Turing, Alan Mathison (1912–1954)

English mathematician and logician. In 1936 he described a ‘universal computing machine’ that could theoretically be programmed to solve any problem capable of solution by a specially designed machine. This concept, now called the Turing machine, foreshadowed the digital computer.

Turing is believed to have been the first to suggest (in 1950) the possibility of machine learning and artificial intelligence. His test for distinguishing between real (human) and simulated (computer) thought is known as the Turing test: with a person in one room and the machine in another, an interrogator in a third room asks questions of both to try to identify them. When the interrogator cannot distinguish between them by questioning, the machine will have reached a state of humanlike intelligence.

Turing was born in London and studied at Cambridge. During World War II he worked on the Ultra project in the team that cracked the German Enigma cipher code. After the war he worked briefly on the project to design the general computer known as the Automatic Computing Engine, or ACE, and was involved in the pioneering computer developed at Manchester University from 1948.

Turing was concerned with mechanistic interpretations of the natural world and attempted to erect a mathematical theory of the chemical basis of organic growth. He was able to formulate and solve complicated differential equations to express certain examples of symmetry in biology and also certain phenomena such as the shapes of brown and black patches on cows.