The basics
The Turing test is a 1950 thought experiment by Alan Turing: if a person chatting by text cannot tell a machine from a human, the machine passes.
Alan Turing, the British mathematician who helped crack wartime codes, asked in 1950 whether machines could think. Instead of defining 'think,' he proposed a game. A judge exchanges typed messages with a hidden human and a hidden computer. If the judge cannot reliably tell which is which, the computer wins.
The test is clever because it sidesteps philosophy. It measures behavior, not inner experience. For decades it was the most famous benchmark in AI, and chatbots that fooled judges for a few minutes made headlines. Turing himself called it the 'imitation game.'
Today many researchers see it as a weak test. Modern chatbots can hold a convincing text conversation, yet still make basic reasoning errors. Passing shows a machine can imitate people, not that it understands. Newer benchmarks measure specific skills instead.
If you spent ten minutes text-chatting with an online support agent and honestly could not tell whether it was a person, that agent passed a casual version of the Turing test.