The received wisdom is not the whole story, writes Brian Josephson.

Robert Park¡¯s book is basically an attack on dubious science, which he calls ¡°voodoo science¡±. Categories discussed include: claimed devices or experiments that violate the laws of physics, the devices often generating more energy than is put into them; overstated claims as to the value of particular lines of research (for example, microgravity research in space) and implausible claims of the benefits of particular health remedies.

The author provides entertaining accounts of his involvement with such claims, explaining why he thinks they cannot be taken seriously. He ascribes their prevalence to the way we are primed to detect patterns and then form hypotheses based upon them. Emotional events may result in hypotheses being felt to be indubitably correct, so that we become very reluctant to abandon them even in the face of clear contrary evidence. This leads to the widespread acceptance of beliefs whose soundness is in considerable doubt, an undesirable situation that can be combated by the clarifying processes of science. There, beliefs are not accepted as valid until they have been carefully tested by experiment and assessed by experts; only then are they allowed publication in the scientific journals, which fulfil the role of the depository of accepted knowledge.

Most scientists would probably agree with this, but my own experience has led me to see it as representing an oversimplified, self-serving position. In theory, scientists are open-minded, but in practice there is a tendency to identify with the official position: ¡°the conclusion that science has come to¡± concerning various things.

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One can list the various ideas that science ¡°knows to be impossible or has shown to be misconceived¡±, including paranormal phenomena, homeopathic medicine and cold fusion. But, on the other hand, scientists ¡°knew¡± that Alfred Wegener¡¯s hypothesis of continental drift was scientifically impossible. The idea was ignored for decades, despite strong evidence in its favour. And an investigating committee of the French Academy ¡°knew¡±, on the basis of too simplified a view of orbits in a gravitational field, that objects could not fall to the earth from outer space. It had to find another explanation for reports of falling meteorites, sometimes still warm to the touch when found. The committee¡¯s explanation was that people had seen a stone being struck by lightning, mistaking the flash for a falling object. The outcome of this application of the scientific method to eyewitness reports was that meteorites were removed from many museums on the grounds that they were of no particular scientific interest. A similar approach, ¡°scientists are right, eyewitnesses are wrong¡±, leads to reports of paranormal occurrences being dismissed in the same way.

We find in Park¡¯s book the official story regarding a number of ¡°mistaken beliefs¡±. What one will not find - and is hard to find anywhere if one does not know where to look to bypass censorship - is the information that might lead one to conclude that the official view does not tell the whole story. Regarding the paranormal, Park follows others in quoting a lecture on ¡°pathological science¡±, given by the noted chemist Irving Langmuir, concerned with claimed phenomena that are difficult to reproduce. In a number of cases, this was because the observed effects were clearly shown to be caused by a flaw and went away when a properly designed experiment was done. But Langmuir then went on to make the dangerous generalisation that if any effect is weak or difficult to reproduce, it is not a real effect. This does not logically follow: an effect may be weak or difficult to reproduce simply because it is weak or difficult to reproduce. It is not easy, for example, to detect neutrinos from the sun, and different laboratories tend to get different results in this research.

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Langmuir considered that the flaw in the telepathy experiments was selective reporting, but present methods address this potential source of error. Park also criticises the use of random-number generators, saying ¡°there are no truly random machines¡±. But parapsychologists today create random numbers using processes that physicists consider random. So if this is the real explanation for apparently successful parapsychology experiments, it would imply that the physicists¡¯ view of the world is also suspect, which would itself be of great interest.

The reader is perhaps beginning to get the general picture. One starts off with an opinion that a belief is wrong and creates an argument to justify this opinion. The arguments spread by word of mouth and are never updated with contrary information that may subsequently arrive, thus becoming the ¡°correct position¡± to take. It is perilous to say anything that indicates doubt about whether this position is in fact correct (though a certain proportion of scientists look more closely and can see the cracks in the official position). This effectively prevents any work in the areas concerned from being published in major journals where it will be seen by others.

Cold fusion - the suggestion that hydrogen nuclei can be made to fuse together and thereby generate considerable energy at near room temperature, using an electrochemical process instead of the usual very high temperatures - was a claim that seemed initially very unlikely to be true, though not totally ruled out. After some workers found themselves unable to reproduce the results initially claimed by Stanley Pons and Martin Fleischmann in 1989, a high degree of scepticism arose in the scientific community, especially after the publication of an official report declaring the absence of any evidence that fusion had taken place.

It is interesting to look both at Park¡¯s account of the history of cold fusion and at that of the protagonists, presented in a video documentary Cold Fusion: Fire from Water (available from ). Park impresses on the reader that if the process that generates the heat is really fusion, one would expect to see fusion products. He fails to mention here, as the video does, that the small amount of such products anticipated, given the amount of energy generated, was eventually observed, and in just the right quantity. All mention of positive results, such as the experiment where, by what appears to be a sound method, it was found that the energy generated was considerably in excess of anything that could be explained conventionally, is collapsed into a paragraph where Park notes that many claims are soon withdrawn because of errors being found (as also happens in ordinary science).

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This device legitimises the dismissal of all positive results, and so also the corollary ¡°cold fusion is no closer to being proven than it was the day when it was announced¡±. This is a seriously misleading statement.

There are scientific arguments against cold fusion, but equally there were arguments against continental drift. The fact that theories have been proposed to provide a mechanism seems not to impress Park as much as the argument made in the video by Douglas Morrison of Cern, the European particle physics society, that one should be ¡°suspicious¡± if one cannot get the same result in an experiment every time. Perhaps he would find such a circumstance less suspicious if he were a materials scientist rather than a high-energy physicist.

Let us move on to another blacklisted topic, the ¡°memory of water¡± (or high-dilution) experiments of French biologist Jacques Benveniste. The claim in this case is that if water is disturbed in certain ways (either by contact with certain molecules or by applying to it an electromagnetic signal) there is some after-effect or ¡°memory¡±, characteristic of the disturbing mechanism, that can be detected for a considerable time afterwards. (In the case where molecules are used, the solution is diluted afterwards to such a degree that only water remains.) This suggestion, like many of the others discussed in the book, seems to arouse irrationally strong reactions from scientists, perhaps because of its associations with homeopathy, also a blacklisted topic. But the objections made appear to be based on bad science. The standard argument is reproduced by Park, who states that a fluid such as water cannot retain any memory over significant periods because the random motions of atoms or molecules will rapidly dissipate any information that might be contained in their arrangement. The argument is invalid because there could be a more global organisation not tied to specific local arrangements and thus undisturbed by local movements of molecules. Something like this happens with liquid helium in its so-called superfluid state, where the background order present in such a state can sustain vortex-like flow patterns that persist despite the continual movements of individual atoms.

As might have been anticipated, Benveniste did not have a smooth ride when he tried to submit a report of his successful experiments to the scientific journal Nature . Neither the editor nor the appointed referees could see any fault with the experiment, but the editor, John (now Sir John) Maddox, imposed a further condition, that Benveniste should allow a team of investigators to go to his laboratory to look for defects in his experiment. Not so extraordinary, except for the fact that the investigation was to follow publication rather than precede it, implying that the object was not simply to prevent incorrect research getting into the literature. Further, the process did not accord with reasonable scientific standards. For a start, the investigative team did not include an active biologist, which one might have considered a reasonable precaution to take to avoid naive errors. Furthermore, it appears that the Nature report was slipped in as editorial comment without being properly refereed. At least, one has to regard it as not being properly refereed because a referee would surely have pointed out that, to justify the title of the report, ¡°High-dilution experiments a delusion¡±, considerably more work would have needed to be done, and in addition that alternatives to the report¡¯s dramatic conclusion had not been properly assessed. In any event, the fruits of this doubtful propaganda exercise became the official conclusion regarding ¡°memory of water¡± research, questioned neither by most scientists, nor by Park.

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Despite its faults, Voodoo Science is an interesting book, with many stories about the kinds of mistakes made by people who believe they have made an important discovery. But it should carry a disclaimer that is the converse of the one with which Park ends his ¡°What¡¯s New¡± column on the American Institute of Physics website: ¡°The opinions in this book are unquestioningly shared by many scientists, but they should not be.¡±

Brian D. Josephson, Nobel laureate, is professor of physics, University of Cambridge.

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