"Quantum Physics and Reality"
by Ronald C. Pine

The 20th century is a remarkable story of technological achievement. Within a few decades, electricity, radio and TV, not to mention lasers, fiber optics, plastics and computers, have all become an everyday facet of our lives. I take for granted that I can turn on a TV set in Hawaii and receive, almost instantaneously, a program that originated in Atlanta or New York. Only a short time ago exchanging information between New York and Hawaii required the same time it takes to send a spacecraft to Mars today. Except for power failures, few people in the developed world know what it was like for most of the human species every night, throughout 99 percent of our history, to face the blackness of space and its sea of stars alone without the reassuring lights of civilization. We live in a special time. Never before has such intense, radical technological change taken place. In this chapter we will see that there has been another radical change: Something very strange has happened to reality along the way.

What Is an Electron?

Our story will begin here because it is the electron, and our knowledge of it, that has been responsible for so much of the technology that we take for granted today. Without the electron there would be no electricity, no electric lights, no TV and no radio. We would not have supermarket doors that open automatically or computers to play video games and do word processing and spreadsheets for business. But what exactly is an electron? In the early moments of the 20th century, scientists found themselves asking this very question. The discovery of radiation and the atom promised to open up a strange new world of knowledge, understanding and power.

At first physicists assumed that the atom was like a miniature solar system. At the center was a nucleus consisting of particles glued together somehow, and circling this nucleus were the swiftly moving electrons, like little particle planets. This model did not last long. Although we still use a version of this model today to have some visual handle on what the atom looks like, scientists discovered fairly quickly that mathematical calculations based on this model predicted that the electron would crash into the nucleus in an instant.

Physicists also discovered that electrons could be stripped from the atoms and made into beams of radiation. This was a great breakthrough, because scientists could manipulate these beams and being to deduce from the beams' behavior the nature of the electron itself. A similar channel of investigation was taking place in attempting to understand the nature of light. From this, another remarkable discovery was made: beams of electrons behave very much like beams of light!

We saw in our study of Relativity that the speed of light was considered a paradox at the turn of the century. By this time the nature of light was also highly controversial and something of a paradox. Under some conditions light seemed to behave as if it consisted of very small particles of matter (now called photons). Under othe conditions, however, light showed clear signs of being a wave of energy, a disturbance of a medium, the intensity of which could be measured. To understand how this is a problem, we must first clearly understand that a particle and a wave are very different phenomena.

A particle is a piece of matter, like a baseball, that at any given time has a definite size, speed and location. It can only be in one place at a time. A baseball thrown in Hawaii cannot be in New York at the same time. Furthermore, we assume that we may discover in this marvelous universe some very strange objects, but regardless of how strange they are, if they are objects, then they will have a definite location at any given definite time. Any object such as a baseball cannot be in two places at the same time.

A wave, on the other hand, is a very different kind of thing. In fact, it is appropriate not to refer to it as a thing at all, but rather as an event or phenomenon. Things by definition have a definite localized size at a given definite time. Waves do not. Imagine dropping a pebble into a still pond of water. At first there is a small splash, and then circular waves move away from the spot where we dropped the pebble. The wave spreads out; it does not stay in one place, but it can be in many places at the same time. Also, it is the medium of the water that transmits the energy of the dropped pebble. The wave is simply a disturbance of the medium. It does not have an existence of its own like the smile of the Cheshire cat in "Alice in Wonderland". Without the water in the pond, there would be no waves.

On the north shore of the island of Oahu in the State of Hawaii, every winter large waves pound the shoreline. These waves are caused by the seasonal winter storms migrating northeast of the state in the jet stream on their way to make life miserable for people in the Pacific Northwest and eventually much of the rest of the United States. The winds from the migrating storms cause a significant disturbance in the sea and a series of undulations or transmitted many miles until finally, reaching the reef on the north shore of Oahu, spectacular waves of 20 feet or higher break and push forward a mountain of water and foam toward the beach. On the cliffs overlooking Waimea Bay you can watch a gigantic half circle of water march relentlessly toward the beach and then simultaneously, across a quarter mile area, surge onto the beach. It is a spectacular sight. Tourists travel many thousands of miles to see it, and single-minded surfers wait in anticipation all year, hoping to be the first to ride the biggest wave on record and survive.

It would be a strange event indeed if one day, while watching wave after wave break, we saw one wave flow in its normal way toward the beach and then, just as the wave was about to touch the first fingers of vulnerable sand, the entire half circle of water collapsed instantly to a single unpredictable point on the beach and exploded! The wave would have turned into a massive particle located at one place, rather than spread out as waves normally are. Imagine wave after wave doing this, with the location of the collapse being unpredictable each time. Strange indeed this would be, but something like this is what electrons and photons seem to do!

Thought Experiments

The science of the subatomic realm is called quantum physics or quantum mechanics. The word "quantum" refers to the fact that energy at the microscopic realm comes in packets, or quanta; energy is said to be "discrete" rather than continuous. The best way of understanding the implications of discrete motion is to understand the most famous phrase in this science, the "quantum jump". As we will soon see, this does not refer to a continuous, quick motion of an object, but rather a discontinuous, instantaneous movement from one place to another. In orders words, quantum objects seem to be able to move from place to place without being anywhere in between. They seem to "pop" in and out of existence.

In the following pages, we are going to retrace the same baffling steps that physicists have taken in the past 70 years. Their goal was simply to understand the nature of subatomic objects such as the electron and the photon. The result was a revolution in thought so radical that even Einstein could not accept it. But we will be using a method Einstein would have approved of, what are called "thought experiments". Instead of looking at the actual technical experiments (in most cases), we will imagine a series of composite pictures that remain true to the actual experimental findings. Technically, these are known as the Photoelectric effect, Compton effect, Young and Davisson-Germer diffraction wave experiments, Stern-Gerlach interferometer experiments, Bell's inequality theorem, and the Aspect experiments.

Imagine first a lead box impenetrable except for two microscopic slits on one side. On the inside of the box on the side opposite the slits is a photographic film. Imagine that on the outside facing the two slits we have a source of radiation, beams of electrons or light, and that we aim this radiation at the face of the box with the two slits. By looking at the kind of exposure that results on the photographic film, we can deduce what kind of radiation is penetrating the box. For instance, if the radiation consists of beams of particles, then only those particles that happen to be aligned with the two slits will pass through into the box , and the result should be a "particle effect". The photographic film should show a diffused piling up of little hits adjacent to the two slits.

On the other hand, if radiation is a wave, then a much different effect should result. We should see a "wave effect", roughly what we would see if we dropped two stones in the water at the same time. Two circular undulations would collide into each other and interfere with each other. In our example, a wave would split in two as it enters the two slits, and then the two new waves would begin to spread out again, eventually colliding with each other as in our pond example. This should cause an "interference effect", a wave picture, on the photographic film. Instead of a piling effect adjacent to the two slits, the radiation would spread throughout the length of the photographic film, producing alternating bands of exposure. Some of the wave crests would meet and accentuate each other, and some would meet the troughs of other waves and cancel each other. The exposed bands on the photographic film would be the result of the crests meeting.

When similar experiments are done, the result is remarkable. The photographic film always shows an interference effect indicating a wave (see the figure part a). Unfortunately, the radiation produces this same effect in passing through a vacuum. How can a wave exist without a medium to disturb? Also, when we look closely at the exposure of the film, the exposed areas show piles of little hits, as if millions of particles hit the film, each blackening only a single grain of film in unpredictable locations (d). Remember that if radiation is a wave, then as it reaches the film, it should be spread out along the entire length of the film like a wave breaking in a beach. But how can it hit at only one unpredictable place? This is as ridiculous as the possibility of watching a wave move toward a beach and seeing the entire wave collapse at a single point on the beach!

Obviously, more experiments are necessary. Baffling results are common in science. So let's close one of the slits and see what happens. Perhaps the particles are so small that as they penetrate the slits they ricochet all over the interior of the chamber, bouncing off each other in a wild, unpredictable manner that eventually produces the illusion of an interference effect. After all, the electron is about 10,000 times smaller in mass than an average atom. Thus, in closing one of the slits, we would lessen this wild ricocheting, and a piling effect should result adjacent to the single slit. Sometimes, nature cooperates. If we alternate opening and closing each slit, then the result appears to be consistent with the particle hypothesis--a double-piling effect adjacent to each slit (b).

But wait. To be sure that we are dealing with a particle, let's return to our original setup with two slits open simultaneously. This time, however, we will lower the intensity of the radiation. In other words, another way to lessen the possibility of the ricocheting effect, and at the same time rule out the wave hypothesis is to filter the radiation to such a point that only a single "measure" of radiation passes through into the chamber at a time. If we assume that the radiation consists of particles, then if only a single particle is passing through at a time, it can go through only one slit or the other. If it is a particle, then it cannot be in two places at the same time and thus will not ricochet off of other particles or itself.

Conducting this experiment will take a long time for an exposure to develop because millions of particle hits will be required to make an exposure, and each particle has three choices: to penetrate the chamber through either of the two slits or be repulsed by the lead barrier. Nevertheless, we should eventually observer a particle effect--a double-piling effect of hits adjacent to the two slits, as in (b).

Alas, nature fails to cooperate. The result is an interference effect, exactly as in (a) and (d)! Now we are really in trouble. Why should we get a wave effect with two slits open, even though the exposure is the result of two unpredictable hits, and a particle effect with only one slit open? With two slits open the radiation is acting as though it penetrates the chamber at two places simultaneously (then it interferes with itself), something only a wave can do. With one slit, however, the radiation is more localized, as we would expect from particles, which can only be in one place at a time.

It is easy for the beginner to lose sight of the philosophical significance of these results. Many of the great names of science, however, who were working at this baffling microscopic realm, also had a background in philosophy, and it was immediately apparent to them that there was something major at stake here. Since the time of the ancient Greeks and the fledgling beginnings of scientific exploration, we have assumed that we are dealing with one world, one consistent reality. That is, even though we expect the world to be baffling at times, with strange and new details of discoveries, we also expect that whatever these details are, they stay the same independent of our knowing. They are "out there" waiting for us to discover, and they are what they are regardless of our knowledge or ignorance.

We assume as Newton did that the world does not depend on us or how we choose to make our observations of it. We do not expect something to be a particle on Mondays, Wednesdays, Fridays and Sundays and a wave on Tuesdays, Thursdays and Saturdays--especially when these phenomena are entirely different types of phenomena. What kind of a world would it be for us if dogs were dogs on Mondays but turned into cats on Tuesdays? It would surely make dealing with the world and taking care of pets very difficult.

Because this notion is so important, let's try one more example. What we want to know is, does the radiation pass through both open slits simultaneously or only through one? Consider then the following experimental arrangement: both slits open, one measure of radiation entering the chamber at a time, but with an added feature--a detection device inside the chamber that will reveal whether or not the radiation is passing through both slits as a wave or only one or the other of the slits as a particle would (c). Because the situation is almost identical to the case in which an interference effect was recorded (a), we would expect to see the detection device react as though a wave were surging through both opening simultaneously. On the other hand, if the radiation consists of particles, then only one instance of detection should be recorded at a time. Remarkably, the latter is the case--only one instance of detection is recorded at a time--and the photographic result is now consistent with the arrangement of only one slit or the other being open, as in (b)!!

As physicists in this century conducted further experiments with subatomic phenomena, they found that all subatomic phenomena display the same ambiguity, which has come to be known as wave-particle duality . This ambiguity was not easy to accept. One of the most fundamental principles of science seemed to be mocked by these results: the notion that we are dealing with, and can know the details of, the objective world. It is perhaps one of the greatest achievements of this century that in spite of this shock, a very successful mathematics was developed that not only allowed physicists to predict the results of the above experiments but also produced one of the greatest scientific and technological success stories in recorded history. In 1926 the physicist Erwin Schrodinger gave us the Schrodinger wave equation, and the science of physics has never been quite the same. The equation "explains" the preceding results but with a high "price" to be exacted from our own common-sense view of the world.

As we would expect from the name, the equation literally portrays the radiation as a wave, but a very strange wave. According to the equation, in our two-slits-open configuration as soon as the radiation leaves its preparation point, it begins to spread out in a strange multidimensional "hyperspace". As it encounters the slits it splits, as any real wave would, passing into the chamber and interfering with itself. Remember, this is one indivisible unit of radiation! As the radiation touches the photographic film, however, it regains its physical indivisibility by collapsing to a single unpredictable point! We can never predict at what point the radiation will be received, but we can always, with a remarkable consistency, predict the probability of where it will strike and the overall statistical pattern, not only for this particular arrangement but for all the others as well.

Few physicists, however, accept this literal interpretation; most have been taught to think of the equation as a calculation device. The special mathematical function used is thought to represent only a "probability function"--that is, given initial conditions, the probability of finding a hit, or a pattern of hits, at a particular location. Thus, the only waves the exist are said to be "probability waves".

But wait. What happened to reality? What is a probability wave? What is an electron? What is a photon? Are these questions no longer meaningful? Let's look at one more example...

When such an experiment is actually conducted, it is a relatively simple matter to show that one whole unit of energy is detected at either A or B, confirming again that we are dealing with a single object, a little thing that can be at only one place at a time. If a photon is a particle, then it will pass through the mirror and be detected at A or be reflected and detected at B. However, the Schrodinger equation is a wave equation. Although we must be careful using such language, according to this equation, the half-silvered mirror splits a wave packet into two "hyperspatial, virtual/real, probability" waves.

At the exact moment that the energy reaches the detectors, some sort of strange decision is made, and the entire unit of energy is received at only one point, at either A or B! The wave packet collapses. If a whole unit is received at A, then the energy that was approaching B has jumped over to A. In addition, the equation predicts this will happen even if the two detectors are separated by many light-years, even if one detector is much closer to the half-silvered mirror than the other. The latter case implies that the energy approaches A and either jumps to A or the energy that was approaching A goes "backward in time" and collapses at B. The mathematics always works, but what it describes literally seems impossible. Like Alice in Wonderland, we cannot believe in impossible things...can we? So physicists explain that we must not think of the split wave packets as real, but only as a description of the probability of where photons will go.

But wait. Now comes the crucial question. Does the light really pass through both channels? Quantum jumping aside, we can at least test for the radiation passing through both channels. Consider the following arrangement (lower half of the figure). This time we will create an interferometer by placing totally reflecting mirrors at the points where detectors A and B were. Thus, if the light beam is really split by the half-silvered mirror, the totally reflecting mirrors will now reflect the split beams of light. If we aim these totally reflecting mirrors so that the beams will meet again, then we can take a picture of the waves interfering with each other, just as we did in the two-slit experiment. With this arrangement, interference fringes result similar to that found in the two-slit experiment. The interference effect can be produced by having one of the totally reflecting mirrors slightly farther away than the other, so that the light waves will arrive out of phase. The beams are recombined by another half-silvered mirror and transmitted to a chamber with a photographic plate.

If the intensity of the light is reduced to one photon at a time, then the interference effect can only be accounted for by assuming that the photon really splits into two wave packets and then recombines. In fact, if we pick up an ordinary playing card and block one of the paths, there is no interference picture. Instead, a diffused piling exposure is created, similar to the particle picture we received when only one slit was open. If the radiation is a wave, then we can understand the interference picture. If the radiation is a particle, then we can understand the fact that only one detector at a time receives one whole unit of energy. The result of one arrangement indicates that a wave of some kind is really passing through both channels simultaneously. The result of the other makes sense, if we assume that the radiation is passing through only one channel at a time. If the radiation is passing through both channels at the same time, why do the detectors not trigger simultaneously? How does the radiation passing through one channel get over to the other detector? How could this possibly happen if the detectors are far enough away that any transmission of a signal between them would require a speed greater than the speed of light? It's time for a little philosophy.

The Copenhagen Interpretation

Nature at the subatomic level apparently does not conform to normal logic. Either light is a particle or it is not a particle. Either light is a wave or it is not a wave. Either the light splits and goes through both channels or it does not. If it goes through both channels, then it should be detected in both channels. It is not detected in both channels, yet it does go through both channels. If it goes through both channels, why is only one unit of energy detected at one detector? How do two halves spatially separated become one whole unit instantaneously?

There is no logical inconsistency within the mathematics that explains the phenomena. In the particle effect case, the mathematics allows us to predict that approximately 50 percent of the time detector A will record a unit of energy and 50 percent of the time detector B will record a unit of energy. In the interferometer arrangement, the mathematics predicts an interference effect and even allows a straightforward calculation of the wave length of light by measuring the interference fringes. The problem is more in our reaction to the results of these experiments and the success of the mathematics. We want to know what kind of a "thing" is producing these results. What is going on out there that enables the mathematics to be successful? Our minds desire a complete understanding. What is real? What is the truth?

These questions reflect our natural tendency to want to go deeper, to find the basic, hidden causes of all things. Western civilization and its science since the ancient Greeks has assumed that the cosmos consists of one distinct, complete reality full of details. We have also assumed that the details, whatever they might be, can be known, and knowing these details does not affect what the details actually are independent of the knower. This is consistent with our common sense and what each of us experiences every day: a world undisturbed by human thoughts, wishes, and desires...full of things, spatially separated from each other, and interacting with each other through distinct recognizable forces. If someone has a tangerine tree in his yard, he might wish that it were an apple tree, but it will still be a tangerine tree. Similarly, we do not think of someone thinking cancer into existence or wishing it away. We think of the cancer being "out there", something beyond our mental control, like trees. We can cut down trees and operate on cancer, but they are distinct realities that we "discover" with our thinking, not something that we "create" with our thinking.

So it is natural for us to think of the electron as an independent thing. It shows signs of being a particle, so we begin to think of it as if it is really a particle independent of our observations of it. But it also shows signs of being a wave, and it cannot be both a wave and a particle at the same time, no more than a tree can be both a tangerine and apple tree at the same time.

In the 1920s, a few philosophically minded physicists, led by the Nobel-Prize-winning physicist Niels Bohr, realized that nature was trying to tell us something very important. Once again nature was using paradox to convey a fundamental error in the assumptions we were making and the way we were asking our questions. According to Bohr, and what is known as the Copenhagen Interpretation (so-called because much of the work was done in Copenhagen, Denmark), descriptions such as "particle", "wave", "position" and "mass" are human concepts. These concepts involving assumptions of space and time work for us at a normal macroscopic level and will always be indispensible for describing the results of our physical experiments. But nature is now making it clear to us that we have reached a barrier in our attempt to describe it in terms of human concepts derived from ordinary experience.

Wave-particle duality is nature's way of informing us that we have no right to impose our human concepts on the subatomic level. Just as Einstein had discovered that we have no right to impose our normal assumptions of space and time to all levels of reality, so quantum physics reveals that we have no right to impose our most basic thoughts about the nature of reality on the subatomic realm. The idea of an extended thing sitting in a three-dimensional space, waiting for us to discover it, is revealed as another human projection, a limited image of reality, more of an echo of the way our minds work than of reality itself. According to Bohr, nature reveals this to us by showing that we can have only complementary views of reality. If we set up an experimental arrangement to view subatomic phenomena as particles, then that is what we will observe. According to Heisenberg, another major contributor to the Copenhagen Interpretation, what we observe in our experiments is not nature itself but nature exposed to our methods of questioning nature. In short, an electron is not a thing until we observe it!

A Debate: Bohr versus Einstein

Ironically, the main resistance to the Copenhagen Interpretation came from Albert Einstein and a few of his followers. Einstein objected very much to the idea that we had stumbled upon a barrier to knowing what is real. Philosophically, Einstein was a realist who believed that the goal of science was to conjecture boldly about the nature of reality from the details of our observations. He acknolwedged that as we continue to probe nature for her secrets, we would encounter more and more exotic features, most of which we could never directly observe because of the nature of our observational limitations. He believed, however, that the human mind could always fathom at least the most likely hypothesis about the nature of the reality causing the events we do observe. Thus, although Einstein introduced a revolutionary view of space and time, one that destroyed the classical or Newtonian conceptions of absolute space and time, he nevertheless remained a classical physicist faithful to the concept of reality. Descartes stated centuries earlier: "There is nothing so far removed from us to be beyond our reach or so hidden that we cannot discover it."

For Einstein, nature was like a mysterious clock. We are limited to observing only the exterior features of this clock. We may never be able to see directly inside and know for ceratin how the clock works, but by observing and thinking about the movement of the hands long enough, the human mind will provide a likely answer to how the clock works. For Einstein, a clockwork for the universe exists and can be known. For Bohr, to assume that a clockwork exists independent of our observations is only another human philsophical bias, another example in a long line of assumptions that experience validates at a certain level, but that experience at another level now demonstrates cannot be considered "the way things are".

If an electron is not a thing until it is observed by some instrument, does this not imply that reality depends on our observations and hence, ultimately, the thoughts we use to frame the world? Does this not imply that reality is created by human thoughts? Metaphysical idealism is an old and widespread belief stating that the physical world as we experience it is basically an illusion; the perception of a world of material things separated in space is said to be only an appearance. Individual things exist only insofar as we have an idea of them. If there were no human observer or recording instrument of any kind in a forest, then a falling tree would make no sound. In fact, there would be no tree to fall and no forest. When I walk out of a room, I assume that the physical room and all its contents are still there. But according to the idealist, the room ceases to exist if no one is there to have a thought of the room.

Most scientists have always viewed this metaphysics with disdain, as more of a symptom of despair of the sometimes harsh realities of the physical world, as primarily a religious view associated with those who find the physical universe threatening and who desire a more perfect but duller world. Does quantum physics validate the philosophy of idealism? How embarrassing for Western science if it does. Imagine that after thousands of years of struggling to know the details of the atom, Western science shipwrecks into a religious philosophy it thought it had left behind at a more primitive time!

Thus, Einstein viewed quantum physics as an incomplete theory: We simply do not know enough yet. Because we cannot produce a consistent picture of subatomic phenomena, we obviously do not know exactly what these things are yet or enough about the mysterious forces governing their motions and manifestations. "God does not play dice with the universe", according to Einstein. He has created one universe and does not choose to have it manifest itself as waves one moment and as particles at another for no reason.

Bohr and Einstein had several public debates over what was the proper interpretation of quantum physics. These were fascinating discussions between two intellectual giants, but little was resolved at the time. The vast majority of physicists heeded Bohr's advice that there was a pragmatic limitation inherent in our measuring devices. Physicists should be interested primarily in being able to predict experimental results and not in the question of what is real. They were persuaded that the question of what is real is primarily an unanswerable philosophical question. Physics must concern itself primarily with complex experimental arrangements and the derivation of the complex mathematical formuale needed to predict events. On the other hand, motivated by the goal of finding a hidden reality, physicists have also pursued Einstein's dream of a unified picture of reality, of seeking a theory that enables us to understand at a fundamental level the mysterious forces of nature.

Physics is still proceeding in two, perhaps complementary, perhaps schizophrenic, directions--one following Einstein's dream and the other developing a series of experiments to confirm Bohr's theory of complementarity. Using a particle approach and a model of subatomic objects consisting of different types of quarks, many physicists have become confident that they are approaching an understanding of the basic clockwork of the universe. These physicists believe that what appear at a certain level to be different forces in nature are actually different manifestations of a superforce, a force that existed for only a brief moment under the superhot, superenergetic conditions of the first microseconds of the universe.

Because of the present relatively mild conditions of the universe, this force is hidden from us, and because it is hidden we are left with the many paradoxical results of quantum appearances. Thus, throughout the world the race is on, with billions of dollars being spent, to set up the wild conditions that will, it is thought, finally coax nature into revealing her true self. And there are those who, like Paul Davies in his book "Superforce", have declared confidently, not unlike Helmholtz did for Newtonian physics, "that for the first time in history we have within our grasp a complete scientific theory of the whole universe in which no physical object or system lies outside a small set of basic scientific principles".

Bell's Discovery

But does nature have a "true" self? Following Bohr, experiments have been conducted that are consistent with the view that it does not, that in our relationshiop with the universe we can have only different pictures of the clockwork--actually, to be more precise, that a precise clockwork does not exist until we attempt to picture it! For many years, following the Bohr-Einstein debates it was thought that the issue between them must forever be relegated to the realm of inconclusive philosophical perspectives. No one knew of a conceivable experiment that could disconfirm either one. Bohr could argue that the present experimental data are most consistent with his theory of complementarity, but he could not prove that some day we would not discover some bizarre "hidden" reality that explained how an electron could manifest itself as a wave in one situation and a particle in another. Similarly, the followers of Einstein could argue that if we think, and search, long enough, someday we will find this hidden reality. No one though an experiment could be devised that would eliminate the possibility of a hidden reality.

In 1964 physicist John Bell discovered that it was theoretically possible to test whether or not quantum physics was a complete theory. By tinkering with the mathematics, he discovered that an experiment could be devised to confirm or disconfirm hidden processes, or "variables" as physicists refer to them.

Before we describe this discovery and its application in crucial experiments, let us review first why quantum measurements are so puzzling. The essence of all the puzzles, according to the physicist Henry Stapp, is "How do energy and information get around so fast?" In the interferometer experiment we can demonstrate that a wave is passing through both channels. But when we modify the experiment to detect the radiation in each channel, we detect only one whole unit of energy at a time per channel, implying not only that the radiation consists of particles, and therefore not waves, but also that the radiation is not in both channels.

In the particle detection experiment the Schrodinger equation describes a wave-splitting process with a "probability" wave in both channels and then an instantaneous collapse of a potential existence to one localized "actual" spot, to either detector A or B. The Copenhagen Interpretation deals with this puzzle by claiming it is inappropriate to think of radiation as some kind of real thing before we measure it. The radiation "becomes" something only after we measure it. It is always a particle after we measure it, even though some measurements suggest the particle has wavelike properties between measurements. Reality, specific attributes possessed by things, according to the Copenhagen Interpretation, can only be discussed in terms of an "entire experimental arrangement".

According to Bohr, the problem of quantum measurement does not necessarily imply an idealist metaphysics. Concepts such as "particle" and "wave" are human concepts, and we have discovered that nature will not allow us to picture it consistently with these concepts. Insofar as we must always conduct our experiments through a human framework, with human concepts, there is an epistemological barrier that no future scientific discovery will change. For Bohr, the success of quantum theory represents a "treasure chest" of scientific and philosophical discoveries. The Copenhagen Interpretation should not be viewed as advocating a dogmatic end to reserach and discovery but rather a dramatic discovery that continues a trend first started by Copernicus and sustained most recently by the startling discoveries of Einstein: The universe is not required to conform to human concepts.

In a fundamental way Bell's discovery allowed physicists to test Bohr's claimed epistemological discovery. We could now see whether or not the subatomic realm had a true self independent of our measurements.

Quantum Jogging

Because the actual experiments and Bell's discovery are somewhat complex, let us try an analogy first. Suppose we have a large group of runners. Half of the runners are tall and half are short. Suppose that each of the short runners and each of the tall runners has a twin. Each of the twins will begin running at the same point, but in the opposite direction to a finish line that is the same distance from the original point of departure. Suppose also that each runner will run the course at the same speed, and that the spacing between the times when each runner leaves is such that no runner will be able to overtake the runner immediately preceding him. No tall runners will overtake short runners or vice versa.

Imagine then a continuous stream of runners leaving the original point and running in opposite directions. We might have something like this: Two short runners leave the starting point one after the other simultaneous with their respective twins, then two tall, then two short again, then one tall, and one short after that, then two tall, and so on. Suppose that the overall pattern is random. Suppose further that the contingencies of the course and physical training of each runner are such that many of the runners will not finish. Suppose also that each twin has a very strong desire to finish, such that any one twin will want to finish if and only if the other twin finishes.

Now we are ready to carry out the implications of our thought experiment. In spite of the strong desire of each twin to finish if and only if the other does, our common sense would predict that finishing together is not likely. Suppose one of the short runners pulls a muscle just before the finish line. How likely would it be that the twin, running on an independent track, separated by a considerable distance, either knows this and decides to stop running or pulls a muscle and also does not finish? In other words, if we were to observe the runners finishing and established a mathematical correlation of completion, we would not expect it to be very high. Suppose that about 90 percent of the tall and short runners did not finish; it would not be likely that every time a short or tall runner finished or did not finish, the respective twin finished or did not finish as well. If we found the random result at one finish like to be T, T, S, T, S, S, T, S, we would not expect this result to be highly correlated or equal to the result at the other finish line. We would expect an inequality in the results.

There is one possibility, however, where the results could be highly correlated. Suppose each runner carried an electronic beeper, such that whenever a runner knew he could not finish, he would signal the twin not to finish. In other words, if the runners could communicate, a very high correlation could be established.

Suppose though that we change our thought experiment a little. This time we will control, at one finish line, which runners finish and which ones do not. Suppose at a point immediately before one of the finish lines we set up a fork in the course, such that the short runners must take one path and the tall runners must take the other. Suppose further that we have control over an electronic switch that closes the path by throwing up a barrier for either the short or tall runners. By randomly changing the switch we can change which path is open and which type of runner finishes. It is important to be able to do this after the runners have already left. Otherwise the runners could know ahead of time what kind of course they must run and adjust their actions accordingly. Suppose that the barriers are so close to the finish line, and we are able to switch the barriers so rapidly, that there is no time for each twin to signal the other whether he is going to finish or not. Now clearly there could not possibly be a very high correlation. It would be a strange result, indeed, if even most of the time when a tall runner finished, his twin also finished, and most of the time when one did not, his twin did not, and likewise for the short runners.

We assume that the locla conditions at a barrier cannot instantaneously influence the local conditions at the other finish line. This locality assumption is an inherent part of our normal view of reality. We assume that the runners are independent individuals who will face independent conditions at independent places. What Bell showed is that if this assumption is correct and also applies to the subatomic realm, then the results we obtain in the subatomic realm with particles should reflect the same kind of inequality in correlation we expect to find in our macroscopic realm of short and tall runners.

Quantum theory, on the other hand, predicts an entirely different situation for subatomic particles. Because it is incorrect to refer to subatomic particles as having any definite state with a definite place until a measurement takes place, an analogous runner's example to what happens in the subatomic realm would be the following: Our runners do not exist as definite runners until they are observed to finish, and a measurement at one finish line will instantaneously produce a correlated set of characteristics at the other finish line! From a quantum perspective, the locality assumption is denied; it is incorrect to think of our runners as real independent entities, in real independent places, experiencing real, local, independent circumstances. Instead, between the time we see them leave and finish, our runners are a "superposition of states" of existence. They are neither tall, nor short, nor fast nor slow, but all these potential states at once.

If quantum theory is true, then an analogous experiment in the subatomic realm should result in a significant violation of Bell's inequality deduction because it is incorrect to think of subatomic particles as independent things with definite properties until a measurement takes place. If experiments are devised where "twin" particles are created and fly off in opposite directions like our runners, then quantum theory predicts that there will be a high correlation of the particle states when they are measured at a quantum finish line because a measurement of one particle instantaneously collapses a wave function of potential states, a wave function that was created at the time of the twin particle creation.

The Aspect Experiment

Perhaps because the locality assumption is so obvious, or perhaps because the technological tools were not sufficiently developed to conduct the proper experiments, or both, recognition of the significance of Bell's work was slow in coming. A decade after Bell published his work, intense discussion and experimental work finally began. The most recent experimental results, based on a design that physicists acknowledged ahead of time would be the crucial experiment, show decisively that in the subatomic realm Bell's inequality is violated and the predictions of quantum theory are correct. The results show that the measurement of a subatomic particle at one finish line instantaneously determines the state of its twin at another finish line, regardless of how far apart the two finish lines are.

In the realm of subatomic particles, our runners are replaced by mathematical objects with attributes such as "charge", "spin", "velocity" and "momentum". We naturally tend to think of these attributes in the same way we think of the attributes of our runners. Just as we think of each runner as a real, independent body with definite characteristics such as being short or tall, fast or slow, we are more comfortable thinking of a particle having a real location or a real spin. Quantum physics, however, seldom allows us to be comfortable. Consider quantum spin. What kind of real attribute requires a subatomic particle to turn around twice before it shows its original face?! Imagine looking at a position on the Earth from the Moon, say New York, and watching the Earth spin around twice before New York is visible again.

As bizarre as these quantum attributes are, quantum physicists have learned how to deal with them mathematically and even set up experiments that create twin particles with opposite spin. The most recent, and most conclusive, we will call the Aspect experiment (after the French physicist Alain Aspect, who was the leader of a team that conducted this crucial experiment. The results were published in an unassuming three-page paper "Experimental Tests of Realistic Local Theories via Bell's Theorem", Physics Review Letters, Aug 17, 1981). Using polarization, a property that can be thought of as similar to spin ("polarized" sunglasses only allow photons of light through with particular spin orientations, thus selectively lessening the intensity of light that passes through), physicists tested Bell's inequality prediction. Atoms were excited to produce twin photons of light that sped away with opposite polarization. Methods were developed to test the states of the photons at their respective finish lines. In many respects this experiment was analagous to our thought experiment with the barriers and the electronic switch.

Bell's inequality theorem was violated: The spins of particles at distant finish lines were highly correlated. Because there was an analagous switching device (activated by high-frequency waves at a rate of 100 million times per second...the finish lines were 10 meters apart), there was no possibility that a signal could be sent (at the speed of light) between the two devices for photons crossing the "finish lines" to communicate, thus enabling their spins to be correlated through conventional means (so they must have been correlated through some strange quantum effect). In summary, the result was as fantastic as our hypothetical, unlikely thought experiment concerning runners, that most of the time a tall runner finishes or does not finish, so does the twin, and the same is true for short runners. There is now little doubt that a violation of Bell's inequality is a fact of life. If there is a "hidden reality" with forces influencing the results of our paradoxical measurements, these forces must travel faster than the speed of light. They must be instantaneous.

Note that the violation of Bell's inequality is a "factual" demonstration that at least one assumption of Einstein's realism must be false, what we referred to earlier as the locality assumption. To accept the totality of Einstein's realism, we must assume that the local conditions at one finish line could influence the local conditions at the other finish line only if the two locations are linked by a causal chain whose transmission of effects does not exceed the speed of light. In other words, if reality consists of separate objects, then one object cannot influence another object unless some sort of signal or influence travels from one object to the other during some amount of time. If the movement of one object "instantaneously" influences the movement of another object, then they are not really separate objects.

Recall from Chapter 7 that some very strange results are possible if the speed of light can be exceeded. Our mother astronaut could return to Earth and be involved in a fatal automobile accident before her child was conceived and before leaving for her space voyage. Thus, for many reasons, a hidden force traveling faster than the speed of light is ruled out as a possible explanation for the puzzling results of quantum experiments. The Aspect experiment shows that we must reject the totality of Einstein's realism, but not necessarily all possible versions of realism. The entire universe at the subatomic level could be one object.

The results of the Aspect experiment and the violation of Bell's inequality are also consistent with the Copenhagen interpretation: Quantum objects should not be considered things until a measurement takes place. Unfortunately, the implications of this interpretation for the nature of reality are philosophically disturbing for most physicists when they bother to think about them. Thus, most physicists ignore the pragmatic aspect of the Copenhagen interpretation and ignore the reality question. The reality question is something for "the philosophers" to worry about. This response is often portrayed as a sophisticated, modern point of view: physics should not be concerned with futile philsophical questions, but keep to the business of predicting results and applying quantum mathematics to novel situations such as computer technology, fiber optics, chemistry, and even biology. By any standard this approach has been very successful. However, is this instrumentalist approach any different from the reaction of past scientists to Ptolemy's epicycles, Copernicus' circles around invisible points or Newton's gravity?

Quantum Ignorance and Reality

For many, the reality question beckons still. The history of physics, and science in general, shows that the traditional pursuit of "the way things really are" is not just an ivory tower game. A quest for a deep understanding has been valuable not only for its own sake but for the purpose of maximum practical application as well. The history of science has demonstrated repeatedly that when we understand the way things are at an invisible level, we are better able to understand, control, and predict the visible world in which we live. Until quantum physics, the vast span of scientific endeavor had vindicated Einstein's simple vision: The better we have been able to understand the invisible mechanism of the cosmic clock, the better we have been able to understand the motions of its visible hands. We may not be able to see Kepler's ellipses or Newton's gravity in the starry night, but an understanding of these veiled realities has enabled us to embrace the night sky-to predict, to control, to see, to explore-in a manner undreamt of by the ancients so patiently and relentlessly watched this surface reality. Other examples abound: The understanding of the molecular and atomic constitution of matter has enabled us to deal with the surface experiences of heat, temperature and pressure; by understanding a deeper level of reality, we have been able to create objects that do not exist in nature, such as plastics; and now, by understanding the invisible structure of DNA, we are close to controlling the development of life itself, with many practical applications in agriculture and medicine.

Is it over? The Copenhagen interpretation implies a strange kind of ignorance-call it quantum ignorance. According to Bohr, it is a mistake to search for a hidden, deeper mechanism that will explian the results of quantum measurements, because between measurements there is nothing there to know, that is, nothing there can be conceptualized in human terms. This is nature's way of educating us, of revealing its ultimate message: "Picture me with your human pictures if you must, but do not take your pictures too seriously."

For those sympathetic with Einstein, there must be something more; the results of quantum experiments must be only an example of what can be called classical ignorance. There must be something there that we are "disturbing" when we interact with it in attempting to measure it. We are ignorant of why quantum events happen as they do only because we do not know all the forces acting on subatomic particles, just as we cannot predict each throw of the dice in a dice game, because there are too many minute factors involved and any attempt on our part to measure these minute factors in the act would disturb the results. In the case of dice there are other ways of demonstrating the existence of these factors, and thus we have every reason to believe that they are there, even if we cannot control them.

Bell's theorem and the consequent experiments do not rule out some kind of realism, that some kind of hidden force or reality is at work in the subatomic realm. The do demonstrate, however, that these forces, if they exist, must be very strange forces. Unlike any previously discovered forces, they must be capable of propagating instantaneously regardless of distance. If our finish lines for subatomic particles were billions of miles away, then the violation of inequality would be the same. If one of our finish lines were located in the vicinity of the star Betelgeuse, 540 light-years distant, and the other on Earth, then quantum physics predicts that there would be no difference in the results. The results of Bell's theorem and the Aspect experiment show not only that quantum theory is a complete theory but also that any interpretation of quantum physics must incorporate the fact of instantaneous action.

Newtonianism implies that what is real does not depend on us, and reality is reducible to small independent particles of physical matter and empty space; thoughts, ideas, colors, emotions are all considered to be secondary realities, not real, but rather the result of the movement and interactions of particles. This view is seriously contradicted by the science of the 20th century, particularly by the Copenhagen interpretation. What is real does seem to depend on us and our method of questioning nature. As the physicist E. P. Wigner has claimed, a measurement cannot legitimately be said to have taken place until it is acknowledged by the conscious awareness of a human being. Far from being a secondary reality, consciousness has a much greater significance in quantum theory. We confront the world with the filters of our human thoughts about the world, and nature conforms to these thoughts to some extent. A reality becomes manifest based upon the thoughts behind one of our experiments. We do not measure reality as Newton and all classical physicists believed; we measure the "relationship" between reality and our thoughts.

In the quantum realm we cannot pin down a consistent reality, and nature teaches us in the process not to take our thoughts about reality too seriously, on the one hand, and to take them very seriously, on the other hand. We should not think of our human concepts of "particle" and "wave" as reflecting an independent reality, but we have been forced to recognize the creative power of human concepts. The mathematics of quantum theory pictures not a precise clock with definite parts but a strange indefinite cosmic substance capable of manifesting an infinite number of fleeting faces. Quantum theory pictures the particles that make up everything that we touch and feel not as little, hard, definite, independent things, but as a tangle of possibilities entangled with every other tangle of possibilities throughout the universe. As with the particles in the Aspect experiment, the particles in my body may be connected in some way with the particles of your body, and these in turn with particles in a distant sun, in a distant galaxy, billions of light-years away.

Neorealism

The results of relativity and quantum theory have sent physicists and philosophers of science scurrying in many different philosophical directions. Although most physicists have accepted the practical dictates of the Copenhagen interpreation, David Bohm, among others, has refused to abandon entirely the realism of Einstein, opting instead for a radical neorealism. For Bohm, the Aspect experiment does not disprove a "hidden" reality but only one that consists of separate things. A universe of "undivided wholeness" is consistent with all the experimental results. A real universe exists independent of our observations of it, but it is not like the room that I am in now: a bowl of space with apparently independent objects separated into different locations. "Underneath", so to speak, from a perspective of a multidimensional hyperspace or superspace, this appearance of separateness can be seen to melt like ink dots in water.

Mathematical equations that literally describe a hyperspace, a multi-dimensional space, which scientists often cryptically refer to as "configuration" or "phase" space, are common in the mathematics of modern physics. As we have noted, most physicists have been taught during their university educations to think of these as only mathematical devices because it makes no sense to use ordinary language or pictures in an attempt to ascribe a reality to such bizarre number juggling. Bohm, however, following the lead of Einstein, suggests that what works in our equations may point to an underlying reality.

Consider the following analogy from Bohm's "Wholeness and the Implicate Order". Imagine a fishbowl with fish slowly swimming round and round, occasionally darting here and there, changing direction unpredictably. Imagine two TV cameras filming the activity of the fish from different points of view. Imagine finally that in another room a person is sitting watching two TV sets receiving the transmission from the two cameras. This person at first might think that he is watching two different fishbowls and fish movements, except that he would notice an amazing correlation in the movements of the two sets of fish. Every time one of the fish in one TV screen unpredictably changes direction by darting to the left or right, a fish on the other screen changes directions also. After watching this activity for a while, this person should be able to deduce that separate images are different perspectives of one reality. According to Bohm, this is what the long road of scientific endeavor, culminating in the experiments of quantum physics, has revealed to us: Our normal world of separate objects is but separate images of one underlying reality. We set up our three-dimensional experiments and then wonder how particles separated by light-years can be correlated, but from the standpoint of hyperspace the particles are right "next" to each other, so to speak; the two apparently spearated particles are the same particle, just as the two apparently separated fish are the same fish.

Flat Land and Hyperspace

We can get an idea of what existence in a higher dimension is like by comparing our three-dimensional existence with a hypothetical two-dimensional existence called Flat Land. Imagine a world that is flat like a piece of cardboard upon which flat, two-dimensional creatures live. Imagine that on this world there are flat, two-dimensional houses and flat, two-dimensional creatures that look like triangles, squares and circles. Because they are two-dimensional, these peculiar characters can go about their two-dimensional business by moving forward or backward and left or right, but "up" and "down" have no meaning in this world. Relative to this world, we would find that three-dimensional creatures like ourselves have supernatural powers. We could peer into their houses from above and watch what they are doing; we could cause strange events to happen at great distances simultaneously; we could cause correlated behavior in objects that seem separated to our flatlanders. We could even cause strange objects to appear out of nowhere.

Suppose we picked up an ordinary salad fork from our three-dimensional world and poked it in and out of this two-dimensional world. A flatland creature observing this event from his two-dimensional world would see only four mysterious dots appear from nowhere, move around in a coordinated manner, and then vanish as mysteriously as they appeared. If we pikced up one of these two-dimensional creatures and pulled him up into our three-dimensional world, then he would have a mystical experience; he would experience a reality for which he has no language to describe. If we then placed him back onto his two-dimensional world, perhaps where a number of his friends are discussing his mysterious disappearance, he would appear to them to materialize out of nowhere. If he attempted to explain to his friends what he had experienced, then he would undoubtedly sound like a crazy fool.

According to Bohm, our observations of electrons and other subatomic phenomena in our three-dimensional laboratories with three-dimensional equipment are not the result of an act of creation of consciousness, but rather an interfacing of a multidimensional reality with a three-dimensional one. Just as our flatlanders experienced mysterious, unpredictable events that were explainable from the point of view of another dimension, so the behavior of electrons and other subatomic phenomena are understandable from the point of view of an overlaying, but concealed, "implicate" hyperspace. Just as the actions of the four correlated dots produced by the three-dimensional fork are seen to be one reality, so our entire world of apparent separated particles that seem to make up separate objects is but a manifestation of one undivided hyperspatial whole.

The major virtue of such an interpretation of the mathematics and experimental results of quantum physics is that the realism of our normal three-dimensional world is preserved. When we walk out of a room, the room is still "there" in a sense. From a hyperspatial perspective, more than a three-dimensional room may be there, but the three-dimensional room is still there for any three-dimensional creature to see. We do not create the room from nothingness.

Many Worlds

There is no logical necessity for believing in one universe any more than there is for believing that Earth is the center of existence. Another interpretation of quantum physics is known as the Many Worlds interpretation. This interpretation preserves Einstein's realism with a vengeance. In the 1950s Hugh Everett III, then a graduate student at Princeton University, decided to see what would happen if the mathematical equations of quantum physics were consistently taken literally. To see how this would work, let's return to our previous experiment.

Recall the experiment attempting to prove that single particles of light pass through only one channel (Figure 2-a). Our result of detecting only one whole unit of energy at detector A or B was consistent with this interpretation. This interpretation was not, however, consistent with the outcome of the experiment with totally reflecting mirrors replacing detectors A and B. The Schrodinger equation depicts waves of some sort passing through both channels, and the experiment with totally reflecting mirrors demonstrates that light, as a wave that splits into two waves, is in both channels. According to the Many Worlds interpretation, there is a simple, but shocking, explanation for the final result. The Schrodinger equation depicts the radiation in both channels as real; the reason we only observe it at one detector or the other is because when a measurement is made, the world splits into two equally real worlds! When the radiation is detected at A, it has also been detected at B. We do not detect it at B because B is an event taking place in another world.

According to this interpretation, all the possibilities delineated by the Schrodinger equation are real. In making an observation of a particular possibility, we are not collapsing a wave packet or creating a reality from a number of possibilities. Rather, like a road with many forks, we are choosing a world to travel on from many possible worlds. All the alternate worlds are paths in hyperspace; there are equally real, but we are forever cut off from them. In every observation we are choosing a branch of reality. If the Copenhagen interpretation implies that nothing is real independent of observation, then the Many Worlds interpretation implies that everything is real. We do not create a universe with an act of observation; we choose a universe that is already there as a possible path.

In the two-slit experiment, when an attempt is made to see if the photons are passing through both slits (Figure 1-c), we found the radiation passing through only one slit or the other. According to John Gribbin, in his book "In Search of Schrodinger's Cat", here is the proper interpretation of what the electron is doing:

Faced with a choice at the quantum level, not only the particle itself but the entire universe splits into two versions. In one universe, the particle goes through [one hole], in the other it goes through [the other hole]. In each universe there is an observer who sees the particle go through just one hole. And forever afterward the two universes are completely separate and noninteracting, which is why there is no interference on the screen of the experiment.

This means, however, that just as there are many routes to the future, there are many versions of "us" that will follow these paths. Because every observation split the path we are on into alternate universes again and again, there are literally billions of alternate paths through hyperspace. These alternate worlds, however, are not parallel to us, as in so much science fiction, but like our three-dimensional view of two-dimensional Flat Land, there are at right angles. Somewhere in this hyperspace is a world where the South won the American Civil War [Harry Turtledove's alternate history "The Guns of the South" explores this possibility], a world where the Spanish Armada defeated the British, a world where John F. Kennedy was not assassinated, and a world where World War III has happened and the human species is extinct. You might take a rest here and contemplate the implications of this interpretation. While you are at it, also contemplate the fact that human beings can think such thoughts and that some physicists take this interpretation very seriously as the only way out of quantum paradoxes. There are no limits to our gestures of understanding with the universe.

The Participatory Universe

As a paradigm for our time, some scientists have found it less shocking to carry out the implications of the Copenhagen interpretation than to believe that each moment we are splitting into 10 to the 100th equally real copies of ourselves. John Wheeler, a distinguished American physicst, has argued that we must abandon the basic tenet of traditional realism--that the universe is in some sense sitting out there for us to uncover. In its place, according to Wheeler, we must boldly embrace the concept of a "participatory universe". (However, Wheeler has been highly critical of those who would use this abandonment of realism as an excuse for believing in the occult or mysticism. See the next section.)

Adherents of this view claim that all vestiges of traditional realism must be abandoned. There is no clocklike world in any sense sitting out there for our observational benefit alone. We do not observe "the real world"; we participate with reality by creating a reality for us. More precisely, we do not create reality; we select a concrete reality from out of an intermingled dance of intangible possibilities. (In the Many Worlds interpretation, all the possibilities are concrete.)

This concept is not as difficult to understand as it may seem. Wherever you are right now there are many hidden, potential manifestations of energy that all of us have come to take for granted int the 20th century. There are many potential channels of electromagnetic information. Although we cannot see them or feel them, there are many AM, FM and TV signals passing by us at any given moent. They are both here and not here. To make these signals of information manifest, to make them concrete, we must "tune them in"; we must have a device such as a radio or TV set to collapse the indefinite electromagnetic waves into concrete electronic digits of information. The human mind is like a radio receiver stuck on one channel. when we set up our three-dimensional laboratory equipment, when we peer into our high-tech telescopes and see galaxies millions of light years away, we participate with the infinite by manifesting one of its faces. It is not a mask; it is definitely there. But only when we observe it; just as radio music is music only when we tune it in.

Our confrontation with the microcosmos has taught us this: The results of our experiments are due to our being on one channel, but the microcosmos is kind enough to reveal to us, through mathematics and observational paradoxes, that there are many other channels. It has taught us that when we go out on a crisp, clear night and peer through a pair of binoculars at the Andromeda galaxy and receive the light that in our normal mode of thinking is 2 million years old, we are instantly creating a 2-million-year-old past. The universe, in a sense, is here because we are here. But we should not get too uppity about this; the universe will do just fine without us. There is still a kind of a past even if I am not looking, just as there is potential music in my room, even if my radio is off.

Mysticism and the Convergence Thesis

One more interpretation of quantum physics deserves some comment. It is a very controversial interpretation, in part because it has attracted a faddish and cultlike following, which claims that the results of modern science have validated a particular religious orientation. The possibility of such a development is one of the reasons scientists are often reluctant to communicate with the general public. An idea, however, cannot be responsible for its misuse by uncritical followers, and the misuse of an idea does not prove the idea false.

For purposes of identification let's refer to this final interpretation as the convergence thesis. Essentially, this view argues that our confrontation with the quantum has demonstrated that Western science, founded upon logic and philosophy of the ancient Greeks, has, after traveling a much different philosophical path, converged with the philosophy of the East, especially the mystical philosophies of Hinduism and Buddhism. This view was popularized in the 1970s by Fritjof Capra in "The Tao of Physics" and by Gary Zukav in "The Dancing Wu Li Masters". According to Capra, "What Buddhists have realized through their mystical experience of nature has now been rediscovered through the experiments and mathematical theories of modern science." Zukov says, "Hindu mythology is virtually a large scale porjection into the psychological realm of microscopic scientific discoveries."

For many thousands of years, it is argued, the mystics have had a cosmological and epistemological view of things that the Western world is just beginning to understand. Cosmologically, Western science has understood only recently that the universe is extremely old. In 1965 the temperature of the universe was measured for the first time, resulting in our present estimate of the age of the universe as 15 billion years old. In the ancient literature of the East one does not, of course, find such precise figures. Instead there are analogies such as the following. Imagine an immortal eagle flying over the Himalayas only once every 1,000 years; it carries a feather in its beak and each time it passes, it lightly brushes the tops of the gigantic mountain peaks. The amount of time it would take the eagle to completely erode the mighty Himalayas is said to be the age of the present manifestation of the universe. Such a conception of time, which predates modern science by thousands of years, is thought to be remarkable, especially when it is compared to the slow realization of Western science and religion to the possibility of a less humanlike time scale.

Eastern mysticism is also consistent with the results of quantum physics. The mystics have always rejected the idea of a hidden clocklike mechanism, sitting out there, independent of human observation. The number one truth is that reality does not consist of separate things, but is an indescribable, interconnected oneness. Each object of our normal experience is seen to be but a brief disturbance of a universal ocean of existence. Maya is the illusion that the phenomenal world of separate objects and people is the only reality. For the mystics this manifestation is real, but it is a fleeting reality; it is a mistake, although a natural one, to believe that maya represents a fundamental reality. Each person, each physical object, from the perspective of eternity is like a brief, disturbed drop of water from an unbounded ocean. The goal of enlightenment is to understand this--more precisely, to experience this: to see intuitively that the distinction between me and the universe is a false dichotomy. The distinction between consciousness and physical matter, between mind and body, is the result of an unenlightened perspective.

Epistemologically, our so-called knowledge of the world is actually only a projection or creation of thoughts. Reality is ambiguous. It requires thoughts for distinctions to become manifest. We have seen that in the realm of the quantum, dynamic particle attributes such as "spin", "location", and "velocity" are best thought of as relational or phenomenal realities. It is a mistake to think of these properties as sitting out there; rather, they are the result of experimental arrangements and ultimately the thoughts of the experimenters. Quantum particles have a partial appearance of individuality, but experiments show that the true nature of the quantum lies beyond description in human terms. Our filters produce the manifestations we see, and the result is just incomplete enough to point to another kind of reality, an ambiguous reality of "not this, not that".

For the mystic, the paradoxes of quantum physics are just another symptom of humankind's attempt to describe what can only be experienced. We are like a man with a torch surrounded by darkness. The man wants to experience the darkness, but keeps running senselesslly at the darkness with his torch still in hand. He does not realize that he must drop the torch and plunge into the darkness. The proliferation of philosophical interpretations of quantum physics is a symptom of the shipwreck of a traditional Western way of understanding, of our inability to "let go" of our Western torch--our traditional logic and epistemology. It is also a symptom of our inability to let go of our egocentricity, our persistent attempt to define everything in purely human terms, as if we were somehow special and separate from the rest of the universe. Like a nervous, self-centered teenager at a party, concerned only with what others think of him or her, our entire field of vision and understanding is narrowly defined in terms of "me". Because of our fear of letting go, we are missing much that is right in front of us.

According to this interpretation, the mathematics is complete just as it is. What the Schrodinger equation depicts for microscopic objects is also true for any macroscopic object. The universe is not full of separate objects, people and places. Rather, it is an unbounded field of entangled possibilities. Because of the level of our conscious awareness, we fail to realize that duality, ambiguity and interdependence are the rule rather than the exception. Mathematics may be one of the closest ways we can come to representing this in terms of a human language. All languages, however, are ultimately inadequate. Myths, stories, analogies, pictures, mathematical equations--all such symbol systems can just point to what can only be fully understood through a visionary experience.

In the episode entitled "The Edge of Forever" in the "Cosmos" television series, Carl Sagan visits India, and by way of introducing some of the bizarre ideas of modern physics, he acknowledges that of all the world's philosophies and religions those originating in India are remarkably consistent with contemporary scenarios of space, time and existence. However, adamantly skeptical of the knowledge value of a nonrational mystical intuition, he concludes that although these religious ideas are worthy of our deep respect, this is obviously a "coincidence". Using natural selection as a model, Sagan proposes that this consistency is "no doubt an accident" because given enough time and possible proposals, given enough creative responses to the great mystery of existence, some ideas will fit the truth just right.

Other critics of the convergence thesis have not been as charitable. They argue that it is just plain silly to interpret an ancient belief system, founded upon certain psychological needs and within a historical context, in terms of any modern perspective. It is obvious, they argue, how the Hindu and Buddhist beliefs could soothe people living under extreme conditions. If our day-to-day reality is but a fleeting manifestation, then the vicious misfortune and meaningless suffering of this world are not real. For these critics, the methodology of psychological need as an origin of these ideas implies there is no connection. By revealing the obvious psychological motivation for a set of beliefs, it is argued, one can question the truth of these beliefs. To further suggest that there is any connection between these beliefs and the results of rigorous experimental science is ludicrous.

Both of these arguments are flawed. If the ideas of Hinduism and Buddhism are simply the result of a lot of guessing, and the serendipitous contingency of evolutionary processes the appropriate model, then shouldn't all the guessing that takes place over time be consistent with a macroscopic environment, not a microscopic environment with which a primitive people have no experience? And even if it is true that a belief system serves a set of psychological needs, does this prove the belief system false? Many scientists are also surely motivated for many reasons to hold the beliefs they do: a philosophical perspective, the need for certainty, or the need for security (be it a government grant or tenure at a prestigious university). That scientists have biases and motivations to believe what they do does not prove that what they finally believe is false.

Both of these arguments, however, do reveal a sobering point. The philosophical consistency between Hinduism and Buddhism and the results of modern science does not prove much by itself. Historically, we have seen many instances of a philosophy or a religious view being consistent with the science of a time, and a consequent rush to claim that the new science validates a relgion or a philosophy. For both Copernicus and Kepler, the heliocentric system of the planets was consistent with their Neoplatonism and the idea that the sun was the "material domicile" of God. Similarly, for Bruno the heliocentric system was consistent with a larger universe and a greater God. For Newton a universe based upon the laws of universal gravitation was consistent with a conception of God as a master craftsman, a creater of an almost perfect machine who left a few defects to give Himself something to do. For some of the initial supporters of Darwin, natural selection was interpreted as a vindication of a philosophy of inevitable progress based upon a capitalistic economic system.

Perhaps the more pertinent question, applicable to all the interpretations of quantum physics, is not which offered paradigm is the truth, but which one will give us the most mileage? Which one, if followed as a guide, will be the most fruitful in stimulation the imagination of the next generation of scientists in devising new ideas, mathematical relationshiops, and experiments? In this reading we have not given much attention to the area of modern physics that recently has gotten the most notoriety. Most physicsts, concerned with the daily demands of obtaining research grants and Nobel Prizes, have simply filed such demonstrations away and continued with the Einsteinian quest, searching for more and more exotic particles, new "things" that will prove the supersymmetry theories, unifying all the known forces of nature and catapulting our understanding to the first microseconds of the universe and perhaps beyond.

Yet in spite of Nobel Prizes for the discovery of some of these new particles and public pronouncements that the end of the Einsteinian quest is near, one senses that all is not well with this approach. Physicists themselves complain that the proliferation of particles necessary to explain everything is too complex to be consistent with a simple universe. One senses many ad hoc approaches and a situation not unlike followers of Ptolemy adding epicycle after epicycle to make the data fit. Some experiments reveal serious anomalies. Particles that allegedly consist of a "bag" of quarks are not supposed to pass through each other, but in some cases, if the spins are just right, they do! One senses that nature is not yet ready to succumb completely to our lates gestures of understanding.

Every past success at understanding has produced new mysteries. Why should it be any different now? Perhaps the results of quantum physics discussed in this chapter are revealing to us a great discovery after all. This great partner we call the universe is not a static personality, but grows and is formed by us, as we are by it. There is every reason to believe that our romance will continue, that there are many mysteries left for a new generation of physicists. Although there have been many pretenders since the time of Kepler, no one has yet read the mind of God.

Concept Summary

One of the major scientific questions of this century seems so simple. What are electrons, photons, and other subatomic objects that have made the amazing technological revolution of this century possible? After more than 70 years of asking this question, no consensus on an answer has been reached, and widely divergent views on the nature of reality and the role of science in dealing with reality have resulted. Experiments with subatomic phenomena show effects that are difficult to reconcile with our normal view of an objective world. Particles of matter are independent objects located in one place at a time. Waves can spread out and/or split and be in many places at the same time. All experiments with subatomic phenomena show wave-particle duality; rather than a definitive, objective world, reality seems to be ambiguous at the quantum level.

Although a very successful mathematics was developed enabling physicsts to interact with, explore, and extend applications of subatomic reality, the interpretation of the mathematics is a philosophical muddle. One of the most influential interpretations of quantum physics was that of Niels Bohr and what has come to be called the Copenhagen Interpretation. According to this interpretation, the ambiguity and complementarity of quantum experimentation reveal a startlingly pragmatic, epistemological discovery: Our macroscopic experiments must be conducted from the point of view of a human conceptual reference frame, but nature at the quantum level need not, and apparently does not, conform to macroscopic concepts. Accordingly, what we measure in our quantum experiments are the results of our relationship with nature, not nature itself. Between moments of preparation and measurement of quantum events, there is nothing definitive to know, understand, or measure, because nature has revealed to us that there is nothing there that can be conceptualized in human terms. Subatomic phenomena such as photons and electrons become definitive objects only after measurements are made with macroscopic equipment.

Because Einstein was convinced that the goal of science is to reveal the clockwork mechanism of nature itself, not just the probabilistic results of our relationship or experimental tinkering with nature, he objected to this interpretation. Quantum theory could not be a complete theory. For Einstein there was an underlying reality that we did not understand yet; for Bohr, the goal of knowing an underlying, definitive reality was an antiquated philosophical relic of classical physics. For Einstein, the Copenhagen Interpretation implied defeatism at its best and classical idealism at its worst. For Bohr, many fruitful explorations still exist, relationships yet to be described and mathematical trails yet to be followed, but the search for a "hidden" reality will not be one of them.

The work of Bell and Aspect has resulted in a strong experimental confirmation that in the quantum realm it is wrong to think of quantum phenomena as independent hidden entities influenced by independent local circumstances. Like Newton confronting the problem of gravity, most physicists in the 20th century have been trained to adopt a pragmatic or instrumentalist stance to these results--science is supposed to describe the objective properties of experiments, not speculate on a hidden reality between measurements. But the compelling need for a philosophical understanding has produced numerous proposals.

Some physicists have argued that the success of quantum theory shows that far from being a secondary quality, consciousness produces a definitive, relationship-reality from an ambiguous, featureless whole. David Bohm has suggested that an interpretation of radical neorealism is still possible, one that describes a multidimensional hyperspace of implicative wholeness "behind" the explicative or definitive reality of our common-sense world. Others have argued that a rigorous interpretation of the mathematics of quantum theory reveals that the divergent results of interactions with the quantum realm can be explained in terms of real, branching, or splitting universes.

Still others have claimed that we must abandon traditional realism altogether. The world cannot be pictured as "sitting out there" for us to uncover; our "participation" with an intermingled dance of possibilities yields a concrete reality. Finally, some have claimed that quantum theory represents a convergence of Western and Eastern philsophies; modern science has uncovered the same indescribable, interconnected oneness discussed by mystics for centuries. For the mystic the result of quantum experiment is like a man with a torch surrounded by darkness. The man wants to experience the darkness, but keeps running senselessly at the darkness with his torch still in hand. Most scientists believe this is total nonsense.

One thing seems clear. There are plenty of mysteries left to stimulate the next generation of physicists.