by a chemical experiment that went awfully wrong. Whatever the reason be, his death went on to resonate some of his own words-

” Science is a differential equation. Religion is the boundary condition.”

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