Turing, Alan
British Mathematician and Cryptanalyst 1912–1954
In the October 1950 issue of Mind, the brilliant thinker Alan Turing wrote, "We may hope that machines will eventually compete with men in all purely intellectual fields." Turing believed that machines could mimic the processes of the human brain but acknowledged that people would have difficulty accepting such a machine—a problem that still plagues artificial intelligence today.
In a footnote to his 1936 paper on computable numbers, Alan Turing proposed a machine that could solve mathematical problems—a model for what later would become the modern computer.Turing also proposed a test to measure whether a machine could be considered "intelligent." The widely acclaimed "Turing test" involved a connecting a human by teletype (later a computer keyboard) to either another human or a machine. The first human would then ask questions that are translated through these mechanical links. If the respondent on the other end was indeed a machine, but the human asking questions could not tell whether the responses came from a human or machine, then the machine should be regarded as intelligent.
While attending graduate school in mathematics, Turing wrote On Computable Numbers (1936), in which he described hypothetical devices (later dubbed "Turing machines") that presaged today's computers. A Turing machine could perform logical operations and systematically read, write, or erase symbols written on paper tape.
Upon completing his doctorate at Princeton University in 1938, Turing was invited to the Institute of Advanced Studies (also at Princeton) to become assistant to John von Neumann, the brilliant mathematician, synthesizer, and promoter of the stored program concept. Turing declined and instead returned to Cambridge, England. Turing began to work for the wartime cryptanalytic headquarters at Bletchley Park, halfway between Oxford and Cambridge, after the British declared war with Germany on September 3, 1939.
At Bletchley Park, Turing and his colleagues utilized electric and mechanical forms of decryption to break the code of the Enigma cipher machines, on which almost all German communications were enciphered (computed arithmetically). Turing helped construct decoders (called Bombes) that could more rapidly test key codes until correct combinations were found, cutting the time it took to decipher German codes from weeks to hours. As a result, many Allied convoys were saved, and it has been estimated that World War II might have lasted 2 more years if not for the work at Bletchley Park.
Turing's life was not without tumult or a sad conclusion. In 1952, Turing was tried and convicted of "gross indecency" for being homosexual. He was sentenced to probation and hormone treatments. In June 1954, he died from cyanide poisoning. Although he possessed the cyanide in connection with chemical experiments he was performing, it is widely believed he committed suicide.
Turing's life has inspired writers, artists, and sculptors. Breaking the Code, a play based on his life, opened in London in 1986. Although the dialogue and scenes are mostly invented, the play ably conveys the remarkable life of this extraordinary man.
Computers, Evolution of Electronic; Cryptology.
Bibliography
Hinsley, F. H., and Alan Stripp. Codebreakers. New York: Oxford University Press, 1993.
Hodges, Andrew. Alan Turing: The Enigma. New York: Simon & Schuster, 1983.
Turing, Alan. "Computing Machinery and Intelligence." Mind 59, no. 236 (1950):433–460.
Williams, Michael R. A History of Computing Technology. Englewood Cliffs, NJ: Prentice Hall, 1985.
Internet Resources
The Alan Turing Home Page. Ed Andrew Hodges. <http://www.turing.org.uk/turing /index.html>.
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