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Introduction A.M. Turing (1912–1954) was an important thinker who laid the foundations of the digital computer, artificial intelligence and mathematical biology. With his Turing machine he enabled Gödel to generalize his incompleteness theorem. After his graduation, Turing was elected fellow of King’s College, Cambridge, in 1935. He devised a hypothetical computer, the Turing machine, that served as an example for the first actual digital computers that were built ten years later. With the Turing machine, Turing made a major contribution to Gödel’s incompleteness theorem that states that Hilbert’s envisioned complete, consistent logical system in which every statement could be proven to be true or false, cannot exist. In 1936 Turing went to A. Church at Princeton, USA, where he wrote a PhD thesis about uncomputable problems and undecidable statements. When the war broke out in 1939, Turing moved to the Government Code and Cypher School (gc&cs) to break the Enigma, the message encoding system used by the German army. The success of his work had a significant impact on the outcome of the Second World War. After the war, Turing worked for the National Physical Laboratory and later for the Computing Machine Laboratory to build the world’s first computers. In the mean time, Turing wrote groundbreaking articles about artificial intelligence and thinking machines. In 1952 Turing was prosecuted for homosexual activity and sentenced to receive “hormone therapy”, according to Copeland “the shabbiest of treatment from the country that he had helped save”. In 1954, Turing died, presumably by taking his own life. Turing had a major influence on the architecture of modern digital computers. His ideas about artificial intelligence and about theoretical biology were way ahead of his time. For instance, Turing emphasized the idea that in order to be intelligent, computers should be able to learn by themselves and to modify their own instructions. However, during the first decades after his death, artificial intelligence was mainly associated with expert systems that have no self-learning capacity at all. The same can be said about his work on theoretical biology, that was taken up by I. Prigogine 15 years after Turing’s death. “The Essential Turing” is a comprehensive book edited by B. Jack Copeland. It contains the most important publications of Turing, with introductions of B. Jack Copeland and the history of the breaking of Enigma. The book includes two documents that have not been printed before, because they were classified until 1995: the history of one of the units of the organisation that worked on the Enigma decryption (Hut 8), written in 1945 by Patrick Mahon and a chapter of the “Treatise on Enigma”, that Turing wrote during the war. The book is divided into five parts: 1) a three-page biography; 2) Computable numbers, about the Turing machine and Gödel’s incompleteness theorem; 3) Enigma; 4) Artificial Intelligence and 5) Artificial Life, with an article about mathematical biology. This review follows Copeland’s division. The complete article can be obteined via the link "print/download PDF version" above. |
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