Reference Articles on Turing

The Turing Test

By Jack Copeland

© Copyright B.J. Copeland, July 2000

The Turing test involves a computer, a human interrogator and a human foil. The interrogator attempts to determine, by asking questions of the other two participants, which is the computer. All communication is via keyboard and screen. The interrogator may ask questions as penetrating and wide-ranging as he or she likes, and the computer is permitted to do everything possible to force a wrong identification. (So smart moves for the computer would be to say 'No' in response to 'Are you a computer?' and to follow a request to multiply one huge number by another with a long pause and an incorrect answer.) The foil must help the interrogator to make a correct identification. A number of different people play the roles of interrogator and foil, and if sufficiently many interrogators are unable to distinguish the computer from the human being then it is to be concluded that the computer thinks.


Here is Turing's example of an exchange that might occur during the test.

Interrogator In the first line of your sonnet which reads 'Shall I compare thee to a summer's day', would not 'a spring day' do as well or better?

Computer It wouldn't scan.

Interrogator How about 'a winter's day'? That would scan all right.

Computer Yes, but nobody wants to be compared to a winter's day.

Interrogator Would you say Mr. Pickwick reminded you of Christmas?

Computer In a way.

Interrogator Yet Christmas is a winter's day, and I do not think Mr Pickwick would mind the comparison

Computer I don't think you're serious. By a winter's day one means a typical winter's day, rather than a special one like Christmas.


A famous objection to the Turing test is John Searle's Chinese Room argument. More information about the Chinese Room objection can be found in Copeland, B.J. 'The Curious Case of the Chinese Gym', Synthese vol. 95 (1993) pp.173-86.

More information about the Turing test can be found in the Archive reference article 'What is Artificial Intelligence?'.


(Illustration by Ann Witbrock; from Copeland, B.J., Artificial Intelligence Blackwell Publishers, Oxford, 1993.)