Tuesday, March 23, 2004

Dyson on the Paranormal Don't miss this fascinating article from Freeman Dyson in the New York Review of Books. Dyson is a professor of physics at Princeton University. The book under review is titled Debunked: ESP, Telekinesis and Other Pseudoscience by Georges Charpak and Henri Broch. This book first appeared in French but has now been translated by Bart K. Holland. Charpak is a Nobel laureate in physics.

Dyson's review is highly favorable, and I look forward to reading the book myself. What is especially interesting, however, are Dyson's speculations on the existence of the paranormal.

The hypothesis that paranormal phenomena are real but lie outside the limits of science is supported by a great mass of evidence. The evidence has been collected by the Society for Psychical Research in Britain and by similar organizations in other countries. The journal of the London society is full of stories of remarkable events in which ordinary people appear to possess paranormal abilities. The evidence is entirely anecdotal. It has nothing to do with science, since it cannot be reproduced under controlled conditions. But the evidence is there. The members of the society took great trouble to interview first-hand witnesses as soon as possible after the events, and to document the stories carefully. One fact that emerges clearly from the stories is that paranormal events occur, if they occur at all, only when people are under stress and experiencing strong emotion. This fact would immediately explain why paranormal phenomena are not observable under the conditions of a well-controlled scientific experiment. Strong emotion and stress are inherently incompatible with controlled scientific procedures. In a typical card-guessing experiment, the participants may begin the session in a high state of excitement and record a few high scores, but as the hours pass, and boredom replaces excitement, the scores decline to the 20 percent expected from random chance.

I am among those who believe that anecdotal evidence counts for very little in these matters. A large number of dubious anecdotes does not impress me any more than small number of dubious anecdotes. Elsewhere in the article, Dyson makes it clear that he believes that all attempts to verify paranormal phenomena scientifically have failed.

Dyson suggests that the anecdotal evidence reveals that these phenomena only manifest themselves when people are under stress and experiencing strong emotion. This, he says, is why science has failed to detect them. That is possible, of course. An alternative explanation, however, is that people seem to experience the paranormal at precisely the times when their judgment is most impaired. The anecdotal evidence of people under severe emotional stress is not especially convincing.

Even the most dogmatic skeptic would not assert that paranormal phenomena can not possibly be real. Rather, the assertion is that there is no good reason for believing that they are.

Dyson considers the existence of paranormal phenomena more likely than I do, but I doubt that he is mkaing major life decisions based on this belief. And wherever you come down on this issue, I think all sensible people can agree with Dyson's conclusion:

Whether paranormal phenomena exist or not, the evidence for their existence is corrupted by a vast amount of nonsense and outright fraud. Before we can begin to evaluate the evidence, we must get rid of the hucksters and charlatans who have turned unsolved mysteries into a profitable business. Charpak and Broch have done a fine job, sweeping out the money-changers from the temple of science and exposing their tricks.


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