Can machines think? That was the question posed by the great mathematician Alan Turing. Half a century later six computers are about to converse with human interrogators in an experiment that will attempt to prove that the answer is yes.
In the Turing test a machine seeks to fool judges into believing that it could be human. The test is performed by conducting a text-based conversation on any subject. If the computer"s responses are indistinguishable from those of a human, it has passed the Turing test and can be said to be "thinking".
No machine has yet passed the test devised by Turing, who helped to crack German military codes during the Second World War. But at 9am next Sunday, six computer programs - "artificial conversational entities" - will answer questions posed by human volunteers at the University of Reading in a bid to become the first recognised "thinking" machine. If any program succeeds, it is likely to be hailed as the most significant breakthrough in artificial intelligence since the IBM supercomputer Deep Blue beat world chess champion Garry Kasparov in 1997. It could also raise profound questions about whether a computer has the potential to be "conscious" - and if humans should have the "right" to switch it off.