________________________________ From: Robert Paul <rpaul@xxxxxxxx> "Donal wrote >> >> A Turing test is based on the idea, you've got this right, that >> if you talk with the machine can can't tell the difference between >> talking with a machine and talking with a person, you call the >> machine intelligent.>>" Donal did not write this but quoted it; not that it much matters. "John McCreery replied > Could be. Turing's point was that if the machine interacted with humans in > a way indistinguishable from the way other humans did there would be no way > to tell the difference." John was not replying to the words wrongly attributed to me above but to a much longer reply that applied World 1, 2 and 3 thinking to the idea of machines being able to think. Robert refers us to a paper by Turing published in Mind. (This is the same Mind that turned down Popper's 'The Poverty of Historicism' but saw fit for publication Turing's somewhat tenuous thoughts.) Perhaps it was the novelty of computers then that made Mind step back to allow Turing, as an expert in computers, to have his say, even though his paper contains material as dubious as the following:- 9) The Argument from Extrasensory Perception I assume that the reader is familiar with the idea of extrasensory perception, and the meaning of the four items of it, viz., telepathy, clairvoyance, precognition and psychokinesis. These disturbing phenomena seem to deny all our usual scientific ideas. How we should like to discredit them! Unfortunately the statistical evidence, at least for telepathy, is overwhelming. It is very difficult to rearrange one's ideas so as to fit these new facts in. Once one has accepted them it does not seem a very big step to believe in ghosts and bogies. The idea that our bodies move simply according to the known laws of physics, together with some others not yet discovered but somewhat similar, would be one of the first to go. This argument is to my mind quite a strong one. One can say in reply that many scientific theories seem to remain workable in practice, in spite of clashing with ESP; that in fact one can get along very nicely if one forgets about it. This is rather cold comfort, and one fears that thinking is just the kind of phenomenon where ESP may be especially relevant. A more specific argument based on ESP might run as follows: "Let us play the imitation game, using as witnesses a man who is good as a telepathic receiver, and a digital computer. The interrogator can ask such questions as 'What suit does the card in my right hand belong to?' The man by telepathy or clairvoyance gives the right answer 130 times out of 400 cards. The machine can only guess at random, and perhaps gets 104 right, so the interrogator makes the right identification." There is an interesting possibility which opens here. Suppose the digital computer contains a random number generator. Then it will be natural to use this to decide what answer to give. But then the random number generator will be subject to the psychokinetic powers of the interrogator. Perhaps this psychokinesis might cause the machine to guess right more often than would be expected on a probability calculation, so that the interrogator might still be unable to make the right identification. On the other hand, he might be able to guess right without any questioning, by clairvoyance. With ESP anything may happen. If telepathy is admitted it will be necessary to tighten our test up. The situation could be regarded as analogous to that which would occur if the interrogator were talking to himself and one of the competitors was listening with his ear to the wall. To put the competitors into a "telepathy-proof room" would satisfy all requirements. Now where to begin with this? For starters, perhaps someone could explain what is the "overwhelming...statistical evidence..for telepathy"? That there is compelling evidence for E.S.P. is certainly discounted by Sir Karl in 'The Self and Its Brain', but perhaps Popper simply overlooked the simply "overwhelming...statistical evidence"? Whatever the statistical evidence, the paper does not suggest that Turing is much of a philosopher, though admittedly this might said be of many academic philosophers also. Donal London