Alan M. Turing: I compute, therefore I am thinking?

Alan M. Turing explored the idea of machine intelligence around 1941 and published the paper "Computing Machinery and Intelligence" in 1950.

Turing proposed a thought experiment which he called the imitation game, which has become known as the Turing test.  In it a person called the interrogator conducts interviews with two subjects, a machine and a human being, in a room with two teleprinters (so that the only the text of the interview can be observed). The  interrogator does not know which teleprinter is operated by the machine and which by the human.  If the interrogator cannot determine which subject is the machine, than the machine can be considered intelligent.

One of the first machines that convinced observers that it was intelligent was the 18th century chess player The Turk,which was operated by a small person hiding behind several sliding panels.  Several modern claims have been made of machines convincing observers that they were human, but this usually involved situations where there was only one subject being interviewed and the observer was not aware that he might be conversing with a machine.

The idea that a machine could think led to the field of Artificial Intelligence, which demonstrated how complex many tasks were that had been considered simple.  The techniques used in artificial intelligence research included search trees, language context representation, neural nets, and expert systems; the results of some of this research led to machine translation of human languages, search engines, game-playing machines, voice controlled software and dictation software, and voice and visual recognition.

 A Java version of the ELIZA program (an early program that carried on a conversation with the user and convinced some people that it was human) is available at http://www.chayden.net/eliza/Eliza.html and a web-based version is at http://www-ai.ijs.si/eliza-cgi-bin/eliza_script.  RACTER, a program that produced a rambling nonsense monolog in response to user input, can be found at http://www.myabandonware.com/game/racter-4m#download  (MS-DOS version) or  http://www.mirrors.org/archived_software/www.techknight.com/esa/default.htm (runs under Windows), and a shareware version in Basic can be found at http://www.cs.cmu.edu/afs/cs/project/ai-repository/ai/areas/classics/racter/0.html.