http://www.scipool.com/doc/doc200302100430.html

The Needle's Tip that we would call infinitesimal, is, in its "scanning electron micrograph," the corbelled and tunneled and buttressed and corrugate Tower of Babel as Bruegel envisioned it under construction
Albert Goldbarth

More and more sophisticated radio, microwave and optical telescopes proved Einstein's Theory of relativity correct and through the century they detect pulsars or heard the background radiation that is the very echo of the universe's birth. With each discovery we have realized more and more the range of the universe and the awesome nature of it. However, when we look in the opposite direction so to speak, as we look into the world of the particle, the wonder grows even more. Since the renaissance, when an early science began to peer into a microscope, we discovered surprise after surprise. The microscope reached its limits and we resorted to other tools and methods to explore smaller and smaller scales. Only then did the world that we perceive began to break down and the constituents of matter and their behavior seemed not to pare with the everyday macro world in which we lead our lives. In short, as scientists developed a thorough and all encompassing theory of the of the micro-world, our building blocks became more and more non sense. In this chapter we will look at some of the most astonishing and mind-bending discoveries science made during this century. These discoveries deal, not as Einstein's, with the place we inhabit, but with the world is made of. Quantum deals with the atom and its particles.

As we have seen from the previous chapter, at the end of the nineteenth century, physics worked within certainties. The Newtonian model of the universe presented certain paradoxes which were difficult to solve but which also most scientists believed would be solved without disturbing Newton's framework radically. As conservative as Einstein and many other scientists were, their findings at the beginning of this century did not merely revolutionized physics and science, but actually shifted the paradigms within which science worked. As we have seen, Einstein's relativity did just that. The general theory argued that galaxies, stars and planets are free-falling through a four dimensional space-time which was curved in the fourth dimension.

While Einstein's conclusions seem somehow mind-boggling, Einstein himself as well as many of his contemporaries did not only try to solve the cosmological paradoxes they inherited from classical mechanics, but also worked with some of the paradoxes and problems that arose in the study of the atom and its components. In fact, if any branch of science would challenge common sense and to an extent revolutionize our conception of the world we live in, quantum mechanics would do it to boot. Quantum mechanics is so puzzling in its assertions that both scientists and philosophers have either rejected or shrugged at its findings. Einstein's famous remark that God does not play dice with the universe was a direct response to one of Quantum's most cherished premises. The Columbia University philosopher David Z. Albert has written that quantum is " an unsettling story," "the most unsettling story, perhaps, to have emerged from any of the physical sciences since the 17^th century." ^{[ Note 1 ]} Similarly, in his book Quantum Reality: Beyond the New Physics, Nick Herbert argues that with quantum, scientists "lost their grip on reality." ^{[ Note 2 ]}

In one of the best popularizations of the subject, David Lindley explains why quantum seems both to oppose the logic of classical physics and to seem, using a word which quantum physicists have adopted, so weird:

This is the heart of the fundamental issue. In classical physics, we are accustomed to thinking of physical properties as having definite values, which we can try to apprehend by measurement. But in quantum physics, it is only the process of measurement that yields any number for a physical quantity, and the nature of quantum measurements is such that it is no longer possible to think of the underlying physical property (magnetic orientation of atoms, for example) as having any definite or reliable reality before the measurement takes place. ^{[ Note 3 ]}

The difficulty or weirdness of quantum stems from the fact that the physical reality it describes cannot be measured because once the measurement is done that reality has changed. Like most of quantum, the latter statement seems paradoxical. More paradoxical, however, is the fact that if one looks at the different branches of science and attempts to pinpoint the most precise by the way each science is able to predict exact outcomes, then quantum is the most exact of science. The rub, of course, is that whatever precision quantum yields, it does so only to defy our common sense.

In this chapter we will attempt to make some sense of quantum mechanics: what it studies, what its conclusions are and see how these conclusions tie up with the macro-cosmos which we dealt with in the previous chapter. Quantum studies the behavior of the atom and its particles. It does so by predicting the probabilities of possible results. In other words, an analogue discipline to quantum in the macro-world would be ballistics. Ballistics takes a projectile, a launcher, friction, gravity, etc. as its variables and through formulas calculates the way in which the missile will travel and where it will land. In other words, ballistic takes certain variables and converts them into possible results. Similarly, quantum takes an atom and calculates the probability of its charge or color. The difference here, of course, is that ballistics functions in a classical universe. Ballistics experts have to consider two things, matter, the substance of projectile and launcher and fields, in this case the earth's gravitational field. The bullet is made out of metal, matter, follows a trajectory due to inertia and if not stopped, eventually lands because the earth's gravitational field pulls it. Quantum is not that simple.

When people talk about quantum they are often talking about the various interpretations which scientists have tried to frame in order to describe or explain what quantum is saying. For instance, Niels Bohr, who is known for the Copenhagen interpretation, would argue that quantum tells us that there is no deep reality. Like the Bishop Berkeley three centuries before him, Bohr argued that the world we see around us might be real enough, but its components, what is built on, is not real. It follows then, that the second premise of the Copenhagen interpretation pivots around the idea that, since there is no deep reality, what the scientist observes is a phenomenal reality. Phenomenal reality argues that in the absence of an observer phenomena do not exist. In other words, the scientist creates reality as he determines the electron's spin or momentum.

To the layman, the claims of the Copenhagen interpretation seem outrageous. But Bohr, who framed its main premises, argued them as pragmatic. For him, the scientist's task involved the study of natural phenomena without exploring the philosophical, existential, ethical implications of the findings. Many scientists have rejected this position. Chief among them was Einstein who possessed an almost mystical attitude towards science. In fact, Einstein spent the last years of his life attempting to reconcile the classical physics of his general relativity to the tight findings of quantum. Later other scientists would offer different interpretations. These later interpretations developed many years after quantum had established itself as the most precise branch of scientific knowledge. We will look at these interpretations closely, since some involve interesting claims, others seem just as outrageous, and others still seem to offer viable routes for future research. In fact, the latter seem to us, to open completely new vistas. Before we move into these interpretations, however, we would like to delineate quantum's main premises, for it is impossible to understand how any science, let alone one that deals with the atom and its particles, would inspire such various and strange reactions.

Most textbooks and popularizations of quantum start by discussing light. The reason for this is fairly simple, Quantum theory was invented to deal with the interaction of light with atoms. Only later, once quantum solved this problem, did scientists try to test whether their discoveries were also applicable to a larger array of entities, whether quantum could reveal the structure of atomic nuclei and the other sub-nuclear particles and reveal the nature of solid, liquid and gas. As more and more physicists attempted to apply quantum theory to every particle, they discovered that the theory did not merely explain the behavior of light. It also clarified most of the mysteries of the atom and of matter to such extent that we talk about a cosmic genesis, about the moment when the universe began, cosmology gives away to quantum.

What exactly did quantum have to say about light? To understand quantum's breakthroughs, we should look, at least briefly, at the different problems that scientists set out to resolve. One of the most conservative physicists at the turn of the century might have started the quantum chain reaction as he tried to resolve a rather puzzling problem which has come to be known as the black body radiation. Physicists in the 19^th century knew that objects have an intrinsic color. During spring leaves are green. Most woods fall within the range of brown. These objects are made up of tiny pieces of matter. Whenever these pieces move, they shake waves into the attached electromagnetic fields which our eyes, optic nerve and brain interpret as color. The faster the particles move, the higher the frequency of the light that is shaken off. The intensity of a particle vibration can, of course, be altered by applying extra energy. We witness the latter phenomenon everyday when we turn on a light bulb. However, according to physicists black objects do not have an intrinsic color. Still, if one heats up a piece of metal, the metal will glow red. As physicists searched for an answer to the puzzle, they came with the same results: black bodies should glow bright blue. Max Plank tried to resolve the problem by adding a constant -Plank's constant - in his calculations. He assumed that the particle had energy and that its energy was equal to an integer multiplied by the frequency of the particle vibration and the constant:

E=nhf

The use of the constant seemed arbitrary and though it resolved the black-body glow, to most scientists it seemed gimmicky because for Plank the energy of the particle has to be a multiple of its frequency and the constant. The constant itself was Planks way to facilitate the math. In fact, no real discovery, he planned to get rid of it. However, every time that he made his calculation and dropped the value of the constant to zero, he found out that his results came to be the same as previous results: the black body would glow blue. What the formula ultimately showed was that energy came in bundles whose denomination was fh. These bundles, these quanta, were to begin a revolution since they would force scientists to rethink all their premises on the nature of matter.

For starters, since quantum theory was developed to solve the problem of the interaction of light with particles, the scientific conception of light changed completely. Once this conception changed scientists would apply their new discoveries to more and more problems until eventually they realized that all of matter, the nature of solids, liquids and gases, the structure of the nucleus, etc., behaved according to quantum principles. These principles, while strange, are actually quite simple. For the entire nineteenth century, scientists believed that light was a wave of electromagnetic energy. They though that a beam of light shining on a piece of paper. Since waves are the manifestation of a force, it followed that like all waves, a light wave could exert its force and in doing so, disturb the surface where it shone. In other words, just as sound waves push the molecules of air, light waves knock electrons off the surface where it shines. According to classical physics, the intensity of the wave determines the disturbance of the surface it affects. Quantum scientists discovered, however, that this did not hold true for light. A light with greater intensity does not knock the electrons with more energy. This last discovery is one of the many confusing findings in quantum. To understand how contradictory to common sense it is, one only needs to visualize the different waves of water. Imagine throwing a small rock into a pond. The wave will ripple outward and everything in its path will be disturbed. The leaves floating on the surface would act like electrons and they would be "knocked" by the wave. If instead of throwing a small rock, one would manage to carry a boulder and hurl it, the energy with which the leaves will move will be greater, just as the force with which a tidal wave knocks us of the beach would be greater than that of a ripple. What quantum refers to as the photoelectric effect tells a different and less common sense story. If the person conducting an experiment would increase the intensity of the light beam, more electrons would be knocked of the surface, but they would emerge with the same energy. In fact, what the photoelectric effect confirms is that in order to transfer greater energy into the photons, one has to increase, not the intensity but the frequency. The energy of light does not depend on intensity but its color. Blue light is a high frequency light and knocks electrons harder than red light which is low frequency. The experimenters' results tell us then that the short fast ripples are more powerful than the long ones.

The person who explained the strange behavior of light was Einstein. Taking Plank's constant, he argued that light affects the surface it shines on, not like a wave, but like a shower of particles. This conclusion, of course, contradicted one of scientist's most cherished certainties: namely, that light was a wave. From Maxwell's time, light was understood as a manifestation of the magnetic field. Moreover, the behavior of light in our everyday perception seems to contradict the fact that light could be a particle. A beam of light can spread over an area, be split, redirected or diffracted and finally can cross paths with another beam. All this qualities seem to suggest that light is indeed a wave. Waves spread, split, redirect and cross paths with other waves. Particles on the other hand are confined to tiny regions; their travel is constricted to a single direction and they cannot interfere with each other without crashing. In short, particle and wave seem irreconcilably different. Nevertheless, both Einstein's solution to the photoelectric effect and experimental evidence tell us otherwise. They argue that light can be both wave and particles, that light interacts with a surface through a shower of particles which are divided into "units of energy." The denomination of these units would come to be known as "photons."

If Plank's and Einstein's solution seemed contradictory, when some of those findings began making their way around the scientific community and scientists attempted to apply those findings to other aspects of matter, the results were even stranger. Plank, Einstein and Compton might have shown that waves were also particles. In France, however, Louis de Broglie argued that just as Einstein's had demonstrated that waves of light had particle qualities, the particles of matter also have wave properties. In fact his Ph.D. thesis merely utilized Einstein and Planks formulations. For him, each particle of matter could be associated with a wave whose temporal and spatial frequencies could be understood as energy and momentum. De Broglie's arguments, in short, complement Einstein and Plank's findings. However, they might be more difficult to digest since they imply that matter can be turned into a field. In other words, they break down the matter/field distinction and tell us that everything is made out of what scientists have come to call "quantum stuff."

While these findings constitute the backbone of the world which quantum physics deals with, they are not quantum theory per-se. All the way to 1925, scientists might have been discovering new and surprising things about the atom. Nevertheless, to interpret them, they had to utilize the schemes provided by classical physics and then fiddle with their formulae in order to fit the experiment. According to Max Jammer, the situation was a "lamentable hodgepodge of hypotheses, principles, theorems and computational recipes." ^{[ Note 4 ]} Quantum theory itself though, is anything but hodgepodge. Systematized and exact, the theory is a method of representing quantum stuff mathematically. Quantum mechanics, then, is a representation of the world through symbols where a mathematical value is given to quantum stuff, a scientific law describes how this quantity transforms and finally, some sort of rule determines how the mathematics can be translated into the phenomena of the world.

The first of these theories to be fully formulated was Werner Heisenberg's. Known as matrix mechanics, Heisenberg developed his system in 1925 while he was recovering from an illness in the island of Heligoland. In his memoir he would recall that:

At 3 a.m. one night he could no longer doubt the mathematical consistency and coherence of the kind of quantum mechanics to which my calculations pointed. At first I was deeply alarmed. I had the feeling that, through the surface of atomic phenomena, I was looking at a strangely beautiful interior, and felt almost giddy at the thought that I now had to probe this wealth of mathematical structures nature had so generously spread out before me. ^{[ Note 5 ]}

Heisenberg's starting assumption seems now very simple. However, it was not so when he develop his matrices. It involved something he had heard when he was working in Gottingen with Max Born: namely, that a physical theory should concern itself with things that could actually be observed by experiment. While at first the idea might seem matter a fact, it was not back then and, in fact, it involved shedding the paradigms from classical physics which scientists kept applying to the atomic world. No one had seen an electron following elliptical orbits around a nucleus. The model was a borrowed from classical physics. What experiment observed where the two particle and wave state of the electron, the spin and momentum. What experiments confirmed was that there were transformations between to states.

To deal with these transformations and relationships between two states, Heisenberg had to resort not to ordinary numbers but to matrices. Scientists attempting to popularize quantum have suggested that Heisenberg's matrices resemble mileage tables in maps. An even easier analogue would be a chessboard. Like Heisenberg's matrices, the squares on a table are represented by unique coordinates (a1, b1 and so on). Like in a chess game, where the "state" of the game can be represented by the notation of these unique coordinates, in Heisenberg's matrices, the "state" of an electron or a particle, the "quantum transitions" can be described through a similar notation that links the initial and final states.

Heisenberg's matrix mechanics, managed not only to replace the equations of classical mechanics, but to subsume many of its principles like the conservation of energy. Somehow, though, the theory did not manage to be a great success in the scientific community. This failure stemmed in part from the unfamiliarity of the math it relied on and in part from the fact that it did not provide a physical picture of the phenomena it represented. There were no orbits, no waves, no particles. So when only a year after Heisenberg's matrices were published, Erwin Schrödinger came up with a quantum theory, wave mechanics, which utilized the image of the familiar waves, the scientific community adopted the model so that it became the standard.

Developed in 1926, wave mechanics, like matrix mechanics solved the problems of quantum interactions. Unlike matrix mechanics, though, wave mechanics does not rely on an unpopular branch of mathematics but on mathematics that were widely used by most physicists already. In short, Schrödinger used wave equations, the same equations that described waves in the everyday world like ripples or sound waves. So while Heisenberg's model assumes that electrons are particles. Schrödinger assumed that the electron was a wave. Both theories come up with the same result and eventually Schrödinger himself, with Carl Eckhart and Paul Dirac would show that the two models are mathematically equivalent to each other; they are, in short, two sides of the same coin. The latter discovery was made to Schrödinger's chagrin, since he originally formulated wave mechanics to restore sanity to quantum physics, attempting to elide weirdness like quantum leaps, the discontinuous and random transitions between quantum states.

In fact, neither of the two theories, nor the theories to come would get rid of the weirdness. If quantum is puzzling, it is because it violates at least two of our central intellectual paradigms: causality and identity. In a quantum leap an electron in certain energy level, the allowed state of amounts of stored energy, can jump instantly into another energy level, emitting or absorbing energy as it does so. There is no in between state and the leap happens outside time as it where, since it does not take any time for the leap to occur. Consequently a quantum leap violates our cherished sense of causality, logic and continuity. The "and" and "either" which George Boole codified into the symbols that would anchor his Boolean logic loose their habitual meaning. Similarly, in the quantum world, the entities, our capacity to identify certain characteristics and tack them to the components of the atoms as if the atom where, like living beings, subject to taxonomy does not work.

The almost archetypal experiment that quantum physicists resort to explain the puzzles of quantum mechanics is the double slit experiment. Richard Feynman argued that the experiment contained "the central mystery" of quantum because it presents "a phenomenon which is impossible, absolutely impossible, to explain in any classical way, and which has in it the heart of quantum mechanics." Feynman would add: "In reality, it contains the only mystery...the basic peculiarities of quantum mechanics." ^{[ Note 6 ]}

Originally developed in the early 19^th century by the English physicist Thomas Young, to confirm the wave theory of light proposed by Christopher Huygens and which opposed Newton's corpuscular theory, the experiment is amazingly simple: it only involves light being shone onto a screen which has a narrow slit cut in it. The light passes through this slit and shines onto another screen where, this time, two slits have been cut in it. The light coming out of the two holes shines upon a blank wall where it makes a pattern of shadows and light. The pattern is not unlike the bar code in most products we buy now a days, except that the bars are less defined and more regular and this regularity is due to the interference of two overlapping waves. The behavior as such, then, is akin to what happens with sound waves in home stereos. If one were to angle two speakers so that the sound waves coming out would actually crash against each other. In such case, one or another sound would be eliminated. In a big symphonic piece for instance certain frequencies, like the sound of the flute or the clarinet would not be heard. Similarly with the two slit experiment, the bars that appear in the final screen entail that the bright bars are where two sets of waves folded together and make a swath of light. The dark spots, on the other hand, mean that two waves interfered and cancelled each other.

Young's results could not be duplicated with particles. Imagine that instead of light beams one were to let pellets through the holes. The pellets would go through the first still and then according to gravity and inertial forces fall through either hole. At the end, however, the pattern of light and dark bands would not appear. Instead, what we would have two piles of pellets, one behind each hole. The curious or rather puzzling aspect of the experiment emerges when scientists use a beam of electrons. We should remember from our earlier discussion of the photoelectric effect, that, thanks to Einstein, we have come to think of electrons as particles. If electrons are fired through both screens and arrive not onto a screen, but onto a surface where we can measure them, in this case, a phosphor screen, a screen which like a computer or TV screen records the electric impulse of each electron, what we get is exactly the same pattern. Even if the electrons were fired one by one, eventually, the experiment displays the same results: each electron arrives at a particular spot on the screen and makes a single spot of light. In fact, after 70,000 electrons to pick a sum are fired one by one, the pattern is incredibly similar than in the initial experiment since the screen "remembers" each spot of light as the pattern builds up.

Ultimately, the Young experiment demonstrates, not merely that light is a wave and not a corpuscle, but something more puzzling: quantum entities travel like waves but arrive as particles. Hence, the efficiency of both wave and matrix mechanics despite the fact that the latter considers particles and the former waves. Furthermore, the implications of this experiment go beyond the mere particle wave duality. What they point out is what Feynman called the "only mystery." Let us repeat here for this is a crucial experiment and again as Feynman argued: "any other situation in quantum mechanics, it turns out, can always be explained by saying, 'You remember the case of the experiment with two holes? It's the same thing." ^{[ Note 7 ]} So here it goes: Single particles are being shot through the two screens and each makes a single spot on the screen. Common sense would tell us that each particle goes through one or another of the two holes. However, as more and more dots reach the screen, the pattern that emerges is the classic interference pattern passing through two holes. The electrons not only seem able to pass through both holes at once, but (and we will return to this in later chapters) to "choose" and remember. In short, the particles seem aware of past and future so that they remember the pattern and choose to make their contribution to the pattern.

The implications of the experiment have been explored and interpreted in many different ways. Each of these interpretation raises a plethora of philosophical questions about our world being that what quantum scientists are dealing with is the fabric of the world. We have already touched upon the Copenhagen interpretation which contends that there is no deep reality. However, the Copenhagen interpretation is not the only one. Faced with the electron's particle-wave duality and also with the fact that the electron seems to be aware of the observer and affected by the act of observation so that it will modify its behavior accordingly, other physicists like Hugh Everett and Bryce De Witt ^{[ Note 8 ]} and most recently David Deutch in The Fabric of Reality have argued that whenever the world is faced with a choice at the quantum level, in other words, whenever an electron marks one spot in the screen and not another or chooses one slit over another, then the universe divides into two or as many parts as there are choices, so that all possible options are followed. In other words, the many worlds interpretation argues, as DeWitt wrote that 10100 slightly imperfect copies of oneself are constantly splitting into further copies."

The many-worlds-interpretation, like many interpretations, can be mathematically proven. In fact, in its fully developed mathematical form it agrees with the Copenhagen interpretation. However, even though it has proven useful for cosmologists, who have begun to speculate about multi universes or multiverses, at its most literal its flaws are the kinds of flaws that, unfortunately, too many scientists are prone to, namely, allowing a theory which is, as we shall see shortly, precise but in no way complete, to make larger claims. In other words the interpretation is over-extending the results to such extent that even the prose that explains it has that sophomoric ring one finds in enthusiastic but undisciplined philosophical investigations. David Deutch is a prime example of this. After arguing that "the quantum theory of parallel universes is not the problem, [but] the solution ...the explanation -the only one that is tenable - of a remarkable and counter-intuitive reality," Deutch waxes on:

Not only do the copies of an abject have any privileged position in the explanation of shadows [by shadows Deutch means the particles in other universes] that I have just outlined, neither do they have a privileged position in the full mathematical explanation provided by quantum theory. I may feel subjectively that I am distinguished among the copies of the tangible one, because I can directly perceive myself and not the others, but I must come to terms with the fact that all the others feel the same about themselves.

Many of those Davids are at this moment writing these very words. Some are putting it better. Others have gone for a cup of tea. ^{[ Note 9 ]}

Deutch's speculations are, of course, a good example of a central fallacy to which scientists incur. The fallacy is a semantic one at heart and it involves the indiscriminate application of scientific terms, of terms which have a very specific meaning in the laboratory but do not mean the same to the world outside the lab.

At the heart of the matter also one has to consider the fact that quantum, for all its precision in describing the micro-world and the behavior of the atom and its particles is in no way complete. Quantum can tabulate the strong and weak nuclear forces as well as the electro-magnetic ones. However, as of now, no one has managed to integrate gravity into quantum's scheme. The reason s for this failure are diverse. One of them can be gathered if we remember from the previous chapter that inertial mass and gravitational mass are undistinguishable in Einstein's general relativity. The second reason has to do with the scales with which quantum works. Gravity is too weak a force. This means that the effects of gravity can not be detected within the Plank length and Plank time. ^{[ Note 10 ]}

Few interpretations of quantum take the theories incompleteness into account. To admit quantum incompleteness is not to imply quantum's failure. In fact, we, as many scientists do, among them the mathematician Roger Penrose, the physicists Danah Zohar and John Gribbin, believe that ultimately quantum will unravel not merely the mysteries of the physical world, but deeper more complex mysteries, the mysteries of both molecular memory as seen in the formation of DNA and our own memory and consciousness. The second half of this book will dwell of these subjects. ^{[ Note 11 ]} However, while, in the future, these mysteries might be unraveled by many of the principles of quantum mechanics, this will only happen until the loopholes, so to speak are patched.

One of the quantum interpretations that admits these loopholes and points out possibilities for a future quantum was proposed by David Bohm. Unfortunately, Bohm's ideas as well as his reputation has been subject to the vagaries of academic politics. Born in Pennsylvania in 1917, Bohm graduated from Pennsylvania State College and, like many 20^th century physicist, he sharpened his skills under Oppenheimer first at Berkley and then at Los Alamos. Like Oppenheimer, Bohm had not merely a philosophical bent but also a conscience and asked to implicate colleagues in McCarthy's HUAC he refused and was dismissed from his post in Princeton University. His Marxist leanings made his suspect to the community. While writing what is one of the clearest and most accessible textbooks on quantum mechanics, Bohm became convinced of quantum's flaws and developed a new interpretation variedly known as pilot wave, undivided whole or hidden variable interpretation. His impulse for this interpretation was a theory that amounted to more than mere statistics, a theory that would have some relevance in the world:

All that counts in physical theory is the development of mathematical equations that permit us to predict and control the behavior of large statistical aggregates of particles...This sort of presupposition is indeed in accord with the general spirit of our age, but we cannot thus simply dispense with an overall world view...Indeed, one finds that physicists are not actually able just to engage in calculations aimed at prediction and control: they do find it necessary to use images based in some kind of general notions concerning the nature of reality." ^{[ Note 12 ]}

The interpretation with which Bohm attempted to make quantum adopt an overall view has been branded as deterministic. However as we shall see, quantum weirdness itself has redeemed the interpretation from this label. Many have also pointed out the main flaw of the interpretation. It seems to rely on that bugbear Einstein put down so often, action at a distance, the idea that interactions between objects operate without any intervening mechanism.

Despite all detractors, the interpretation is important and if flawed, it definitely, as Timothy Ferris has argued points to the "mists of a possible future science." ^{[ Note 13 ]} Bohm's initial assumption is that the usual versions of quantum mechanics are flawed because incomplete. These lack of completion stems from the fact that, according to Bohm, there is an underlying layer of reality, a sub-quantum world which contains additional information about the world. This additional information is in the form of hidden variables, which predict the precise outcomes of particular measurements. In other words, Bohm's hidden variables assume and argue for a sort of overall "consciousness," a controlling force that determines the outcome of events.

Even though such theory is infinitely more elegant and seems to have more common sense than both the multiple universe or the Copenhagen interpretation, scientists dismissed it off-hand at first because the mathematician John Von Neumann proved mathematically that the hidden variables could not work in the quantum world and then because most scientists feared the assumption that to determine the outcome of multiple events, the hidden variables assume action at a distance.

Recently though the hidden variables interpretation has had a sort of revival. David Z. Albert has been one of its main proponents:

This is the kind of theory whereby you can tell an absolutely low-brow story about the world, the kind of story (that is) that's about the motions of material bodies, the kind of story that contains nothing cryptic and nothing metaphysically novel, and nothing ambiguous and nothing inexplicit and nothing evasive and nothing unintelligible and nothing inexact and nothing subtle... ...in which the whole universe evolves. ^{[ Note 14 ]}

Other than philosopher-scientists like Albert, the interpretation has been redeemed by the Aspect experiment. The Aspect experiment was actually a series of experiments run by Alain Aspect and his colleagues. The experiments established that what Einstein labeled as the "spooky action at a distance" really operates in the quantum world. The core of the experiment involves the polarization of photons. Photons can be thought as coming with arrows that wither point "up" or "down." If an atom is stimulated so that it produces two photons, the photons will head to different directions canceling each other. One will be up, the other one down. According to standard quantum theory, the photons exist in a superimposition of states. In other words they can be "up" or "down' until the experimenter measures. When the experimenter measures there is a collapse of the wave function and the photon settles into one of the two states. The experiment took this into account. However, it used it in its favor by measuring one photon only. The experiment revealed that in taking the measurement of one photon, the wave function of the second unmeasured photon collapsed at precisely the moment that the measurement of one photon was taken. Once one photon collapsed into a definite state, the other photon, without being measured itself, also settled into a definite state.

The instantaneous response of the second, unmeasured photon to what happened to the first measured photon belied the impossibility of action at a distance. The Aspect experiment, in other words, proves, beyond doubt that the quantum world, the world of the atom, is non-local. By non-locality, scientists mean that an entity is instantaneously affected not only by what is going on at one point - its locality - but also by what is going on at other places. Nevertheless, experimental proof exists. And this experimental proof at least hints at the existence of hidden variables to the extent that some scientists have picked up where Bohm left of and scientists like John Crammer have proposed theories that are akin to Bohm's hidden variables.

We will come back to Bohm and the hidden variables interpretation. First though, we will dedicate a chapter in an attempt to show the convergence of both cosmology and quantum.