“What Is Real? The Unfinished Quest for the Meaning of Quantum Physics” by Adam Becker

This book is about the controversies involved in the foundational knowledge of quantum physics. Quantum physics has been integral in developing such practical science as nuclear warheads and silicon transistors. Despite this, the very basic foundations of how and why quantum calculations actually work are still in dispute. In explaining the different theories still posited, Becker explains some of the basic science, the history behind various theories, the methods of various experimental setups, and why a clear conclusion has yet to emerge.

Most physicists subscribe to the Copenhagen Theory. “The Copenhagen interpretation states that quantum physics is merely a tool for calculating the probabilities of various outcomes of experiments…. Quantum physics proves that small objects simply do not exist in the same objectively real way as the objects in our everyday lives do.” It does not exist in the real world. Niels Bohr stated, “there is no quantum world. There is only an abstract quantum physical description.” Pascal Jordan continued, “the electron is forced to a decision. We compel it to assume a definite position; previously, it was, in general, neither here nor there…. We ourselves produce the results of measurement.” The measurement itself affects the outcome. The electron before was in a superposition, but the measurement interacted with it, it moved to a definite position. “Quantum physics uses infinite collections of numbers called wave functions to describe the world. These numbers are assigned to different locations: a number for every point in space…. The Schrodinger equation ensures that wave functions always change smoothly—the number that a wave function assigns to a particular location never hops instantly from 5 to 500. Instead, the numbers flow perfectly predictably: 5.1, 5.2, 5.3, and so on. A wave function’s numbers can go up and down again, like a wave—hence the name—but they’ll always undulate smoothly like waves too, never jerking around too crazily…. The wave function doesn’t tell you how much of the electron is in one place—it tells you the probability that the electron in in that place…. Once you find that electron, a funny thing happens to its wave function. Rather than following the Schrodinger equation like a good wave function, it collapses—it instantly becomes zero everywhere except in the place where you found the electron…. The Schrodinger equation holds all the time, except when you make a measurement.”

Heisenberg’s uncertainty principle stated that either you could know the location of an electron or how fast and in what direction it was going, but not both at once. “Heisenberg found a precise formulation of how much information you have to give up about an object’s momentum in order to learn more about its position, and vice versa. You could know a lot about where an object was or a lot about how it was moving—but you couldn’t know both at the same time.” Bohr added to the uncertainty principle the issue of complementarity. He stated, “any observation of atomic phenomena will involve an interaction with the agency of observation not to be neglected…. an independent reality in the ordinary physical sense can neither be ascribed to the phenomena nor to the agencies of observation.” Becker explains, “the quantum world could only be considered real in conjunction with some kind of measurement apparatus to study that world. And the behavior of the objects in that world, as indicated by such an apparatus, would be best described as either particles or waves, but never both simultaneously. These descriptions are contradictory—a particle has a definite location, which waves don’t.” Bohr did not view this as a problem, however. He stated, “we are not dealing with contradictory but with complementary pictures of the phenomena.” According to Copenhagen, this wave/particle duality is inherent in all quantum phenomena.

Within Copenhagen there was not complete consensus, but all the physicists agreed that it was pointless to talk about what was really happening in the macro world. Quantum physics was not a theory of the world as it actually is. It is a tool for making predictions. “Making accurate predictions about the outcomes of measurements was, for them, enough.” Bohr stated, “there is no quantum world. Isolated material particles are abstractions, their properties on the quantum theory being definable and observable only through their interaction with other systems.” Heisenberg stated, “the atoms or the elementary particles are not as real [as phenomena in daily life]; they form a world of potentialities rather than one of things or facts…. The idea of an objective real world whose smallest parts exist objectively in the same sense as stones or trees exist, independently of whether or not we observe them is impossible…. The transition from the ‘possible’ to the ‘actual’ takes place during the act of observation…. The transition from the ‘possible’ to the ‘actual’ takes place as soon as the interaction of the object with the measuring device, and thereby with the rest of the world, has come into play; it is not connected with the act of registration of the result by the mind of the observer.” John von Neumann threw his considerable weight behind the Copenhagen interpretation with a proof, which stated that wave functions normally obey the Schrodinger equation, but collapse upon measurement. Von Neumann stated, “we therefore have two fundamentally different types of interventions which can occur in a system. [When an object remains undisturbed, the equation] describes how the system changes continuously and causally in the course of time. [But once measurement is made] the arbitrary changes by measurement [are] discontinuous, non-causal, and instantaneously acting…. We must always divide the world into two parts, the one being the observed system, the other the observer. Quantum mechanics describes the events which occur in the observed portion of the world, so long as they do not interact with the observing portion, with the aid of the [Schrodinger equation], but as soon as such interaction occurs, i.e. a measurement, it requires the [collapse of the wave function].”

Einstein disagreed with the Copenhagen consensus. He felt, “the programmatic aim of all physics [was] the complete description of any (individual) real situation (as it supposedly exists irrespective of any act of observation or substantiation.)” His greatest problem with the Copenhagen interpretation was the issue of locality: “the principle that something that happens in one location can’t instantly influence an event that happens somewhere else.” He viewed the instantaneous wave function collapse as violating locality. Schrodinger brought to light the issue of entanglement. “When any two subatomic particles collide, they almost always become entangled. When a group of objects forms some larger object, like subatomic particles in an atom or atoms in a molecule, they become entangled. In fact, nearly any interaction between any particles would cause them to become entangled, sharing a single wave function…. For any entangled system, Einstein’s choice applied: either the system is nonlocal, or quantum physics can’t fully describe all the features of the system.”

David Bohm was the first man to come up with a counter interpretation that could explain the foundations of quantum physics. This was the Pilot Wave Theory. Becker relates, “particles have a wave nature, but there’s nothing “complementary” about it—particles are just particles, and their motions are guided by pilot waves. Particles surf along these waves, guided by the waves’ motion (hence the name). Heisenberg’s uncertainty principle still holds—the more we know about a particle’s position, the less we know about its momentum, and vice versa—but according to Bohm, this is simply a limitation on the information that the quantum world is willing to yield us. We may not know where a given electron is, but in Bohm’s universe, it’s always somewhere…. Bohm’s theory is mathematically equivalent to the Schrodinger equation, the central equation of quantum physics, and therefore it must make the same predictions as any other interpretation.”

The famous double-slit experiment showed the differences between Copenhagen and Bohm. Richard Feynman quipped that the double-slit experiment “has in it the heart of quantum mechanics…. In reality, it contains the only mystery.” Becker states, “the idea of particles, Copenhagen claims, is complementary to the idea of waves. The ideas are contradictory—photons cannot be both particles and waves…. When you aren’t measuring the position of a photon, it is a wave. Thus, photons can interfere with themselves as they pass through the double slit. But measuring the location of a photon forces it to behave as a particle: when the photon hits the screen behind the double slit, it must strike in only one spot.” Becker contrasts that explanation with Bohm’s theory, “photons, according to Bohm, are particles surfing on waves. While a particle can only pass through one slit, its pilot wave passes through both and interferes with itself. That self-interference, in turn, affects the motion of the particle, because it is guided by the wave…. Putting photon detectors on each slit affects each photon’s pilot wave—no matter how ingenious the design, any photon detector must alter a photon’s pilot wave, as ensured by Heisenberg’s uncertainty principle, which in Bohm’s interpretation places limits on how much measuring devices can avoid interfering with the things they attempt to measure…. In Bohm’s account, although measurement can influence a particle’s motion, all particles have definite positions whether or not anyone is looking at them…. In Bohm’s pilot wave interpretation, strange quantum behaviors are minimized for larger objects, which is why we don’t see them in the everyday world.” Bohm’s interpretation did away with the superpositions of electrons and was able to incorporate measurement devices into the quantum descriptions. However, it did not solve Einstein’s problem of nonlocality, “allowing particles to influence each other instantaneously at long distances. A single particle, wandering the universe on its own without bumping into anything, is guided in its path by its own pilot wave and is perfectly local. But introduce a second particle that interacts in any way with the first, and suddenly they are linked—entangled—and the pilot wave of one particle will change depending on the precise location of the other particle, no matter how distant it may be…. Because Bohm’s theory involved faster-than-light connections between particles, it appeared difficult to extend Bohm’s ideas to incorporate special relativity.”

Hugh Everett III was the next physicist to find the Copenhagen interpretation lacking. He took the measurement problem, that wave functions collapsed upon measurement, seriously. He understood that it placed any observer in a solipsistic position. Instead, Everett proposed a single universal wave function, “a massive mathematical object describing the quantum states of all objects in the entire universe. This universal wave function, according to Everett, obeyed the Schrodinger equation at all times, never collapsing, but splitting instead. Each experiment, each quantum event, spun off new branches of the universal wave function, creating a multitude of universes in which that one event had every possible outcome…. There is only one copy of you in each branch of the wave function, and, even if you repeat the experiment, this will still be true—there will be more branches, but each branch will still only have one copy of you. And the Schrodinger equation dictates that each branch will carry on independently of the others, with hardly any interaction between branches…. To each person in each branch on the universal wave function, their world appears to the the only world.” This was Everett’s Many-Worlds Theory.

John Bell was another Copenhagen heretic. He believed Von Neumann’s proof was incorrect. It purported to rule out any explanation of quantum physics that used hidden variables. “A hidden-variables interpretation assigns definite locations or other properties to quantum objects before they are observed, even if those properties can’t be calculated from the theory itself. These properties go unseen in the mathematics of quantum physics.” Bohm’s pilot wave interpretation is one such theory. Bell thought Einstein’s EPR paper, which questioned the locality of quantum physics, was another way around hidden variables. Bell tried to resolve the differences between Copenhagen, Bohm, and EPR. “The single wave function shared by the two entangled photons guarantees that they will always behave in the same manner when encountering two polarizers with matching axes…. Therefore, if nature is local, the wave function is not everything—there must be hidden variables. So either quantum physics is incomplete, or nature is nonlocal. We cannot have both locality and completeness in quantum physics…. So either the predictions of quantum physics are wrong and nature can be local, or quantum physics is right and “spooky action at a distance” is real.” Bell explained, “certain particular correlations, realizable according to quantum mechanics, are locally inexplicable, They cannot be explained, that is to say, without action at a distance.” This was Bell’s impossibility proof. “Bell’s theorem really leaves only three unequivocal possibilities: either nature is nonlocal in some way, or we live in branching multiple worlds despite appearances to the contrary, or quantum physics gives incorrect predictions about certain experimental setups.”

Dieter Zeh was the next quantum physicist to poke holes in the Copenhagen consensus. He independently came up with a Many-Worlds Theory, which in many ways resembled Everett’s. (Everett left academia for the Pentagon after barely receiving his PhD at Princeton after squabbles with Bohr, his thesis advisor, John Wheeler, and others at Bohr’s institute in Copenhagen and so his theory was promptly forgotten.) Zeh started by positing, “let’s assume that the universe is a closed system, like a nucleus.” Becker continues that Zeh’s “general idea, a system in a superposition, with its components strongly entangled—could explain how measurement works in quantum physics, without resorting to any of the tricks the Copenhagen interpretation used…. Quantum physics says that the measurement device will become strongly entangled with the thing it’s measuring…. The measuring device interacts with the experimenter, and everything else in the room, and eventually the entire universe—so when a small quantum system interacts strongly with a large object, ultimately, the entire universe ends up like Schrodinger’s cat, splitting into dead-cat and alive-cat “branches.” And the inhabitants of each branch of the universe only see one outcome…. The different branches of the universe are extraordinarily unlikely to interact.” Zeh explained, “the observer sees only one component [of the Schrodinger’s cat state] and not the superposition of all the others. So, that solves the measurement problem.” Bryce DeWitt added, “the universe is constantly splitting into a stupendous number of branches, all resulting from measurementlike interactions between its myriads of components. Moreover, every quantum transition taking place on every star, in every galaxy, in every remote corner of the universe is splitting our local world on earth into myriads of copies itself.” This interpretation, therefore, never requires any wave functions to collapse. It does require an almost infinite number of universes, however. We are actually living in a multiverse.

This Multi-Worlds interpretation was bolstered by the discoveries of String Theory and of the concept of inflation, which “says that the very early universe expanded extraordinarily quickly for a minuscule fraction of a second—increasing in size by a factor of about 100 trillion trillion in about a billionth of a trillionth of a trillionth of a second—then resumed expanding more slowly…. According to inflation, the universe is unable to escape “eternal inflation”: as inflation ends in one part of the universe, it continues in others, and “bubbles” of noninflating universe continually appear in the inflating region. We live in one of these bubbles; other bubbles would be their own universes, cut off from all others, and each might have its own laws of physics and assortment of fundamental particles. And because inflation is eternal, there would be an infinity of these bubbles—an infinite multiverse of inflation. String theory, meanwhile, doesn’t describe a single universe but instead describes a “string landscape,” a phenomenally huge number of possible universes—10^500 or more.”

Another possible interpretation is Information Theory. “If the wave function is information of some sort, rather than being a physical object, then many of the puzzles at the heart of quantum physics seem to melt away. In particular, the measurement problem seems much easier to explain if the wave function is information—your information changes when you make a measurement, so it’s no surprise that wave functions change dramatically when measurements occur…. [However] information-based interpretations of quantum physics ran the risk of collapsing into solipsism as well. If the information that the wave function represented was your information, what makes you so special?”

A final quantum interpretation is Spontaneous-Collapse Theory, which “manages to leave most of the predictions of standard quantum physics intact, while altering them enough to solve the measurement problem…. In Spontaneous-Collapse Theory, the quantum wave function is real, but it doesn’t obey the Schrodinger equation perfectly. Instead, sometimes the wave function collapses. But this collapse has nothing to do with observation or measurement—the collapse happens entirely at random, for no reason at all, whether or not anyone is looking…. Though a single-particle wave function might not collapse on average until a billion years have passed, the solid objects of our everyday lives…. are generally composed of at least 10 million billion billion individual particles. If each one of those particles’ wave functions is compulsively pulling the handle of its own slot machine, then, on average, at least one of them will hit the collapse jackpot every millionth of a second. But because the particles…. are all continually interacting with each other, they’re all entangled—which means they all share a single wave function…. As Bell put it, in Spontaneous-Collapse Theory, Schrodinger’s cat “is not both dead and alive for more than a split second.””

Quantum physics has enormous predictive power in the real world. The equations have yielded amazing advancements in science and technology. Therefore, it somewhat amazing that its basic foundations are still in dispute. Most physicists today believe in the Copenhagen interpretation. In graduate programs it is taught that Bohr was right and Einstein wrong. However, dissent has also grown. Today, the multi-worlds interpretation has garnered a few famous adherents, especially among those who still work specifically on the foundations of quantum theory. Perhaps one day a true consensus will truly develop.

“On the Aesthetic Education of Man” by Friedrich Schiller (translated by Keith Tribe)

Schiller felt that aesthetic appreciation led to an increase in moral behavior. In his view, living during the time of the French Revolution, he existed in a degenerate age. “Culture of the capacity for feeling is the more urgent need at this time, not merely because it will enable better insight into life, but because it prompts the improvement of such insight itself.” The artist had certain responsibilities. “Live with your century, but do not be its creature; serve your contemporaries, but give them what they need, not what they praise…. Chase from their pleasures all caprice, frivolity, and coarseness; so will you imperceptibly banish them from their actions, and finally from their convictions. Wherever you find them, surround them with refined, great, inspirational forms, encircle them with symbols of excellence, until appearance conquers reality, and art nature.”

Idealism, as philosophized by Kant, was the spirit of the day. Schiller combined these views with a practicality of living within the objective world. “Beauty conceived in reality in no way belies the concept we have already formed of it in speculation; only that, here in reality, it has much less freedom…. The man presented to beauty by experience is material already spoiled and recalcitrant, who robs it of so much of its ideal perfection when mixing it with his individual character…. It is man who transfers to beauty the imperfection of his individuality.” He next defines the aesthetic. “The soul thus moves from sensation to thought through an intermediate disposition in which sense and reason are both active…. If the condition of sensuous determination is called the physical, while the condition of rational determination is called the logical and moral, then this condition of real and active determinability has to be called the aesthetic.” However, aesthetics has its limits, “Beauty provides no single result for either intellect or will; it follows neither one single intellectual aim, nor any one moral purpose; it discovers not one truth, does not help us fulfill any special duty.”

Form, not the subject matter, is the purpose of true art. “The sublimity of a work of art can only consist in its close approximation to that ideal of aesthetic purity…. The work of the artist must overcome not only the limitations that the specific character of his art involves, but also those presented by the particular material with which he works. In a genuinely fine work of art the content should do nothing, the form everything; for it is form alone that has an impact on the whole man, while content affects only his individual powers. However exalted and comprehensive the content may be, it always has a limiting effect on the mind, and true aesthetic freedom is to be expected only from the form. This is the real artistic secret of the master, that he erases material with form.” In the end, it is the view of the subjective individual and not the object in actuality that can inform art “Only insofar as appearance is sincere (expressly abjuring all claim to reality), and only insofar as it is autonomous (renouncing all support from reality), is appearance aesthetic…. It is incidentally not at all necessary that the thing in which we discover beautiful appearance is without reality, if only our judgment of this thing takes no account of this reality.”

“The Birth of Tragedy by Friedrich Nietzsche (translated by Shaun Whiteside)

In his first book, Nietzsche details the role of Greek tragedy in forming humanity’s conception of aesthetics. “Art derives its continuous development from the duality of the Apolline and Dionysiac…. To the two gods of art, Apollo and Dionysus, we owe our recognition that in the Greek world there is a tremendous opposition, as regards both origins and aims, between the Appolline art of the sculptor and the non-visual, Dionysiac art of music. These two very different tendencies walk side by side, usually in violent opposition to one another…. By a metaphysical miracle of the Hellenic ‘will’, the two seem to be coupled, and in this coupling they seem at last to beget the work of art that is as Dionysiac as it is Appoline— Attic tragedy.”

First, Nietzsche zooms out to convey how aesthetics relate to reality. “We can indeed assume for our own part that we are images and artistic projections for the true creator of that world, and that our highest dignity lies in the meaning of works of art—for it is only as an aesthetic phenomenon that existence and the world are eternally justified…. Only in so far as the genius is fused with the primal artist of the world in the act of artistic creation does he know anything of the eternal essence of art.”

Nietzsche describes, in minute detail, the composition and meaning of Attic tragedy, as it was first performed in Athens, “The ground walked upon by the Greek satyr chorus, the chorus of the original tragedy, is an ideal ground, a ground lifted high above the real paths of mortal men. For this chorus the Greeks built the floating scaffold of an invented natural state, and placed upon it natural beings invented especially for it. It was on this foundation that tragedy arose…. The satyr, the Dionysiac chorist, lives in a world granted existence under the religious sanction of myth and ritual….

The satyr, like the idyllic shepherd of our own more recent age, is the product of a longing for the primal and the natural; but how firmly and fearlessly did the Greeks hold onto this man of the woods…. Nature, still unaffected by knowledge, the bolts of culture still unforced—that is what the Greeks saw in their satyr…. He was the archetype of man, the expression of his highest and most intense emotions, an inspired reveler enraptured by the closeness of his god…. The chorus is a living wall against encroaching reality because it—the satyr chorus—depicts existence more truly, more authentically, more completely than the man of culture who sees himself as the sole reality…. The contrast between this authentic, natural truth and the lie of culture masquerading, as the sole reality is like the contrast between the eternal core of things, the thing in itself, and the entire world of phenomena…. The symbolism of the satyr chorus analogously expresses the primal relationship between the thing in itself and the world of appearances….

This interpretation perfectly explains the chorus in Greek tragedy, the symbol of the crowd in a Dionysiac state…. The tragic chorus of the Greeks is older, more primordial, indeed more important than the ‘action’ itself…. We now know that the stage, and the action, were fundamentally and originally conceived only as a vision, that the sole ‘reality’ is the chorus, which generates the vision from within itself…. In its vision this chorus beholds its Lord and master, Dionysus, and hence it is always a chorus of votaries…. In this function of complete devotion to the god, it is the supreme, Dionysiac expression of nature, and therefore, like nature, it speaks under the spell of wise and oracular sayings. Sharing his suffering, it is also wise, heralding the truth from the very heart of the world…. 

This is the Apolline dream state, in which the daylight world is veiled and a new world, more distinct, comprehensible and affecting than the other and yet more shadowy, is constantly reborn before our eyes…. The language, colour, mobility and dynamic of speech become completely separate spheres of expression in the Dionysiac lyric of the chorus and the Apolline dream world of the stage. Everything that comes to the surface in the Apolline part of Greek tragedy, the dialogue, looks simple, transparent and beautiful.”

Finally, Nietzsche concludes by revealing the role myth and tragedy played in shaping our culture at large, “Without myth all culture loses its healthy and natural creative power: only a horizon surrounded by myths can unify an entire cultural movement. Myth alone rescues all the powers of imagination and the Apolline dream from their aimless wanderings. The images of myth must be the daemonic guardians, omnipresent and unnoticed, which protect the growth of the young mind, and guide man’s interpretation of his life and struggles. The state itself has no unwritten laws more powerful than the mythical foundation that guarantees its connection with religion and its growth out of mythical representations.”

“The Dehumanization of Art and Other Essays” by Jose Ortega y Gasset (translated by Helene Weyl et al.)

Ortega y Gasset, never a wholehearted fan of modernity, nevertheless reluctantly concedes the value of modern art. As usual, he gives a characteristic patrician twist, perhaps not intended by the artists themselves, ““From a sociological point of view” the characteristic feature of the new art is, in my judgment, that it divides the public into the two classes of those who understand it, and those who do not…. Hence the indignation it arouses in the masses. When a man dislikes a work of art, but understands it, he feels superior to it; and there is no reason for indignation. But when his dislike is due to his failure to understand, he feels vaguely humiliated…. The art of the young compels the average citizen to realize that he is just this—the average citizen, a creature incapable of receiving the sacrament of art, blind and deaf to pure beauty…. The time must come in which society, from politics to art, reorganizes itself into two orders or ranks: the illustrious and the vulgar.”

The dehumanization of the subject and processes of art is, for Ortega y Gasset, modern art’s defining characteristic. “When we seek to ascertain the most general and most characteristic feature of modern artistic production we come upon the tendency to dehumanize art…. Far from going more or less clumsily toward reality, the artist is seen going against it. He is brazenly set on deforming reality, shattering its human aspect, dehumanizing it.” The other characteristic is for art not to take itself too seriously. “To insist on neat distinctions is a symptom of mental honesty. Life is one thing, art is another…. The first consequence of the retreat of art upon itself is a ban on all pathos. Art laden with “humanity” had become as weighty as life itself…. To look for fiction as fiction—which, we have said, modern art does—is a proposition that cannot be executed except with one’s tongue in one’s cheek. Art is appreciated precisely because it is recognized as a farce…. The new art ridicules art itself…. Art has no right to exist if, content to reproduce reality, it uselessly duplicates it. Its mission is to conjure up imaginary worlds. That can be done only if the artist repudiates reality and by this act places himself above it. Being an artist means ceasing to take seriously that very serious person we are when we are not an artist.”

Finally, Ortega y Gasset posits a purpose of modern art, “Were art to redeem man, it could do so only by saving him from the seriousness of life and restoring him to an unexpected boyishness…. All modern art begins to appear comprehensible and in a way great when it is interpreted as an attempt to instill a youthfulness into an ancient world.”

“The Plains” by Gerald Murnane

The most famous of Murnane’s novels, “The Plains” is a strange book. The novel’s narrator is a filmmaker, an outsider from Outer Australia, hired by one of the patrons of the Great Houses of the plains to live amongst them, to soak in their way of life, to study, and to create art. “The plainsmen were not always opposed to borrowings and importations, but in the matter of culture they had come to scorn the seeming barbarisms of their neighbours in the coastal cities and damp ranges.” The people of the plains have unique ways about them and a mythic quality. “They seemed to know what most men only guess at. Somewhere among the swaying grasses of their estates, or in the least-visited rooms of their rambling homesteads, they had learned the trues stories of their lives and known the men they might have been.” The story contains embedded within it a rivalry between two sects of plainsmen- the Horizonites and the Haresmen. “Almost any duality that occurred to a plainsman seemed easier to grasp if the two entities were associated with the two hues, blue-green and faded gold.” There is also much socializing, drinking, philosophizing, and debating. “In moods like this I suspect that every man may be traveling towards the heart of some remote private plain.” And most of all, there is a lot of looking at and contemplation about the greatness of the plains. “The plains are not what many plainsmen take them for. They are not, that is, a vast theatre that adds significance to the events enacted within it. Nor are they an immense field for explorers of every kind. They are simply a convenient source of metaphors for those who know that men invent their own meanings.”