Excerpt:
Turing held that computers would in time be programmed to acquire abilities rivalling human intelligence.
As part of his argument Turing put forward the idea of an 'imitation game', in which a human being and a computer would be interrogated under conditions where the interrogator would not know which was which, the communication being entirely by textual messages. Turing argued that if the interrogator could not distinguish them by questioning, then it would be unreasonable not to call the computer intelligent.
Turing's 'imitation game' is now usually called 'the Turing test' for intelligence.