Hardly anyone who witnesses this performance and is not an expert magician can see through it. To the uninitiated it looks like good solid scientific evidence for telepathy. The essential clue, which almost everyone misses, is the address book that Broch glances at before writing down the name of the accomplice. The address book contains a list of the fifty-three cards in a standard deck, each paired with a common French first name. The accomplice has another copy of the same list. As soon as the accomplice hears the name, he knows the card.
The book also has a good chapter on “Amazing Coincidences.” These are strange events which appear to give evidence of supernatural influences operating in everyday life. They are not the result of deliberate fraud or trickery, but only of the laws of probability. The paradoxical feature of the laws of probability is that they make unlikely events happen unexpectedly often. A simple way to state the paradox is Littlewood’s law of miracles. John Littlewood was a famous mathematician who was teaching at Cambridge University when I was a student. Being a professional mathematician, he defined miracles precisely before stating his law about them. He defined a miracle as an event that has special significance when it occurs, but occurs with a probability of one in a million. This definition agrees with our commonsense understanding of the word “miracle.”
Littlewood’s law of miracles states that in the course of any normal person’s life, miracles happen at a rate of roughly one per month. The proof of the law is simple. During the time that we are awake and actively engaged in living our lives, roughly for eight hours each day, we see and hear things happening at a rate of about one per second. So the total number of events that happen to us is about 30,000 per day, or about a million per month. With few exceptions, these events are not miracles because they are insignificant. The chance of a miracle is about one per million events. Therefore we should expect about one miracle to happen, on the average, every month. Broch tells stories of some amazing coincidences that happened to him and his friends, all of them easily explained as consequences of Littlewood’s law.
A large number of people calling themselves parapsychologists have tried to study paranormal phenomena using rigorous scientific methods. Their favorite tool is a little deck of twenty-five cards, with one of five symbols on each card. The five symbols are squares, circles, stars, crosses, and squiggles. An ideal telepathy experiment is done with two people, the sender and the receiver, sitting in separate rooms, with careful controls to eliminate all possibility of communication between the two of them or between them and the experimenter. The sender and the receiver synchronize their activities with accurate clocks. At fixed times agreed in advance, the sender picks cards from a well-shuffled deck, gazes at them one at a time, and records the sequence of cards gazed at. At the same times, the receiver guesses the cards and records the sequence of guesses. At the end of the experiment, an impartial witness, not the experimenter, compares the two records and finds the percentage of correct guesses. If telepathy is not operating, the percentage should be close to twenty. If the percentage is persistently higher than twenty, the experimenter may claim to have found evidence for telepathy.
If this idealized picture of a telepathy experiment were real, we should long ago have been able to decide whether telepathy exists or not. In the real world, the way such experiments are done is very different, as I know from personal experience. When I was a teenager long ago, parapsychology was fashionable. I bought a deck of parapsychology cards and did card-guessing experiments with my friends. We spent long hours, taking turns at gazing and guessing cards. Unlike Broch, we were strongly motivated to find positive evidence of telepathy. We considered it likely that telepathy existed and we wanted to prove ourselves to be telepathically gifted. When we started our sessions, we achieved some spectacularly high percentages of correct guesses. Then, as time went on, the percentages declined toward twenty and our enthusiasm dwindled. After a few months of sporadic efforts, we put the cards away and forgot about them.
Looking back on our experience with the cards, we came to understand that there are three formidable obstacles to any scientific study of telepathy. The first obstacle is boredom. The experiments are insufferably boring. In the end we gave up because we could not stand the boredom of sitting and guessing cards for hours on end. The second obstacle is inadequate controls. We never even tried to impose rigorous controls on communication between sender and receiver. Without such controls, our results were scientifically worthless. But any serious system of controls, stopping us from chatting and joking while we were gazing and guessing, would have made the experiments even more insufferably boring.
The third obstacle is biased sampling. The results of such experiments depend crucially on when you decide to stop. If you decide to stop after the initial spectacularly high percentages, the results are strongly positive. If you decide to stop when you are almost dying of boredom, the results are strongly negative. The only way to obtain unbiased results is to decide in advance when to stop, and this we had not done. We were not disciplined enough to make a decision in advance to do 10,000 guesses and then stop, regardless of the percentage of correct guesses that we might have achieved. We did not succeed in overcoming a single one of the three obstacles. To reach any scientifically credible conclusions, we would have needed to overcome all three.
The history of the card-guessing experiments, carried out initially by Joseph Rhine at Duke University and later by many other groups following Rhine’s methods, is a sorry story. A number of experiments that claimed positive results were later proved to be fraudulent. Those that were not fraudulent were plagued by the same three obstacles that frustrated our efforts. It is difficult, expensive, and tedious to impose controls rigorous enough to eliminate the possibility of fraud. And even after such controls have been imposed, the conclusions of a series of experiments can be strongly biased by selective reporting of the results. Littlewood’s law applies to experimental results as well as to the events of daily life. A session with a noticeably high percentage of correct guesses is a miracle according to Littlewood’s definition. If a large number of experiments are done by various groups under various conditions, miracles will occasionally occur. If miracles are selectively reported, they are experimentally indistinguishable from real occurrences of telepathy.
Charpak and Broch see the modern growth of astrology and other pseudosciences as a rising menace that they are called upon to fight to the death. They are horrified by the prevalence of unscientific thinking among students in France today. They sum up their response to these irrationalities in another elegant Gallic sentence: “The question is inescapable: Isn’t scientific thought the indispensable companion to wisdom, to clear thinking, and to the love of those virtues, which is expressed not only in vain incantations to the sky but also in logical actions?” They have here touched on a question which goes to the heart of the matter. What are the proper limits of science?
There are two extreme points of view concerning the role of science in human understanding. At one extreme is the reductionist view, holding that all kinds of knowledge, from physics and chemistry to psychology and philosophy and sociology and history and ethics and religion, can be reduced to science. Whatever cannot be reduced to science is not knowledge. The reductionist view was forcibly expressed by Edward Wilson in his 1998 book Consilience. At the other extreme is the traditional view, that knowledge comes from many independent sources, and science is only one of them. Knowledge of good and evil, knowledge of grace and beauty, knowledge of ethical and artistic values, knowledge of human nature derived from history and literature or from intimate acquaintance with family and friends, knowledge of the nature of things derived from meditation or from religion, all are sources of knowledge that stand side by side with science, parts of a human heritage that is older than science and perhaps more enduring. Most people hold views intermediate between the two extremes. Charpak and Broch are close to the reductionist extreme, while I am close to the traditional extreme.
The question of the proper limits of science has a strong connection with the possible existence of paranormal phenomena. Charpak and Broch and I agree that attempts to study extrasensory perception and telepathy using the methods of science have failed. Charpak and Broch say that since extrasensory perception and telepathy cannot be studied scientifically, they do not exist. Their conclusion is clear and logical, but I do not accept it because I am not a reductionist. I claim that paranormal phenomena may really exist but may not be accessible to scientific investigation. This is a hypothesis. I am not saying that it is true, only that it is tenable, and to my mind plausible.
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 firsthand 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 suggesting that paranormal mental abilities and scientific method may be complementary. The word “complementary” is a technical term introduced into physics by Niels Bohr. It means that two descriptions of nature may both be valid but cannot be observed simultaneously. The classic example of complementarity is the dual nature of light. In one experiment light is seen to behave as a continuous wave, in another experiment it behaves as a swarm of particles, but we cannot see the wave and the particles in the same experiment. Complementarity in physics is an established fact. The extension of the idea of complementarity to mental phenomena is pure speculation. But I find it plausible that a world of mental phenomena should exist, too fluid and evanescent to be grasped with the cumbersome tools of science.
I should here declare my personal interest in the matter. One of my grandmothers was a notorious and successful faith healer. One of my cousins was for many years the editor of the Journal of the Society for Psychical Research. Both these ladies were well educated, highly intelligent, and fervent believers in paranormal phenomena. They may have been deluded, but neither of them was a fool. Their beliefs were based on personal experience and careful scrutiny of evidence. Nothing that they believed was incompatible with science.
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. I recommend this book to believers and skeptics alike. It is good entertainment, whether or not you believe in astrology.
Postscript, 2006
A deluge of eloquent letters came in response to this review. Orthodox scientists were outraged because I considered the existence of telepathy to be possible. True believers in telepathy were outraged because I considered its existence to be unproved. This is a question that is of deep concern to many readers. The most interesting response came from Rupert Sheldrake, who sent me papers describing his experiments studying telepathy in dogs. Dogs have several advantages over humans as experimental subjects. They do not get bored, they do not cheat, and they do not have any interest in the outcome of the experiment. Sheldrake’s experiments contradict my statement that telepathy cannot be studied scientifically. Unfortunately, the experiments were conducted by humans, not by dogs, and effects of human bias and selective reporting could not be altogether eliminated. But Sheldrake is right when he says that the experiments are scientific. They are repeatable, and ought to be repeated by independent investigators using different dogs. Interested readers may examine the evidence in Sheldrake’s book, Dogs That Know When Their Owners Are Coming Home, and Other Unexplained Powers of Animals (Crown, 1999), and in his more recently published papers.
1. Georges Charpak and Henri Broch, Debunked! ESP, Telekinesis, and Other Pseudoscience, translated from the French by Bart K. Holland (Johns Hopkins University Press, 2004).
2. Paris: Éditions Odile Jacob, 2002.
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MANY WORLDS
LIFE SOMETIMES IMITATES art. Olaf Stapledon wrote Star Maker sixty-six years ago as a dramatization of a philosophical idea. Now, sixty-six years later, cosmologists are proposing similar scenarios as possible models of the universe we live in.
Stapledon was a philosopher and not a scientist. He wrote this book to explore an elegant new solution of the old philosophical problem of evil. The problem is to reconcile the existence of evil in our world with the existence of an omnipotent and not entirely malevolent creator. The solution is to suppose that our universe is only one of many, that the creator is engaged in creating a long series of universes, that he is improving his designs as he goes along, that our universe is one of his early flawed creations, and that the evils that we see around us are flaws from which the creator will learn how to do the job better next time. Stapledon brings the story to a climax in his penultimate chapter, “The Maker and His Works,” which paints a powerful picture of the creator as a craftsman using us as raw material to practice his skills. The hero of the story is a human observer, who first explores the multitude of worlds in our universe on which intelligent life has evolved, and then finally confronts the Star Maker. But that supreme moment of confrontation is tragic rather than harmonious. Like God answering Job out of the whirlwind, the Star Maker strikes him down and rejects him. The Star Maker judges his creation with love but without mercy. In the end, our entire universe, in spite of all its majesty and beauty, is a flawed experiment. The Star Maker is already busy with designs for other universes in which our flaws may be repaired.
Within the last few years, Lee Smolin and Martin Rees and other cosmologists have been addressing a very different philosophical problem. They are not concerned with moral judgments but with scientific facts. It is a scientific fact that our universe is strangely hospitable to the growth of life and intelligence. Many details of the laws of physics and chemistry seem to conspire to make our universe friendly to life. If the details of nuclear forces, gravitational forces, and chemical forces had been slightly different, life as we know it could never have evolved. Our form of life was able to adapt itself to the universe in which it originated, but there is no way in which any form of life could have adapted itself to a universe that collapsed into a fiery space-time singularity before it had time to give birth to stars and planets, or to a universe that expanded into a cold dilute gas before giving birth to any atoms heavier than hydrogen. It seems that our universe is somehow fine-tuned, with the forces of gravitational collapse and cosmic expansion almost exactly balanced, so that stars and planets have time to evolve, and the atoms of the various chemical elements necessary for life have time to be formed. The philosophical problem of explaining why the universe is hospitable to life is called the fine-tuning problem.
Lee Smolin was the first cosmologist to point out that the fine-tuning problem is solved if we assume that our universe is one of many, that new universes sprout like babies within older
universes, that babies resemble their parents, that baby universes are born with a random assortment of laws of physics and chemistry, and that longer-lived universes give birth to more numerous babies. When these assumptions are made, it follows that a process of Darwinian evolution will select longer-lived universes. And it is no accident that creatures like us happen to live in one of the longer-lived universes that has laws of physics and chemistry fine-tuned to the growth of life and intelligence. Among the billions of universes that exist, only a few will be fine-tuned enough for life to evolve, and one of those few must be our home. Smolin’s many-universe cosmology does not require a Star Maker to design it. It only needs the hidden hand of natural selection to guide its evolution, and the luck of a favorable random variation to provide a home for life.
The astronomer Martin Rees has suggested another way in which nature might have solved the fine-tuning problem. He remarks that if a multitude of universes exists, then some of them are likely to allow the evolution of life-forms with mental processes far more advanced than ours. A superintelligent life-form might be capable of simulating in its brain or in a supercomputer the complete history of another universe with a lower degree of complexity. Now Rees asks the question: Might we and the universe we live in be simulations, lacking any real physical substance and only existing as mental constructions in the minds of our superintelligent colleagues? “This concept,” says Rees, “opens up the possibility of a new kind of virtual time travel, because the advanced beings creating the simulation can, in effect, rerun the past. It’s not a time-loop in a traditional sense: it’s a reconstruction of the past, allowing advanced beings to explore their history.” Rees solves the fine-tuning problem by allowing future superintelligent beings to fine-tune the past.
The Scientist as Rebel Page 32
