Alan Turing Centenary

2012 is the centenary of the birth of Alan Turing who was born in London on June 23, 1912. Turing was one of the great intellects of the 20th century, and his accomplishments include cracking the codes used by the German Enigma machine in WWII. He died in 1954, leaving behind a legacy that still permeates the computer industry.

Alan Turing 1951

In 1936, Turing developed the concept for a “Turing machine“, which are “simple abstract computational devices intended to help investigate the extent and limitations of what can be computed.” A Turing Machine is not a physical entity, rather it is a mathematical object.

The architecture is simply described, and the actions that may be carried out by the machine are simple and unambiguously specified. Turing recognized that it is not necessary to talk about how the machine carries out its actions, but merely to take as given the twin ideas that the machine can carry out the specified actions, and that those actions may be uniquely described.

Over on the mainland, the Germans increased their military capabilities and, the Poles

Reconstructed British Bombe at Bletchley Park museum.

became increasingly nervous. Throughout the 1930s, they worked on methods to decipher the encryption used by the encoding machine Enigma. In 1939, the work was moved to England, and Alan Turing became instrumental in the creation of the Enigma Bombe, enabling the Allies to be anticipate German troop movement. He continued his work with military intelligence, and the winning of the encryption/decryption war was one one the significant advantages of the Allies.

Following the war, his interest in the philosophy of computing led to the publication in 1950 of a paper in Mind, titled simply “Computing Machinery and Intelligence“.

I propose to consider the question, “Can machines think?” This should begin with definitions of the meaning of the terms “machine” and “think.” The definitions might be framed so as to reflect so far as possible the normal use of the words, but this attitude is dangerous, If the meaning of the words “machine” and “think” are to be found by examining how they are commonly used it is difficult to escape the conclusion that the meaning and the answer to the question, “Can machines think?” is to be sought in a statistical survey such as a Gallup poll. But this is absurd. Instead of attempting such a definition I shall replace the question by another, which is closely related to it and is expressed in relatively unambiguous words. The new form of the problem can be described in terms of a game which we call the ‘imitation game.” It is played with three people, a man (A), a woman (B), and an interrogator (C) who may be of either sex. The interrogator stays in a room apart front the other two. The object of the game for the interrogator is to determine which of the other two is the man and which is the woman. He knows them by labels X and Y, and at the end of the game he says either “X is A and Y is B” or “X is B and Y is A.” The interrogator is allowed to put questions to A and B. We now ask the question, “What will happen when a machine takes the part of A in this game?” Will the interrogator decide wrongly as often when the game is played like this as he does when the game is played between a man and a woman? These questions replace our original, “Can machines think?”

The Turing Test” is behind much of the philosophy of artificial intelligence over 60 years later. In essence, the question asks—at what point can it be said that machines have reached a level where their intelligence is indistinguishable from that of humans?

His contributions to computing may have been even greater if much of his work had none been conducted, by necessity, in secrecy during the war. At the time of his arrest, he had turned his attention to mathematical models of biological morphogenesis.

In 1952, Turing was arrested for being a homosexual and his security clearance for the British Military was revoked. He avoided jail by agreeing to a year of oestrogen injections  designed to decrease his libido. In 1954, he died by eating an apple poisoned with cyanide, an action generally accepted to be by his own hand.

In 2009, 55 years after his death, he received an apology from Gordon Brown, Prime Minister of the UK .

This year has seen a movement to have him officially pardoned for his arrest in 1952, a request that has so far been denied by Justice Minister Tom McNally.

Remember Alan Turing. Without his contribution you might be using a computer with a swastika in the corner.

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