My first suggestion to you is this: do not accept what you see. Let me explain.

Arthur Ellison is Professor of Electrical Engineering at the City University of London. Not only is he an excellent scientist, but he possesses a resolute sense of humour. He has been interested in the paranormal for most of his life, and he recently gave a lecture on the subject to a mixed audience of scientists and non-scientists. Towards the end of his talk, he asked the audience to participate in an experiment.

Next to him on the rostrum was a bowl of flowers on a table. Much to the dismay of the audience, he asked them to concentrate collectively on the bowl of flowers to see whether they could levitate it. With some pitying smiles and anxious frowns, the audience eventually began to concentrate. The professor said that to help them he was going to play a tape-recording of the Buddhist chant 'ommm', a sound which is supposed to make the whole universe change.

The concentration of the audience grew deeper, the lecture hall was pervaded with the ominous droning sound of the chant. Slowly at first, gradually more rapidly, the bowl of flowers began to wobble, and finally it left the surface of the table and floated clear, several millimetres in the air. Levitation!

The audience drew back aghast at their achievement. Without warning, the bowl of flowers crashed down to the table; immediately the audience broke up in a furious buzz of conversation. What had happened?

The point of my story is not the levitation, but that two people came up to Professor Ellison afterwards. One was an old lady, the other a professor of physics.

The old lady said, 'Do you know, Professor, when the bowl of flowers lifted I saw a grey substance between the bowl and the table and between the legs of the table and the floor.'

The professor of physics snorted derisively. 'I don't know what all the fuss was about, nothing moved at all!'

Actually, the bowl of flowers did move and did levitate, because the professor had hidden special magnets in the bowl and under the table. He had played the Buddhist chant of 'ommm' to hide the humming noise of the electromagnets. However, and this is really what assessing the paranormal is about, the old lady saw a grey substance, but there was no grey substance; the professor saw nothing move, when something did move. The vision of both lady and professor was completely faulty.

Lord Reith was once accused of employing biased broadcasters in the BBC. His reply was: 'I am glad to be able to tell you that none of my broadcasters is free of bias.'

In the field of the paranormal there has been more irrational bias and more furious, vindictive and downright nasty criticism than in any other field of scientific investigation. Scientists, clerics, writers and mystics have all pitched in with a ferocity which would do credit to a street gang and which has nothing at all to do with science, reason or evidence. Why?

If, as I now accept, there is something there in the paranormal, it is potentially the most important and optimistic development in the whole field of human knowledge. Instead of having to accept the view that we are just fleshly beings in a materialistic and mechanical universe, the paranormal allows us, if it is valid, to accept, as reasonable beings, that there is much more to the human mind, the human condition and the universe around us.

This view threatens a lot of people who defend a particular view of things. It upsets the vested interest of some clerics who hold to a dogmatic theological standpoint; it upsets some scientists who wish to preserve a mechanistic picture of the universe; it upsets some writers who prefer an unshakeably sceptical position, because it means that they do not have to try to extend their view of things, and can remain in the relatively comfortable role of permanently Doubting Thomases. There are, fortunately, just as many clerics, scientists and writers who do preserve critical but properly open minds.

There are three main ways of acquiring knowledge: by direct experience, by reason, and by authority. I will deal with the first two later, but it is knowledge by authority that the paranormal threatens. Knowledge by authority is no more than, 'I say it is so, my own colleagues agree that it is so, and so it is so.' A good example of this way to knowledge was told to me by a professor of physics in Vienna.

When the idea of meteorites arriving on the earth from space was first suggested, it was clearly impossible, because the planets had been found to move in regular ellipses: nothing broke out of a regular ellipse. A statement was put out by the ruling scientists: 'Anyone who holds the irrational view that meteorites originate in space shall suffer expulsion from our learned society of astronomers.'

Later, when the evidence for the actual, extra-terrestrial origin of meteorites had become completely overwhelming, a statement was again put out: 'Anyone who holds to the irrational view that meteorites originate on earth shall suffer expulsion from our learned society of astronomers.' No one blushed. Most thinkers want to belong to a club of like thinkers; it feels cosy.

My suggestion is that you should adopt the view of Groucho Marx, who remarked: 'Any club who would have me as a member, I wouldn't want to belong to.' Think for yourself, do not join a club. What can you think, what can you believe? The Oxford Dictionary defines 'believe' as 'have faith in ...' or 'accept the truth of . . .'. If someone says 'there is a God', that is a statement of belief. If another says 'there is no God', that is also a statement of belief, because both people have faith in what they said. Neither statement is susceptible to analysis, measurement or solution.

To take a simpler example, if someone says, 'I believe I can predict the future,' that is a belief which can be examined and checked. If a large number of people claimed (as they did) that they predicted the sinking of the Titanic, then these claims alone are no more than statements of belief: 'I believe I predicted the sinking of the Titanic.'

If, on the other hand, you were an author called Morgan Robertson who wrote a novel some twelve years before the Titanic actually went down, in which you imagined a fictional liner called the Titan sinking, your novel might have achieved decent obscurity unless you also described the following points about your fictional liner which were nearly the same for the Titanic:

We are now in a much better position to interpret the statement 'I believe Morgan Robertson predicted the sinking of the Titanic some twelve years before it actually did sink.' The novel was a matter of documentary record in 1898, the year of publication. Did Morgan Robertson predict the future?

When scientists look for similarities between pairs of events and things, they talk about 'correlations' between them. This is really no more than saying that they are looking at the patterns of similarity between them. Looking at the similarities between the fictional SS Titan and the real life SS Titanic, there are a large number of correlations by any standards. We can begin to suspect that Morgan Robertson actually did predict the sinking of a liner twelve years before it happened. But did he?

We can now ask more useful questions. Were the details of the Titanic design known in 1895, when the novel was being written? They were not in fact, but there are other questions which help us to evaluate the extremely odd correlations. Were there general principles of ship design around at the time which might have enabled the author to make a fairly detailed guess as to its design? Yes, there were; but were these detailed enough to get that number of correlations? I don't think they were, but others disagree. The mythological name Titan has often been used for describing something large, so this could have also been coincidence. But was it? The number of lifeboats per ton weight might also have been a fixed relationship agreed among ship designers and so the author could have been almost right on this score, just by researching his book carefully.

What seems at first sight to be a clearly paranormal prediction now begins to come under question, but the questions do not invalidate the possibility that Morgan Robertson did in fact see a future event before it happened; they simply stop us rushing in and making too many assumptions. If you would like to study the Titanic story in more detail, there are more detailed accounts to be studied. [1, 2, 3]

What the questions achieve is that they force us to make ground rules for the evaluation of reports like this, so that anything we do finally accept as paranormal is likely to be as a result of a stringent application of reason and analysis.

G. W. Lambert, in the Journal of the Society of Psychical Research [4], suggested that when studying a prediction:

1 The prediction should be reported to a credible witness before the event to which it appears to relate.

2 The time interval between the prediction and the event should be short.

3 The connection between the person making the prediction and the prediction itself should be improbable.

4 The prediction should be described literally and not symbolically.

5 The details of the prediction should tally with the details of the event.

Next time a friend tells you that they dreamt about an air crash and an air crash occurs shortly after the dream, ask these questions and see how accurately predictive the dream really was. Even when the questions have been asked though, there will always be an element of uncertainty. Just how good were the correlations between prediction and event? The 'how' is one of the great problems associated with claims in the paranormal.

If your friend predicts an air crash and one occurs shortly afterwards this is not especially interesting by itself, because a future air crash is a near certainty, and people often dream about things that frighten them, like air travel. But if they get the time, the aircraft type, the flight number and the casualties all correct, or partly correct, within the rules I have suggested, then it is reasonable to assume a connection between the mind of the dreamer and a future event. There are many such accounts in the literature referred to above. [1, 2, 3]

The doubt always remains, however, with anecdotal evidence. Can investigators do better? Yes, because they can design and perform experiments. What is an experiment, and what constitutes a good or bad experiment?

An experiment is a test of an idea, where the outcome of the test is not known. A good experiment is a test where all possible ways of explaining the idea have been looked for and one is selected as true and to be tested, and where all the methods used are fully declared for other people to assess and to repeat.

A bad experiment is a test where these conditions have not been met and where doubts and loopholes remain unanswered or undeclared. For example, returning to the metal-bending example I used in the introduction, if an investigator is taken into a room where a subject is sitting holding a teaspoon which he is stroking and the teaspoon bends downwards and the bowl drops off the handle as he strokes it, this is a thoroughly bad experiment because the subject could have used a special teaspoon (as I did in the television programme) or he could have almost broken it secretly by hand and then completed the break when he stroked it.

A good experiment would be as follows: a teaspoon is bought in a shop by the investigator; it is carefully examined by a metallurgist and marked, then presented to the subject under the continuous view of the investigator and a number of disinterested observers and kept in continuous view by the investigator and observers as the subject attempts to bend it, ideally under filmed conditions. If at the end of the experiment, the spoon has bent, or broken, it is returned under continuous observation to the metallurgist. If both investigator and observers are satisfied from their observations and subsequent study of the film that the subject could not have bent the spoon with his fingers, then it would be reasonable to say either that the subject bent the spoon paranormally, or that there was collusion or fraud between investigator and subject, or between investigator, subject and observers.

If the subject can repeat the bending and the investigator writes up his experiment in sufficient detail for the other people to repeat it exactly, then paranormal metal bending could be said to be proved beyond reasonable doubt.

There are, as I shall show, an increasing number of very cautious investigators who are examining paranormal metal bending under conditions as tight or tighter than those I have already suggested.

But what about collusion and fraud? Does it occur? Yes, it does, I am afraid - but not only in the field of the paranormal. It also occurs in ordinary laboratories and among ordinary jobbing Scientists. J. B. Rhine, one of the founders of experiments into the paranormal, found thirteen clear cases of cheating, [5] and others have since come to light. Yet in 1976 Ian St James Roberts conducted a survey of cheating among ordinary scientists. [61 To the great surprise of both academics and other professionals, a substantial proportion of scientists, it was found, knew of at least one colleague who had consciously or unconsciously fiddled his results.

I can remember filling in the questionnaire the study was based on. One question was effectively: have you ever spotted a scientist cheating? I wrote: 'Yes'. The colleague whom I had seen cheating did so on such a massive and unlikely scale that first of all I simply could not believe it, but it was true nevertheless. He is now a senior professor. He was certainly deluding himself, but I am not exactly sure to this day whether he was deliberately deluding others as well. His basic problem was an absolutely compulsive personal ambition.

There is one striking difference between cheating in ordinary science and cheating among experimenters on the paranormal. In ordinary science, as St James Roberts points out, 80 per cent of those caught cheating received no public punishment and some continued to be promoted. But where experimenters on the paranormal are concerned, all thirteen were cut out of the field of research altogether and their work publicly registered as dubious unless it could be repeated. An excellent review of cheating in science and the paranormal is to be found in the work of an experimental psychologist Dr Charles Tart. [7]

There clearly has been cheating in experiments on the paranormal. This has been used by a number of people as a total explanation of all paranormal phenomena. This is a perfectly legitimate point of view, but it is one which is rarely applied to ordinary scientific research and which has now been carried to a quite unreasonable extreme.

One critic began his examination of the paranormal with the statement: 'In view of the a priori arguments against it, we know in advance that telepathy etc. cannot occur.'[8] Another referee for an article on the paranormal submitted to a scientific journal said, 'This is the kind of thing that I would not believe in even if it existed.'[9]

A conjurer … has issued a challenge, promising 10, 000 dollars to anyone who can: '. . . demonstrate any paranormal ability under satisfactory observing conditions.' I wrote to him asking for his conditions and, having studied them, I am persuaded that no one can possibly adhere to the conditions he lays down under any experimental circumstances whatever.

There is also a Committee for the Scientific Investigation of Claims of the Paranormal which performs the valuable function of doubting all claims to paranormal effect. Such criticism, when detailed, particular, and properly analytical, is an essential part of the search for reliable data, but unfortunately this committee has also repeatedly spilled over into rhetoric, invective and nonspecific generalities and has entirely spoiled its reputation among ordinary scientists by failing to get to grips with the mass of experimental data which is publicly available.

On the reverse side of the coin there is a very large number of completely gullible people in the field who accept absolutely everything they hear about the paranormal, from sharpening razor blades under pyramids to UFOs from Atlantis.

Both sides of this polemic and unreasonable divide have no place at all in any rational assessment of the paranormal, and can be safely ignored.

We now need to examine another feature of the world about us before arming ourselves with the means to judge claims in the paranormal. Two words are important - 'luck' and 'chance'. 'Luck' means nothing more than good fortune, and yet it is often used about people. A punter is said to be lucky if he wins regularly at the races, but the word itself has no explanatory meaning. It doesn't tell us how or why he wins.

'Chance', on the other hand, is more useful. If I toss a coin, then, after a large number of tries, I will find that it comes down 50 per cent heads and 50 per cent tails. Supposing I then ask someone to guess whether the coin will land heads or tails while the coin is still in the air; that someone is normally going to be right by chance 50 per cent of the time. Therefore if they make 100 guesses, they should be right 50 times by chance.

If another person, say, gets 61 guesses right, that is well above chance and would only happen once in 100 guesses, so you can say that the odds against getting 61 right by chance are 99 to 1 against. There is a fixed mathematical relationship between the number of correct guesses in a run and the odds of that number occurring by chance. If someone regularly got this sort of score under the sort of experimental conditions I have outlined then it would be reasonable to search for a cause.

For example, it would be entirely reasonable to investigate the possibility that the subject was either 'seeing' into the immediate future of the coin or influencing the coin directly with his mind that is, if he had not substituted an artificially loaded coin. This is why I am going to move next onto the story of the new physics. To see into the future or to influence metal with the mind is by the rules and standards of the old physics absolutely impossible. It simply cannot happen, and yet it is the firmly held view of many of the world's most able physicists that such connections are possible. So, I am going to look at some of the changes in physics which have created this complete revolution in ideas about how the universe works and how the mind can connect with matter.