What is Real?: The Unfinished Quest for the Meaning of Quantum Physics Paperback – January 1, 2018

This book is worth while as there is some interesting history presented and is well written and researched. However, the author’s main underlying purpose is to argue for pilot-wave and/or many-worlds interpretations of quantum mechanics (QM), and to argue against the Copenhagen Interpretation (C.I.). Unfortunately, his obvious bias prevents him from articulating fairly what the C.I. actually was or why it existed,… even implying it was incoherent and adopted en masse due to some conspiracy of personalities, particularly Niels Bohr.This is questionable to say the least as it's not actually confusing as to why the C.I. was adopted en masse; As pointed out to E. Schrodinger at the time, the wavefunction can not be an observable physical entity as he envisioned it, as it evolves in a tensor product space. Therefore, it is quite rational why one would adopt a Born Rule type interpretation of the wavefunction. Both the Born Rule component of the C.I. and the "shut up and calculate" component merely reflects how actual QM experiments must occur. The former on account of the fact that there is only one measurement result despite a possible superposition of states as described via the wavefuncion, and the latter on account of the fact that no one can actually have a wavefunction description of himself and the experimental apparatus. Another rational reason why the C.I. was adopted en masse, was that the standard Hilbert space mathematical foundation of QM with von Neumann's projection postulate (wavefunction collapse) was able to unify both the matrix mechanics of Heisenberg and the wave formulation of Schrodinger. Certainly a general scientific positivist mentality was a great influence in motivating C.I. at the time as well.... as it should have."I can well appreciate that, in the early days of quantum mechanics, something of the nature of Niels Bohr's perspective on the subject was almost a necessity, so that the theory could actually be used, and progress in quantum physics could be made" - Roger PenroseThe author briefly mentions twice that Bohr was influenced by Kant, but remarkably never attempts to explain Kant’s epistemology.Considering Bohr’s interpretational contributions to quantum theory, Abraham Pais, nuclear physicist and renowned biographer and physics historian, stated that Bohr was “one of the most important twentieth century philosophers,…. As such he must be considered the successor to [Immanuel] Kant,…”.Essentially, the C.I. argument was that the measurement problem is epistemic in nature, and therefore not a problem with the theory itself. In other words, the discontinuity between the deterministic evolution of the wavefunction via the Schrodinger equation, and the “collapse” to a measurement result, is on account of the conditions of observability given the nature of mind. Which is to say, we must supply a conceptual form in which the ‘underlying reality’ is to be observed in the first place. In the standard Hilbert space formulation of QM, the Operator and Basis are supplied by the physicist given the particular experimental arrangement and interpretation of results. So, if one is so inclined to imagine a de facto metaphysical ‘underlying reality’, one can see that this supposed reality is projected or conformed to, our a-priori conceptual framework, in order to meet the conditions of observability…. by a mind so constituted, given its evolution to synthesize experience on the macroscopic scale…. i.e. "it" is only a particle or a wave to the extent that those notions are defined by the experimental apparatus and interpretations thereof.And no, an epistemic interpretation does not mean that consciousness ‘reaches out’ as it were and interacts physically with the quantum system to cause collapse of the supposed physical wavefunction. There was some historical confusion on this point. We’re talking about a biological system evolved at the macroscopic scale with it’s own emergent laws, processing experience to form a synthesis for the understanding, which since this mind is NOT omnipotent, must of necessity have conditions for observability to be at all possible. This precludes knowledge of ‘independent reality’ because intellectual artifacts or 'conceptual forms of thought' are always implicit in the experimental arrangement, presumptions, and interpretations....“There is no way to remove the observer — us — from our perception of the world, which is created through our sensory processing and through the way we think and reason. Our perception — and hence the observations upon which our theories are based — is not direct, but rather is shaped by a kind of lens, the interpretive structure of our brains.”- Stephen Hawking“The doctrine that the world is made up of objects whose existence is independent of human consciousness [mind] turns out to be in conflict with quantum mechanics and with facts established by experiment." - Bernard d'EspagnatThe author does not state that the pilot-wave for multiple particles, evolves in a tensor product space, which is to say not in our 3 dimensional space, and therefore is in principal unobservable. Likewise, the many-worlds are in principal unobservable. Despite suggestions to the contrary in the book, this is entirely different from Mach’s view that atoms are metaphysical on account of not observing them,… as in principal, atoms could be observed or rationally hypothesized given observable attributes. Metaphysical entities are precisely those that are intrinsically unobservable, like the pilot-wave or multiverse. In contrast, an epistemic interpretation does not propose unscientific metaphysics, but rather artifacts of thought, which IS in principal investigable as the field of epistemology. It’s just that the problem extends beyond physics, and into a field that is undeveloped. See “John von Neumann’s Cut” to substantiate this point.Since all interpretations of QM are empirically indistinguishable, it becomes a Choice of the theoretician which is to be his guide,… and therefore are epistemic in any case.I don’t feel that the author presents the interpretation of the Bell inequality tests entirely fairly; The empirical failure of the Bell inequalities refutes ‘local realism’, by which is meant that at least one of the following implicit assumptions are refuted,… locality, counterfactual definiteness [Stapp, Eberhard], or no conspiracy condition. The Copenhagen Interpretation was philosophically aligned with the rejection of counterfactual definiteness, …i.e. that elements of reality or attribute values exist independently of measurement,… or more properly, that for statistical purposes it is valid to presume measurements that could be, but have not been performed (this would have been rejected by C.I.). The author seems to imply that no such assumption is made in the Bell tests, despite that it is the very point of the Bell tests to presume this,…. resulting in the conclusion that no such classical presumptions of hidden variables can reproduce the results of quantum mechanics, given Einstein locality. The generalized Bell theorem, however, makes no assumptions with respect to the form of the quantum entity or attributes being measured (particle, wave, spin, polarization, position, momentum, etc).The author is correct to say that philosophy is important in physics as at minimum a guide for theoretical research and interpretation of results. The author is also correct to point out Quine’s thesis that verification or falsification can not be done in isolation, free and clear of any presumptions and interpretations, thus refuting the extremism of logical positivism. However, Quine did not refute scientific positivism nor verification nor falsification as valid and essential guides for physicists,….. as if he managed to crack the door open such that it was then legitimate for metaphysics to infect science. The many-worlds formulation is itself an extremism of mathematical idealism, in that it essentially lets the mathematics of the wavefunction solutions of the Schrödinger equation supplant the work of the theoretician."As far as laws of mathematics refer to reality, they are not certain; and as far as they are certain, they do not refer to reality" - A. EinsteinNot mentioned in the book as well is that the C.I. has since been revised with decoherence, in the consistent histories interpretation,… “Copenhagen done right”.A few general-reader books by prominent physicists that speak out against metaphysical speculation in physics and cosmology are,...-The Trouble With Physics: The Rise of String Theory, The Fall of a Science, and What Comes Next - Lee Smolin-Fashion, Faith, and Fantasy in the New Physics of the Universe - Roger PenroseAn excellent and fairly unbiased exposition of the various interpretations of QM....Beyond Measure - Jim Baggott

This volume is the single best explication to the general reader of the historical progression of foundational issues in QM that has ever been written.In addition---1. The author really understands the measurement problem.2. The author really understands what Einstein's criticisms were and they were NOT about randomness.3. The author really acknowledges that Bohr was spewing out inane baloney from the early 20's onward.It is impossible to cover all foundational issues in depth in 300 pages, but the author covers everyone from Einstein, Bohr, Schrodinger, Heisenberg, de Broglie through Bohm, Everett, Bell, Clauser, Aspect, GRW, Zeh and beyond.What sets this volume apart from other surveys is the author's grasp on the key differences in interpretational issues, e.g. something as simple as the difference between 'incomplete' and 'inaccurate' or as complex as locality+incompleteness vs non-locality+(maybe)completeness.I could go on and on but why waste any more of your time. Just go and buy it.FIVE STARS

This book is very timely. With many Physicists opening the door to Quantum Foundational issues and wanting to know the true underlying reality, not content with merely shutting up and calculating, this book will be a supplement in any library concerning the history of Quantum Physics and the so called dissidents of the Copenhagen Interpretation mainly in David Bohm's Pilot-Wave Theory and Everett's Many-Worlds Interpretation but also though smaller GRW, in addition too as well John S. Bell.Part I: This was a good start concerning the Copenhagen Interpretation and its founders. Also early dissidents like Einstein and Schrödinger. I think this book is very lay friendly and easy to follow along concerning the theory and early issues with it. You also find that there really was no singular Copenhagen Interpretation despite Heisenberg giving them a singular label. Also you start to see how politics and social issues really helped launch Copenhagen. I learned how charismatic Bohr was yet how his very own students said he had issues with comprehension but also how vague he was and how people like Heisenberg despite not being a Nazi supported Nazi Germany (indeed Pascual himself was a Nazi), you see how bad Heisenberg was with experimental physics despite his somewhat confidence in German physics above others. Einstein by contrast to these men took on no students as Bohr, as he wasn't as charismatic and though spoke well, sometimes he was misunderstood such as in the case with Bohr or the when others wrote on his behalf but not in as clear a way as he would have, he also wrote longer statements than say Bell and he helped the U.S. in the Nuclear Race.Part II: This is where the major dissidents who made rival theories to Copenhagen appear but also others like Bell who advanced the conversation and gave scathing critics. These include mainly David Bohm and Hugh Everett. You find just how exiled Bohm was mainly for his communist affiliation but also for going against the status quo in the Copenhagen Interpretation. Also how Everett was with his prankster style yet sort of nonchalant attitude (interestingly you learn that Wheeler would try to help him get it out there and that Everett never cared to be an Academic but was content as a Cold War technocrat). Bohm would later abandon Communism but also his own Interpretation due to these many factors.Part III: Here is where the story continues and the next generations picked up where the former one's left off. You get to see how Bohm picked up his own Theory and revived it again thanks to Basil Hiley and some students. And others who advanced the Many-Worlds Interpretation of Everett as well. Moreover many others who advanced Bell's inequalities via experiment. This chapter was very helpful as many of these figures are hardly as known to a more lay audience such as Dieter Zeh and John Clauser and others. Very informative. Also GRW Theory makes an appearance along with David Albert.You see throughout this book how changes due to Social and Political issues affected many of these men, some not even having a job despite their importance in these Foundational Issues and how many did not give them a chance but in the end they made an impact unto today.I also found Adam Becker's comments on Philosophy to be extremely needed and he rightly went against the notion that Philosophy is dead or of lesser importance but it is precisely these historical and social issues that pushed this wrong idea of Philosophy it seems into Academia to the chagrin of people like Einstein who held it in high esteem. This was a pleasant suprise to me. The issues concerning the "Shut up and Calculate!" approach he also addresses as problematic which I was very pleased with as well.The last part an Appendix was concerning how these different Theories (including GRW) solve the Delayed-Choice experiment which is a very much discussed topic at least to a more lay audience and was very glad to see it included.The only 2 minor problems I had with the book is that a lot of the stuff on Nazi Germany seemed to not be important concerning the history of these realist dissident interpreations. However it was still very fascinating and had very import things in it still, like how this War affected the Physics community and to learn more concerning the personal lives of these men who are often adored. The last issue was the footnotes. Since the book itself doesn't give you an inserted number reference in the text as you are reading it makes it hard to know if you need to check for one. I practically even forgot about them throughout the book however he does give a ton of references to practically everything in there which is extremely helpful.Despite these small gripes, this is a book certainly needed. If you don't have it, make sure to add it to your collection, it is a must have.

You really need to know the physics already before you read this book, or you will get mislead by the biased and oversimplified descriptions of the few experiments that are presented. You would also be confused after the almost non-stop bashing of the Copenhagen Interpretation why it has continued to hold such sway. What the book does do very well though is describe the historical and philosophical background of the CI, Pilot Wave and Many Worlds interpretations. Becker does make a good argument why philosophy should be given greater emphasis in modern education.The book is very enjoyable to read if you just set aside the rants on CI and enjoy the philosophical connections that are made.

This book, written in a popular style, gives the history of how physics has taken a wrong turn for over 80 years. For centuries, since about 1600, scientists had regarded it as their vocation to study the universe and describe mathematically how it and its contents behave and interact. In effect they were confident that, even if the whole of humanity were obliterated, the universe would continue to exist, obeying the same laws.At the outset of the twentieth century scientists investigating the microphysics of the world found that they were no longer able to understand the universe in this fashion. Quantum mechanics (QM), the best mathematical formalism available, was complicated and ad-hoc. It was superb in predicting the results of laboratory experiments (to many decimal places) – but attempting to discover the reality behind these results seemed to force one into paradox.It was here that the appalling mistake was made. From about 1927, under the leadership of charismatic Niels Bohr, a prominent group of physicists (the ‘Copenhagen’ school) insisted that the failure of understanding of that era was to be elevated into an eternal principle: the microphysical could only ever be understood in terms of laboratory experiments. Outside of this piddlingly limited context, we could never know anything. By making this grandiose (metaphysical) claim of eternal ignorance, these physicists abandoned the quest to understand the realities of the universe – some denied that there were any. Worse, this powerful group did their utmost to ensure that anyone who had the temerity to try to understand the micro-world was subject to personal abuse, to having their arguments ignored and their careers ruined. The book describes the history of this dominant group and those who dissented from them: how the latter were misrepresented – and still are to this day.Einstein, together with colleagues Podolski and Rosen (EPR), described a simple physics experiment, and agreed that QM correctly predicted its results. But what followed from these results? EPR carefully and explicitly (1) set out a sufficient condition for an objective (real) physical property to exist and (2) defined a locality condition stating that the universe is such that systems are isolated from one another if they are space-like separated. EPR began by supposing that the universe satisfied this locality property. The experiment and its (undisputed) results then implied that subatomic particles must have real physical properties which determine both their position and momentum simultaneously; moreover these physical properties must be deterministic. EPR concluded that – if one accepts the locality condition – then QM must be incomplete and in need of supplementing by deterministic hidden physical properties. Bohr’s response was a model of obscurity, and there is still no consensus as to what he was trying to convey.David Bohm arrived at a straightforwardly realistic model of the world in which particles have definite positions and velocities at all times. A feature of this theory is that it is explicitly non-local. The experimental predictions of this theory are identical to those of QM. When someone presented Bohm’s model at a seminar in Princeton his ideas were rejected as “juvenile deviationism”, he was denounced as a Trotskyite, and Oppenheimer closed the meeting by suggesting that “if we cannot disprove Bohm, then we must agree to ignore him”.John Stewart Bell took up EPR’s ideas and developed them so that they became experimentally testable. He showed that, if locality is true, then the experimental results on two isolated systems (involving particles originating from a common source) must satisfy a certain inequality – Bell’s inequality. Clauser was first to test this and Aspect later performed an improved experiment in which the choice of experimental arrangement in each of the target locations was not made until after the particles had left the source. Both experiments violated the Bell inequality, demonstrating that our universe is non-local.Even today quantum mechanics is mistaught and false assertions made – even at the most prestigious universities. Here are just some of the myths about the Aspect experiment:1) Einstein rejected QM and its experimental results because he was wedded to determinism. Einstein accepted all the result of QM – it was the irrealism and vagueness of Copenhagen QM that he objected to. Determinism for some physical properties is a logical consequence of accepting locality as the EPR paper shows.2) The Aspect experiment proves that no deterministic account can be given of microphysical behaviour. This is false as Bohm’s model shows.3) The Aspect experiment proves that QM gives a complete picture of the universe. This is false as Bohm’s model shows.4) Einstein was mistaken in assuming that the universe is local. This is technically true but highly misleading. Einstein was the first to see that Copenhagen QM implied that the world was non-local. He explicitly put locality into the EPR paper as a hypothesis. It is perfectly honourable for a scientist to make a plausible, explicit, testable proposal that is later shown to be wrong. By these standards Bohr’s response to EPR was “not even wrong.”5) The Aspect experiment’s proof of non-locality was predicted by and thus vindicated Copenhagen QM. In fact, nonlocality (under the name “entanglement”) was first discussed by Schrödinger, a critic of the Copenhagen school. Its experimental discovery was the joint work of Copenhagen dissidents EPR, Bell, Clauser and Aspect. This, the most bizarre feature of the quantum world, was initially greeted with astonishment, but almost immediately accepted (one might say purloined) with complacency by Bohr and company.The later part of the book describes how new and realistic versions of QM are coming into acceptance – at least as *respectable candidates* for rationally describing the world as it actually is. Any realistic QM must describe micro- and macro-entities in the same terms, obeying the same laws. Ghirardi, Rimini and Weber (GRW) have developed a stochastic “spontaneous collapse” model in which, as with the case of Bohm, the macroscopic world of commonplace objects arises smoothly and in an understandable manner from the quantum subatomic world. GRW’s predictions differ very slightly from QM, but no experimental test has so far been proposed that would distinguish them. Everett’s “Many Worlds” interpretation is popular, especially among cosmologists. This still has a major problem in that experimental probabilities cannot be derived in a principled way from the alleged splitting of the universe. (My suspicion is that, because of this lack, “Many Worlds” will not prove to be tenable as a description of reality.)This is an excellent popular-science book. It certainly won’t teach QM, but it makes one realise the extent to which lowness of nature stalks the jungles of academe. It is very well referenced; perhaps most valuable are interviews with various scientists, some conducted by the author. This book introduces the hero of realism John Stuart Bell to a general audience. He is a wonderful, underrated scientist and philosopher whose papers are witty – in the senses of being down-to-earth, erudite, apt and also laugh-’til-it-hurts funny.

A solid overview of the problems in the quantum foundations (via a historical approach), from a pluralistic perspective. The author takes the reader on a fascinating journey from the beginnings of QM until our days, covering the most important events in the evolution of our understanding of QM, including some crucial developments in the philosophy of science relevant to the subject (the problems with the old positivism of Mach, the fall of logical positivism and the rise of realism, the problems with falsificationism in front of Duhem-Quine criticism and so on), finally explaining well why the current generation of physicists hold philosophy in low esteem and how they are wrong.I liked the clarity of the explanations, I read quite many books on QM before and I witness I was surprised by the simplicity of the descriptions and analogies used, very easy to understand even for people who know relatively few things on the subject. In short an easy to read book but which offers nonetheless a solid understanding of the subject [here I mean the foundational aspects of quantum mechanics, by the way the author never claim to teach the formalism of quantum mechanics]. Sure there is not a great depth but it is more than enough to have a clear overview of the facts (for example the fact that the author does not stress that Bohr tried to undermine the definition of what constitute an element of reality in EPR paper changes little)..Anyone who has not decided yet (entirely subjectively I would say) that Science can only be cumulative (at least at limit) or that we already have clear cut criterions to make a difference, once and forever, between Science and pseudo-Science will be sympathetic with the approach of Becker. I certainly am. Without falling in (quasi)relativism though, too much postmodernism is harmful despite the undeniable social dimension of the scientific quest (but Becker is not guilty of that).Finally, to paraphrase Popper if I am not wrong, 'if we are told again and again that something is impossible or meaningless even the most obvious connections may go unnoticed'. Let's not be too authoritarian here, what if a (contextual) nonlocal realist 'hidden variables' theory is there, waiting to be discovered (giving us at least a glimpse of reality at quantum level)? Even superdeterminism is still viable I'd say, anyways counterfactual definiteness should not be a 'sacred cow', in spite of the fact that is of 'bon sens' to accept it (I agree that physicists are entitled to use it in the assumptions; as much as a healthy fallibilism is still there of course).Now one can argue that not all existing interpretations of QM are on equal foot if we look beyond the mere empirical aspect (albeit all have problems) but I don't think this is enough to claim that there is a winner at this time (as some would like, usually arguing pro Copenhagen); no interpretation has the important edge which to make it irresistible from a rational standpoint (maybe in the future). Besides we must never forget that even seemingly degenerative research programs can, sometimes, become extremely successful later, when the 'background assumptions' are prepared for them. Fallibilism should always be there. Becker's approach is definitely sound.

A somewhat polemical account of the Quantum Interpretation Wars of the 20th century (and since). Bohr plays the villain, Einstein and Bohm the misunderstood heroes.What does Quantum Mechanics tell us about the nature of reality - is the wavefunction "real" or is it just a useful mathematical model of something more fundamental? Can we know and does it matter?It's nice to see these questions coming back into vogue, after having been dismissed as an unnecessary or unproductive avenue for a while. I think the lack of a convincing explanation for why QM allows us to predict the behaviour of the subatomic world (albeit only probabilistically) is a clear sign that it is an unfinished theory.This book isn't really trying to answer the question that the title poses, but it does want to challenge the idea that Bohr won the debate, or that the question is not worth asking.

This is probably the most accessible telling of the quantum story I have come across, & certainly one of the most engaging & useful. The author discusses his whole subject with us, & reading it a chapter at a time (as I did) is like attending a high quality evening class. Having just finished it, I could write reams more appreciation, but perhaps I had better just say it's a landmark, & recommend you enjoy it for yourself.

This book looks in detail at the interpretation of quantum mechanics, a topic often ignored by standard quantum mechanics texts. It takes issue with the Copenhagen Interpretation still adhered to by many physicists. It deals with many of the alternatives-many worlds, pilot waves etc in a thorough, though non-mathematical way. I think it would be a worthwhile read for both professional physicists and for students who wish to delve deeper than equations of a standard textbook. The book is, at times, a little too partisan for my taste. Supporters of Copenhagen are clearly villains, whereas it’s opponents are noble seekers of the truth. However, I enjoyed the book and would recommend as a challenging and provocative read.