Alan Turing in 1951, the year after his imitation game paper appeared. Image source. Licence.
Alan Turing opened his 1950 paper with a question about whether machines can think. He then proposed setting it aside. Instead of trying to settle the meaning of thinking, he described an imitation game in which a judge makes a decision from written replies.
His starting game had a man and a woman answering a judge who could see neither. One player tried to mislead the judge and the other tried to help. Turing asked what would happen if a machine took the place of the first player. The change gave readers something to consider in terms of what a judge could observe.
A test of behavior left other questions open
Turing also considered objections and described the possibility of building a machine that could learn instead of programming an adult mind directly. The paper is an argument about what a future computer might do. It never reports a machine passing the game.
The proposal is still useful when a fluent conversation feels like evidence of something deeper. To understand what the conversation establishes, start with what the judge was able to observe and which abilities the exchange actually tested.