Get your own Free Home Page
Investigations of paranormal phenomena are most often carried out on a case-by-case basis. Investigators go into the field to determine what people actually saw when they saw a UFO. The statistics and methods of parapsychology researchers are examined to make sure that no errors were made. Faith healers are carefully observed to see if anybody is actually cured. The prime rule is: Find out what actually happened and expose what tricks, if any, were used to produce the observed effects. And we are urged to avoid a priori judgements and to keep our minds open to the possibility of the occurence of any kind of an event.
And yet some of us with training in science feel that another approach is legitimate. We should be able to apply to paranormal claims the same methods of deduction that we use in evaluating ordinary physical phenomena. Proper use of previously validated physcial principles should enable us to make educated judgements concerning the plausibility of some of the claims to which we are exposed. After all, one of the things we learn in physics is how to decide between the kinds of actions that may happen in nature and those that are not allowed to happen. These decisions are governed by the fundamental principles of physics. The best-known applications of these principles to the world of pseudoscience is the use of conservation of energy to deny the possibility of a "perpetual motion" device. A small literature exists describing how physics and mathematics may be used to judge the validity of all manner of paradoxical claims (De Morgan [1872] 1915; Ord-Hume 1977; Gardner [1953] 1957; Rothman 1989, 1988).
Invariably, whenever I attempt to explain how knowledge of the laws of physics supports skepticism about reports of UFOs, ESP, astrology, and other such matters, I receive a number of standard responses. These responses demonstrate that much thinking about science has some of the characteristics attributed to mythology. In this article, I would like to show that much of what passes for logical argumentation consists of the repetition of certain cliches that are believed to be true by large numbers of people. These statements are believed to be true because strong psycological forces maintain their presence in human folklore: People want to believe them, and belief in the validity of these ideas provides emotional payoff. Nevertheless, these beliefs have little or no validation in reality. It is for this reason that I call them myths. (The term myth is here used in the sense of "any fictitious story, or unscientific account, theory, belief, etc." [Webster's New World Dictionary 1988].)
1. Nothing is known for sure. This statement represents philosophical skepticism. In addition, the idea that "nothing is known for a certainty" plays a useful political role in the arguments of those espousing one or more paranormal phenomena. If nothing is known for sure, then any one of our present laws of nature may be overturned in the future and replaced by a contrary law. If nothing is known for sure, then it is impossible for scientists to say that a given phenomena is forbidden by nature. If nothing is known for sure, then future advanced civilizations may be able do do all kinds of amazing things that we now consider impossible. Thus the belief that nothing is known for sure is a prior condition for believing in the other myths to follow.
Of course, if we restate the myth as "It is impossible to say that anything is impossible," it becomes transparently clear that a paradox is being perpetrated. Therefore the statement is probably false, a priori.
The philosophical position of skepticism comes down to us from antiquity. It is related to Platonism, which teaches that true reality consists of the thoughts within the mind. It follows that ideas concerning the world outside of our minds are simply constructs manufactured from the raw materials of our individual thoughts. In this kind of universe it is impossible to be certain of anything, not even of our own existence.
Significantly, the growth of modern science has accompanied a move away from Platonism and its replacement by the concept that there does exist a real world outside our bodies and that we all learn about that real world by interpreting signals entering our brains through the channels of our sensory organs. In the realistic philosophy of modern neuroscience there is no seperate "mind" but only the workings of the physical nervous system. All of contemporary science is based on a denial of mind-body dualism.
The fundamental premise of modern science is that there is no doubt concerning my existence and your existence. If we accept the existence of a real universe, then we have made a start toward real knowledge. Either we know something for sure or we know nothing at all.
Bertrand Russell clarified this dilemma when he wrote: "Although every part of what we should like to consider 'knowledge' may be in some degree doubtful, it is clear that some things are almost certain, while others are matters of hazardous conjecture. For a rational man, there is a scale of doubtfulness, from simple logical arithmetic propositions and perceptive judgements, at one end, to such questions as what language the Mycenaeans spoke...at the other" (Russell 1948).
Scientists occassionally err on the side of caution in judging the certainty of their knowledge. In so doing, they feed the myth that "nothing is known for sure." Jacob Bronowski fell into this trap when he said: "There is no absolute knowledge. And those who claim it, whether they are scientists or dogmatists, open the door to tragedy. All information is imperfect. We have to treat it with humility" (Bronowski 1973: 375).
This statement must be understood in its context. Bronowski was speaking of the Heisenberg uncertainty principle: that all physical measurements have a certain degree of error, no matter how carefully the measurement is performed. He was comparing the pragmatic methods of scientists with the dogmatic pseudoscientific theories of the Nazis, whose coming to power in Germany coincided with the development of the uncertainty principle in quantum theory.
And yet, in spite of the undeniable need for care and humility, physicists have learned a great deal during the past century. As a result we can point to some areas of knowledge that possess such a high degree of certainty that it would be folly to deny their validity. A few examples demonstrate the point:
(a) One pluse one equals two. In mathematics this is simply the definition of addition in the domain of real numbers, and within this context it is absolute knowledge. You are free to make other definitions, but then you have a different kind of mathematics (e.g., vector addition). This apparently trivial example demonstrates the importance of definitions in science. While a definition itself may be perfectly and mathematically precise, its application to the physical world depends on the existence and properties of the real objects to which the definition refers. One orange pluse one orange always equals two oranges. However, in physics one kilogram plus one kilogram does not always equal two kilograms.
(b) Another example of the interdependence of definitions and physical reality: all electrons repel each other because (1) they all have negative electric charges and (2) like charges always repel each other. You might say: "How do you know that somewhere in nature there are not a few electrons with positive charges? If they were few enough they might have been overlooked." The answer is that there do, in fact, exist particles that are just like electrons in every respect, but which have positive charges. But these are called positrons rather than electrons. By definition, all electrons have negative charges. Thus, a combination of verbal definition and experiments that demonstrate the existence of these particles gives us knowledge that is quite absolute. There is no uncertainty about the sign of the electron charge because it is a discrete property; the Heisenberg uncertainty does not apply to it.
(c) The earth is not flat. That is, its surface is not a plane surface. This is a negative statement and is qualitative in nature, so its validity does not depend on measurements of the exact shape of the earth. Therefore this statement represents a totally certain piece of knowledge. Similarly, we assert that the earth is not the center of the universe. While at one time saying this may have landed you in the middle of a bonfire, we have, as a result of physical observation, reached the point where this idea is accepted as absolute knowledge.
The statements above do not depend on measurements of absolute precision. Other statments in science do depend on precise measurements, and in those cases we must, indeed, recognize that no measurement is made with complete accuracy. What is not generally appreciated is how very precisely many measurements can be made in physics. The particle model of modern physics has been verified by an interlocking set of measurements whose errors amount to no less than one part of one thousand million. The law of conservation of energy--very important in the evaluation of pseudoscientific and paranormal claims--has been verified by nuclear physics experiments with a precision of one part out of a thousand million milllion (10 [to the fifteenth power]). To get some concept of what this precision means, imagine that you are able to type at the rate of 100 words a minute and that you make only one error out of a thousand million million. This means you can go for 30 million years without making a mistake. This kind of precision can be considered "perfect" for all practical purposes.
What all this means is that the particle model and the law of conservation of energy are pieces of knowledge that possess an extremely high degree of certainty. They are not "just theories." They are part of knowledge. And though they may not be "absolute knowledge" they represent knowledge so well founded that extremely good counter-evidence would be required to jeopardize our confidence in them.
The person who prefaces all arguments with the statement that "we don't know anything for sure" is exhibiting an extreme form of skepticism. His doubt is directed against scientists who claim that psychics cannot fortell the future or that UFOs cannot remain suspended above the earth with no visible means of support. Because the believer in the paranormal wants to believe that nature does allow such phenomena, he often wraps himself in the cloak of an exessively rigorous skepticism directed against scientific knowledge. This form of skepticism is dogmatic skepticism that ignores the empirical knowledge acquired by scientists during the past century.
The scientist, on the other hand, is a pragmatic skeptic. He believes in the importance of looking at physical evidence, and he believes that there is now enough evidence to cast doubt on most paranormal claims, using scientific deduction from validated physical principles. He is willing to change his ideas if sufficient and proper evidence is provided; but when claims are made that require abandonment of the particle model of modern physics or the law of conservation of energy, then he wants to see very strong evidence before he changes his mind.
Understanding the difference between dogmatic skepticism and pragmatic skepticism is of great importance in applying the principles of science to analysis of pseudoscience and the paranormal.
2. Nothing is impossible. If we start with the premise that nothing is known for sure, then it becomes impossible for anyone to say that a proposed action is impossible, for it requires knowledge to make judgements concerning matters of fact. However, if we agree that at least some of our knowledge is certain, or at least verified to a high degree of certainty, then we are in a position to say that some events are not permitted by nature. This is because nature possesses a specific structure characterized by a number of physical symmetries, discovered during the past century, that govern the behavior of all the particles that comprise matter (Rothman 1985). Because of these symmetries, certain actions are allowed to take place in nature and certain other actions are not allowed to take place.
An important symmetry principle (time symmetry) is related to the law of conservation of energy, which--as mentioned earlier--has been verified to an extraordinarly high degree of precision. It is this law that allows us to say with confidence that it is impossible to buiild a device (a perpetual-motion machine) whose operation creates energy out of nothing. It must be emphasized that modern physics gives new meaning to the idea of proving that perpetual-motion machines cannot work. In the past, the method of logical induction required that every possible kind of machine be tested in order to be sure that none of them would work. This would require an indefinite number of tests. Even then you could never be sure, for at any time a different kind of process might come along to allow the creation of energy from nothing. But modern physics finds only four different kinds of energy existing in nature (corresponding to the four forces of particle physics). Thus conservation of energy has only to be tested by showing that in any reaction among any of a relatively small number of particles, interacting by only four kinds of forces, no energy is created or destroyed. Since everything is made of such particles, it follows that conservation of energy is true for all processes in nature. (Under myth no. 4, I will give reasons for thinking that the present four energies are sufficient.)
Conservation of energy applies to more than perpetual-motion machines. It also throws doubt on claims of ESP, precognition, dowsing, and other mainstays of parapsychology. Belief in parapsychology is generally associated with belief in mind-body dualism--the idea that the mind is separate from the body and of a nonphysical nature so that information can enter the mind by some nonphysical means. However, modern neuroscience treats "mind" as something that emerges from the operation of the physical brain. Nowhere do scientists find evidence of psychic energy, spirit, soul, elan vital, or other necessities of mysticism. Therefore all neuroscience starts with a physical model, whose basis is that a number of electrons and ions must be set into motion within the nervous system in order to originate a thought within the brain. Setting electrons and ions into motion requires energy, and this energy must come from somewhere.
When we analyze the situation in detail, we realize that no physical force exists in nature capable of transmitting organized energy (information) from one brain to another without the use of the normal sensory organs. Such a force would have to be capable of working over long distances and be strong enough to move electrons and ions about. The electromagnetic force is the only force in nature with the right properties, but we know that the amount of electromagnetic radiation emitted from the brain is far too small to have the claimed effects. (And radiation from the brain could not explain either direct perception at a distance or precognition.) This evidence makes us highly suspicious of any kind of subjective experience claimed to result from external information stimulating thoughts without passing through the conventional sensory channels.
When one tries to explain why the laws of nature do not allow certain things to happen, enthusiasts of pseudosciences invariably fall back on the argument that "anything is possible." But physics is the science of deciding what is possible and what is not possible, and we now know sufficient physics to make some very reliable decisions.
However, in applying the principles of physics to paranormal phenomena, one must operate with care. It is often difficult or impossible to predict what is going to happen in a given situation, or even to explain what did happen. Our best computers have a hard time prediciting next week's weather. On the other hand, the laws of physics are quite precise in telling in what kind of things cannot happen. Therefore I am on perfectly safe ground when I predict that none of my readers is suddenly going to levitate to the ceiling--no matter what kind of cult he or she may belong to. To make predictions of this sort I rely on what I call "laws of denial"--laws of nature that tell us what is not allowed to happen (Rothman 1988). Conservation of energy and momentum are prime examples of such laws of denial. The principle of relativity, which states that no matter, energy, or information can travel faster than the speed of light, is another law of denial. A judicious use of these laws enables us to judge a wide variety of proposals to be impossible with a very high degree of confidence.
"Anything is possible"--or its equivalent, "Nothing is impossible"--thus turns out to be a myth, useful for agumentation, exhortation, and inspiration. It is expressive of wishful thinking, but based on no foundation of fact.
3. Whatever we think we know now is likely to be overthrown in the future. If we allow that "nothing is known for sure," then all our knowledge has a fluid basis. Nothing has a solid foundation or core. Indeed, there is a psuedo-democratic hint from some quarters that all theories are equal because they are merely matters of opinion, which ignores the empirical basis of scientific theory. This attitude leads to the possibility that whatever we think we know now will be shown to be false and replaced by a new thoery in the future. It is true that many past theories have been replaced by newer theories: The earth-centered solar system was replaced by the sun-centered model; caloric theory was replaced by kinetic theory; ether was replaced by electromagnetic theory; and so on. The resulting feeling of impermanence is often exploited by believers in the paranormal when they say: "Our theories of the mind will change in the future to allow for ESP," or "Relativity will be replaced by a new theory that will allow us to travel faster than light," or "Evolution will be replaced by creationism."
Those who wish to be perceived as knowledgeable sometimes make reference to the work of Thomas Kuhn (1962), who originated the concept of paradigm change. A paradigm is a model of reality whose acceptance by the scientific community is determined by social influences as well as by empirical data. The history of sciecne is a history of changes in paradigms: from Newtonian physics to relativity, from classical mechanics to quantum mechanics. It then becomes tempting to think of all paradigms as subject to change: all theories may be overthrown in the future and replaced by others.
But nowhere in his book does Kuhn say that all paradigms are subject to change. In the past, some false theories have been replaced by correct theories: replacement of the earth-centered solar system by the sun-centered system, for example. The new paradigm is a correct one and will not change in the future. In general, the evolution of theories is from the less correct to the more correct, as instrumentation and experimental methods improve. Often the new paradigm includes the old one as a limiting case. Niels Bohr called this inclusiveness the "correspondence principle," as he showed that quantum physics gives the same results as Newtonian physics when the masses of the objects involved are sufficiently large.
Indeed, since any scientific theory must be based on empirical evidence, it follows that if theory A is able to explain some observations but not others, then when it is replaced by theory B, theory B must explain the same observations as theory A, plus all the others. The new theory must be more inclusive and explain more of the facts than the old theory.
The history of science is much too complex to treat simply as a succession of one theory after another. There are many theories that have not changed since their inception. For example, the concept of energy as a quantitative measure of changes going on in a system has never required a fundamental change, although it has been necessary to add new forms of energy as they have been discovered (and subtract some found unnecessary). The concept that the amount of energy in a closed system never changes has often been challenged, but has never been falisified.
For these reasons I believe it is perpetrating a myth to say that "whatever we think we know now is likely to be overthrown in the future." This is merely a debating device used by those who do not want to admit that physics includes some knowledge of a permament nature.
4. Advanced civilizations of the future will have the use of forces unknown to us at present. When I say that telepathy and other forms of ESP cannot work because there is no force in nature capable of transmitting information directly into the human mind without the intervention of the normal sensory organs, one possible response is that there are forces in nature that we know nothing of but which will be discovered in the future. Similarly, if I say that there are no forces in nature capable of propelling a space vehicle from the earth to Alpha Centauri with a travel time of less than a hundred years, a possible response is that advanced civilizations of the future will have the use of forces we cannot conceive of now.
I think the concept of new and unknown forces is a myth, for several reasons. First, forces do not arise from nothing; nor can human beings generate forces at will. Humans never really "control" nature in the deepest sense of the word. All humans can do is to arrange objects so that when these objects do what they have to do as required by the forces of nature, then the result agrees with our desires. There are four of these natural forces:
- Long-range Strong Electromagnetic
- Long-range Weak Gravitational
- Short-range Strong nuclear
- Short-range Weak nuclear
The two short-range forces operate only at distances of less than the diameter of an atomic nucleus. The strong nuclear force is the most powerful force and is responsible for holding the nuclear particles together. The weak nuclear force is only 10 [to the negative 13th power] as strong and plays a role in the decay of radioactive particles. Because of the short range of these forces they play no role in large-scale affairs, such as setting macroscopic objects into motion and sending messages through space.
The long-range forces operate over large distances (following the inverse-square law), but the gravitational force is so weak that it requires the mass of planets and stars to give effects noticeable without the use of ultrasensitive instruments. It is the electromagnetic force that is responsible for everything that happens on a human level: It holds solids together; it organizes atoms into molecules; it enables us to send pictures through space by electromagnetic waves; it is responsible for all of chemistry and biology.
What of other possible forces? There is no denying the possibility of other forces existing in nature, and physicists are constantly looking for them. For the past several years we have heard many reports of a new kind of gravitational force that either is repulsive in nature or varies with distance differently than the ordinary gravitational force. But this force is exceedingly weak--so weak that all the experiments to date give contrdictory results, making one wonder whether this is another chimerical quest. A force that weak is of no use to us for practical purposes. What we need is a force that is both strong and long-range.
And that leads us to the crucial question: Where is there room in nature for another force that is both strong and long-range? My argument is that if such a force existed it would already have been observed. Remember, forces do not arise out of nothing. They exist as interactions between fundamental particles. But the four known forces are sufficient to explain the bahavior of all the fundamental particles that make up normal matter. To get another force you would need a new class of particles. I will not deny the possibility of creating new types of particles in accelerators at exceedingly high energies, but under ordinary conditions--what physicists call "room conditions--the standard model of particle physics suffices, and in that model the four known forces are considered sufficient to explain all we see.
Since the human brain consists of ordinary matter, there is no possibility of explaining the phenomena claimed by parapsychology with the aid of new and unknown forces. As for the possibility of creating extraordinary matter capable of generating extraordinary strong and long-range forces for propulsion of interstellar vehicles, even the extraordinary energy generators of black holes emit no detectable radiation outside the description of the standard model. If unexpected forms of matter or energy do exist, they apparently do not interact with standard matter and so are useless for practical purposes.
5. Advanced civilizations on other planets will possess great forces unavailable to us on Earth. The UFO as portrayed by modern mythology is a saucer-shaped object that hangs high in the air unsupported by any visible means. There are no forces known in nature that can hold such a large mass motionless high in the air. Some UFO enthusiasts claim the trick is done by magnetic fields. However, we know a great deal about magnetic fields, and such a feat of levitation cannot be performed by such means. A magnet needs another magnet to push against in order to levitate (and fields strong enough to do the job would be detectable all over the country). Rockets won't supply sufficient force for more than a few minutes. What else is left? The answer always given at this point is: Advanced civilizations on other planets possess great forces unknown to us on Earth.
The response to such a statement is essentially the same as that given for myth No. 4. There are only four different forces in existence, and of these only the electromagnetic force has the range and strength to do useful work for humans. And this force is unable to hold a massive vehicle suspended in midair without a visible light and sound show. There is no reason to believe that planets orbiting distant stars have other kinds of forces, because when we analyze the light coming from those distant stars we find that all the stars contain the same kinds of matter and the same kinds of energy as our own solar system. Things are not different in other parts of the universe. In fact, this statement of uniformity is the central premise of modern cosmology. If the entire universe started from one big bang and spread out from that initial mass, then matter everywhere must be the same, for it all comes from the same source. There is no way for other parts of the universe to be made of different kinds of matter with properties radically different from our own.
Epilogue
Myths are rarely countered by facts. Once born, they carry on independent lives. But it is necessary to be aware of them if we are to maintain a realistic view of the universe. Knowledge of the laws of physics--especially the conservation laws--helps us make decisions about the borderline between myth and fact, between fantasy and reality.
References
Bronowski, J. 1973. The Ascent of Man. Boston: Little, Brown.
De Morgan, A. 1915. A Budget of Paradoxes, 2nd ed. Chicago: Open Court.
Gardner, M. 1957. Fads and Fallacies in the Name of Science. New York: Dover. First published by G. P. Putnam in 1953.
Kuhn, T. S. 1962. The Structure of Scientific Revolution. Chicago: University of Chicago Press.
Ord-Hume, A. W. J. G. 1977. Perpetual Motion. New York: St. Martin's Press.
Rothman, M. A. 1985. Conservation laws and symmetry. In The Encyclopedia of Physics, 3rd ed., ed. by Robert M. Besancon. New York: Van Nostrand Reinhold.
--------. 1988. A Physicists's Gude to Skepticism. Buffalo, N.Y.: Prometheus Books.
--------. 1989. Discovering the Natural Laws. New York: Dover. First published by Doubleday in 1972.
Russell, B. 1948. Human Knowledge, Its Scope and Limits. New York: Siimon & Schuster.
Webster's New World Dictionary. 1988. Third College Edition. New York: Simon & Schuster.
[This article is from The Skeptical Inquirer, Vol. 14, No. 1, Fall 1989]
Get your own Free Home Page