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AJM Book Talk: “What Is Real?” by Adam Becker

Ruminating about Adam Becker’s book about quantum physics and the debate over the nature of reality

Physics Professor Niels Bohr
Niels Bohr, legendary physicist and, in some ways, the antagonist of Adam Becker’s “What Is Real?”

I recently finished “What is Real?” by Adam Becker, and it is a book that I’ve not stopped thinking about after reading it. It deals with quantum physics and the nature of reality, a topic I’m fascinated with, but which I realize many people don’t find interesting, so I get it if you close the browser or otherwise move on to something else after reading this sentence. But I have a tendency to want to write about things I’ve been thinking about a lot, and I have this here blog, and there’s not much baseball going on, so...

“What is Real?” came out in 2018, when Becker was 34, and was written as a result of him getting a Sloan Foundation grant a couple of years earlier to “research and write a book on the history of the foundations of quantum physics, with a particular emphasis on the continued dominance of the troubled ‘Copenhagen Interpretation’.” The fact that grant summary calls it the “troubled” Copenhagen Interpretation provides a pretty clear hint at the direction which Becker is coming from, something I wasn’t aware of when I was reading the book, but which became clear pretty quickly.

Becker has an interesting academic background — he got his B.A. from Cornell in Physics and in Philosophy in 2006, got a masters a year later from the University of Michigan in Physics, and then got a Ph.D. from UofM in Computational Cosmology in 2012. He’s done a lot of writing and teaching, and is currently at the Lawrence Berkeley National Laboratory in a position he describes on his website as being “Science Writer and Communications Specialist,” and describes himself as “Author and Astrophysicist.”

Before I really dive into this, I want to talk a little bit about my dad (and if you’re just interested in Becker’s book and quantum physics you can skip the next several paragraphs and resume reading after the * * * ). As many of you know, he’s a veterinarian who has a clinic and, as of several years ago, a no-kill animal shelter in southwest Fort Worth. He’s had his own veterinary clinic for almost 50 years.

He was also the first person in the family to go to college. He grew up in a working class family, as that term was understood in the early and middle parts of the 20th century, the oldest of three children. His father — my grandfather — worked for the railroad, was in the union, and had the type of nice, steady job that was much more commonplace back then than it is now, the type of job that is romanticized is some quarters and decried as wage slavery in others. My grandfather worked hard at a job that, as best as I can tell, he didn’t particularly care for, but which he had to do in order to provide for his wife and children.

One of the things that my dad has always talked about, for as far back as I can remember, was that when he was a kid, when he was growing up, he looked at the life his father had, the life others in the neighborhood had, and said to himself, I’m not going to live like this. I’m not going to work every day for someone else doing a job that I don’t really want to do in order to just scrape by. He was adamant he was not going to live his life that way.

Unlike his eldest son, my father has always had tremendous drive and a great work ethic. He started working at an early age, always had a job from his adolescence, often times more than one. He got up early in the morning throughout his teenage years to throw papers. One of his jobs was working behind the counter at Swenson’s Ice Cream — for whatever reason, that’s one of the ones that really sticks in my mind.

And while he was doing this, he always got very good grades in school. Again, unlike his eldest son, he had the willpower and drive to pay attention, get his schoolwork done, and put in the effort and the work to get good grades. He did well enough in high school to get into Texas A&M University, which he (and my mom, when they got married after his freshman year) worked to put himself through, both undergrad and vet school.

All through school, elementary, middle and high school, then undergrad and graduate school, he says he only made one “C.” And that was in Physics. My niece, who is currently at A&M seeking to follow in his footsteps and go to vet school (she’s currently an undergrad), was talking to us about that part of the family lore over Christmas, and how that’s also the thing that she has the most problems with. Biology, both of them really enjoyed and understood and were good at. Chemistry was, for both of them, something they could handle, but was a strong suit. Physics, though, was her biggest hurdle, just like with her grandfather.

I thought that was interesting because for me it is the exact opposite. I have never understood biology. I have never been good at it. I struggled with it in school, and still have a hard time grokking it. On the other hand, physics — THAT I get. I can process it. I was always good at it in school, both high school and college. Its something I’m fascinated by, and enjoy reading about.

As I was explaining that in our discussion, my dad turned to my niece and said, “Well of course he likes physics. He loves all that math. I don’t want to deal with all that math. I want to deal with what’s alive, with what’s REAL.”

* * *

You can draw a line, if you want, between biology and physics, with biology dealing with what the real, physics with the abstract, and chemistry straddling the line, having a connection to both. During the Enlightenment, there wasn’t so much of this schism — there were simply Natural Philosophers, exemplified by the Royal Society, who sought to understand nature, in whatever form. But as our understanding of nature, of the world, of the universe surrounding us increased, the breadth and depth of knowledge made it harder to keep up (Albert Einstein famously said that Johann Goethe, who died almost 200 years ago, was “the last man in the world to know everything”), and resulted in ever greater degrees of separation and specialization of the sciences.

But part of what I find so fascinating about physics is that, contrary to what my dad said, it is about what’s real. Yes, I do like and grok math more than...whatever it is you need to like and grok to get biology, but I hit a wall at Calculus II, and am not going to pretend I have any sort of detailed knowledge or understanding of the level of math necessary to do high level physics. But on a fundamental level, what makes it so gripping is that it is about understanding — or trying to understand — how Everything — with a capital E — works.

And with quantum physics, part of what makes it so fascinating is how bizarre and non-intuitive reality is — or at least how we perceive reality. Becker, examining the past century of work in quantum physics, ends up delving into the meta-issue of, what does it mean to understand how Everything works?

As is inherent in any examination of the history of quantum physics, Niels Bohr is a major figure in the book, and while Becker says (in response to a negative review of “What Is Real?”) that he doesn’t think he “paint[s] Bohr as a villain,” he does come across to me as, at least, the antagonist. The breakthroughs Bohr and Werner Heisenberg made in the 1920s in taking the findings and theories that Max Planck, Albert Einstein and others made in the first quarter of the 20th century and using it to build mathematical models that reflected the observational data led to what is known as the “Copenhagen Interpretation.”* It is the Copenhagen Interpretation that Becker spends much of the book assailing, and as Bohr is the godfather of the Copenhagen Interpretation, it ends up coming across as challenging — or, less charitably, attacking — Bohr.

* The term “Copenhagen Interpretation” was not used at the time — it appears to have been coined at some point in the 1950s — but its use became widespread. I’m using it to refer to the collection of principles that eventually came to be known as the Copenhagen Interpretation even when referring to events that occurred before the actual term was invented.

As Becker illustrates in his book, it would be hard to overstate the influence Bohr had over the development of quantum theory as it was developing from its early embryonic stages. In 1913 Bohr used Planck’s quantum theory and Ernest Rutherford’s model of the atom as a springboard to create what is now known as the Bohr model of the atom. This is the model for the atom which we commonly use even today to visualize an atom — a nucleus surrounded by concentric orbital shells which contain electrons, and which electrons can jump between (the “quantum jump”). The model was groundbreaking, and was one of the major contributions that led to Bohr receiving the Nobel Prize in 1922.

By 1925, as a Nobel Laureate and one of the leading lights in the still-nascent field of quantum theory, Bohr headed up the Institute for Theoretical Physics at the University of Copenhagen. That year, one of his students, Werner Heisenberg, published the paper that ultimately led to Heisenberg promulgating the revolutionary matrix mechanics formulation of quantum mechanics. Two years later, while working under Bohr, Heisenberg developed his Uncertainty Principle*. Paul Dirac and Ernest Schrodinger spent time at the Institute during this time as well, and the Institute quickly became Ground Zero for the development of quantum theory and quantum mechanics.

* The Uncertainty Principle provides that there is an inherent mathematical limit to how much we can know about both the position and the momentum of a particle — the more certainty we have about one, the less we have about the other. This is often interpreted as meaning that the act of measuring position or momentum changes the state of the particle (the Observer Effect) — and that does happen, since the interaction of a photon to measure results in a change in the particle’s position and/or momentum, and was the original basis of Heisenberg’s theory. However, the Uncertainty Principle exists independent of any external measurement — for example, atoms cooled to extremely low temperatures have very little uncertainty in momentum, resulting in their “smearing,” their wavefunctions overlapping with other nearby atoms, and their occupying the same states, resulting in a Bose-Einstein Condensate.

As work developed in these fields, Becker appears to acknowledge, Bohr was less theoretical physicist and more of a guiding supervisor and philosopher. This is complicated by the fact that Bohr was one of those scientists who, as Becker notes repeatedly, struggled mightily to put his thoughts into words, resulting in his writing being famously opaque, his views vague and sometimes contradictory. The combination of Bohr being revered by the generation of quantum physicists working in the pre-WWII era — as almost a gatekeeper, someone whose blessing was needed for one’s work to have merit — and his being unable to express his views clearly resulted in Bohr seemingly transferring into an oracle over time.

Whatever weaknesses Bohr had in elucidating his own fundamental opinions, he was a successful advocate of the theories he and his students advanced. Albert Einstein, long painted in the second half of his career as a curmudgeon who wrongheadedly refused to accept quantum mechanics, challenged the inherently probabilistic nature of the universe described by the Copenhagen Interpretation (“god doesn’t play dice”)*, and challenged the Copenhagen Interpretation over the next decade, particularly its violation of causality and its reliance on the observer effect in wave function collapse.

* The actual quote, translated into English, is ‘I, at any rate, am convinced that [God] does not throw dice,’ from a letter written by Einstein to Max Born in 1926, and is an unfair oversimplification of the subtle and complicated views Einstein held on the subject of quantum mechanics.

Einstein argued that, at a minimum, the Copenhagen Interpretation was incomplete, and argued for the existence of “hidden variables” or other phenomena that were driving the results the Copenhagen Interpretation was finding. Einstein’s problem, however, was that, whatever the reason for it, the math behind the Copenhagen Interpretation worked, and Einstein couldn’t give a definitive contrary explanation as to why. When John von Neumann produced a proof that (supposedly)* conclusively established that there could be no hidden variables, that appeared to put an end to the debate. Bohr won, Einstein lost, and the Copenhagen Interpretation was the Law of the Land.

* As it turns out, that proof was flawed, and a central theme of the second half of the book is an individual challenging the von Neumann proof, having found the flaw, and being ignored because, well, he’s John von Neumann and you’re just some rando. It took decades, but the flawed nature of the proof appears to have now been accepted.

Becker’s deep dive into the historical underpinnings of both the Copenhagen Interpretation — which is, in essence, an umbrella term for various underlying views and principles which are generally embraced by those who studied under Bohr or his students, and who built upon the work derived therefrom — and its almost universal adoption in the twentieth century lays the groundwork for the second half of the book, in which he follows the efforts of a few isolated individuals who sought to challenge what had become quantum mechanical orthodoxy.

Becker emphasizes what can best be described as a philosophical split between what can best be described as “mainstream” Copenhagen Interpretation and those who question it. That philosophical split is over the importance — relevance, even — of understanding “why” quantum mechanics works. While Bohr himself was not necessarily completely dismissive of the “why,” he never really elucidated a comprehensive and coherent explanation as to the “why”s, and over time, adherents of the Copenhagen Interpretation mostly, according to Becker, quit worrying or caring about the whys of it. Instead, the mindset that Becker lays out is one of “Shut up and calculate!” (a phrase coined by N. David Merman, though often attributed to Richard Feynman) — the math works, the theories accurately predict the results, and that’s all that matters.

The most significant example of this problem is the collapse of the wave function, which is exemplified in the Two-Slit Problem*, a thought experiment that has since been experimentally verified which showed (among other things) that, under the rules of quantum mechanics, whether a single photon of light acts as a wave or a particle depends on whether it is being observed.

* I remember the first time I read about this, in a book called “Schrodinger’s Kittens and the Search for Reality,” by John Gribbin. It blew my mind. I had to re-read it a couple of times to make sure I understood it. Niels Bohr famously said, “A person who wasn’t outraged on first hearing about quantum theory didn’t understand what had been said,” and that describes my reaction in reading Gribbin’s book for the first time.

While much of quantum physics is inherently unintuitive, the idea that a particle behaves differently depending on whether or not it is observed goes well beyond unintuitive, and even beyond anthropocentrism into the realm of solipsism. Bohr espoused the theory of complementarity — the idea that objects have complementary properties that cannot be measured simultaneously — as a way of getting around the subjective element of the “observer effect.”

This line of thought seems to hold that what an object does when it is not being measured is unknowable, and thus irrelevant. This leads to the philosophical split mentioned above, whereby the Copenhagen Interpretation gets characterized as not describing reality, but simply providing a mathematical framework that is describing what is happening at the quantum level. Under this mindset, whether or not a photon is in reality a wave, a particle, sometimes one and sometimes the other, both, or something else entirely is irrelevant — since the math works, there’s no reason to wonder whether or not it reflects a literal depiction of what is happening at that level.

Becker opines that disregarding “what is real” over the second half of the twentieth century, and the embrace of the Copenhagen Interpretation without regard to what the results and data say about the underlying nature of reality, is due in no small part to the Cold War and the extent to which university funding was tied to government grants and the ability to produce practical results. Becker spends a fair amount of time looking at the politics of the Western World — particularly the United States — in the post-war era, and how it impacted not just fields of study, but individuals. Becker writes at length about the travails of David Bohm, and iconoclastic physicist who challenged the Copenhagen Interpretation, but who also was hamstrung in his ability to teach or work in the United States do to his being a Communist. Bohm’s quixotic life and career, and alternative interpretations, get quite a bit of coverage in “What Is Real?”

Becker tracks the efforts of the occasional renegade, leading to John Stewart Bell, who both identified the flaw in von Neumann’s proof and established that the local hidden variable theory set forth in the Einstein-Podolsky-Rosen Paradox (part of the challenge to the Copenhagen Interpretation, and put out in 1935) violated quantum theory. The EPR Paradox noted that under the quantum mechanics, there would exist the phenomenon of “quantum entanglement” — particles that are “entangled” in such a way that, when separated, measuring the spin state of one of them would immediately result in the other particle having the opposite spin state. This phenomenon — derided by Einstein as “spooky action at a distance” — violated locality (and thus a fundamental part of causality). Einstein hypothesized that local hidden variables would have to be involved, thus preserving the notion of locality and establishing that the Copenhagen Interpretation was incomplete.

Bell ends up being the hero of “What is Real?”, as Becker follows out Bell’s Theorem has led to the questioning of the Copenhagen Interpretation orthodoxy and the promulgation of alternative theories — notably the “many worlds” theory, which Becker describes as having gained significant support. Under the “many worlds” theory, rather than a collapse of the wave function triggered by an observation resulting in a particle or object assuming one of the possible forms it could take, with a likelihood based on the probabilistic nature of the wave function, every possible outcome available under the probabilistic model occurs, with each outcome results in the branching off of a new universe.

While Becker says he himself doesn’t “advocate for the many-worlds interpretation” in “What is Real?”, its hard to come away from Becker’s book not feeling like that is his view. And there’s appeal to the many worlds interpretation — not least of which that, it seems to me at least, it provides some actual explanation for what is occurring on the quantum level. Conversely, the Copenhagen Interpretation, as set forth by Becker, requires one to either assume everything is probabilistic and nothing is real until the act of observing — rife with philosophical questions — or choosing to just “shut up and calculate!”, and if one does choose to think about the “whys,” having to accept the equivalent of Xena’s “a wizard did it” explanation.

One of the problems that one has in grappling with this issue — particularly in the framework of the Copenhagen Interpretation/Not Copenhagen Interpretation duality Becker uses in his book — is that, as Becker acknowledges, there is not one specific Copenhagen Interpretation. It is not a specific set of laws and rules so much as it is a collection of guiding principles which have been used by mainstream physicists for most of the last century or so. Becker notes that such a loosy-goosy definition provides a degree of flexibility to its adherents, as two followers of the Copenhagen Interpretation may have diametrically opposed views as to a certain element of quantum theory, and yet still rightfully claim to be part of the Copenhagen Interpretation orthodoxy. That can make critiquing the Copenhagen Interpretation like nailing Jello to the wall, as a particular criticism can be deflected by saying, well, that doesn’t mean the Copenhagen Interpretation is wrong, because here’s someone who is an adherent who agrees with that criticism, and really, its a theory that is bigger than just that one particular issue. Conversely, though, that big umbrella means that there are many more things that Becker can identify as being part of the Copenhagen Interpretation and attack, thereby eroding the credibility of the theory as a whole.

That being said, it seems like there’s something apropos about the Copenhagen Interpretation, which has as one of its core tenets the fundamental indeterminability of things at the quantum level, having such a level of uncertainty as to what it really is.

Personally, I understand the desire to look at the underpinnings of what quantum mechanics describes. On a practical level, I get that it is enough to know that the math works, and not worry about the extent to which the math is simply a formalism, a symbolic approximation of things we don’t — maybe can’t — understand at the quantum level, versus an accurate description of reality. I don’t have to know how an internal combustion engine works in order to drive a car.

But that doesn’t mean that I don’t want to know — that I don’t want to understanding that fundamental question that is the title of Becker’s book. And its part of what made it such a compelling read for me, and a book that I’m likely going to re-read at some point in the future.