I recently read, and very much enjoyed, Quantum Reality (2020) by Jim Baggot, an author (and speaker) I’ve come to like a lot. I respect his grounded approach to physics, and we share that we’re both committed to metaphysical realism. Almost two years ago, I posted about his 2014 book Farewell to Reality: How Modern Physics Has Betrayed the Search for Scientific Truth, which I also very much enjoyed.
This book is one of a whole handful of related books I bought recently now that I’m biting one more bullet and buying Kindle books from Amazon (the price being a huge draw; science books tend to be pricy in physical form).
The thread that runs through them is that each author is committed to realism, and each is disturbed about where modern physics has gone. Me, too!
I have been increasingly disturbed about modern physics ever since I read The Trouble with Physics (2006), by Lee Smolin. Even then, from years of following the well-grounded blogs of Sabine Hossenfelder and Peter Woit, I felt too many physicists had wandered from doing science to doing science fiction. I’m appalled by the notion of “post-empirical science” — a notion that couldn’t be more contrary to the spirit of science.
[See: Fairy Tale Physics (Apr 2020), Our BS Culture (Dec 2020), and Our Fertile Imagination (Jan 2021), for three of my more recent posts discussing the embrace of pure speculation by theorists and culture. It’s a trend that damages and undermines science in a time when science is under fire from politics and society. Proponents of Intelligent Design rightfully ask, “If multiverses that must be taken on faith are ‘science’ then why isn’t ID?” The truth is that both are fantasy bullshit (FBS).]
Speaking of Peter Woit and Lee Smolin, among that aforementioned handful of new books is Woit’s Not Even Wrong (2006), which I’ve been meaning to read for years, and Smolin’s latest book, Einstein’s Unfinished Revolution: The Search for What Lies Beyond the Quantum (2019). I read the former before reading Quantum Reality and am currently enjoying the latter.
Also in the handful is Fashion, Faith, and Fantasy in the New Physics of the Universe (2016), the most recent popular science book from Roger Penrose. It’s a book I’ve been wanting to read since I first heard of it.
Penrose’s books aren’t for the faint of heart. In the 1990s, it took me years and multiple readings to fully absorb his 1989 book, The Emperor’s New Mind: Concerning Computers, Minds and The Laws of Physics. (In large part I owe my skepticism about computationalism to that book. It planted the first seed of discontent about a topic I’d taken for granted until then.) Recently I posted (in fact, twice) about his 2010 book, Cycles of Time: An Extraordinary New View of the Universe, which explores his Conformal Cyclic Cosmology (CCC) hypothesis. (While I enjoyed Cycles of Time, the CCC hypothesis is pure speculation, which Penrose readily admits. See Sabine Hossenfelder’s recent video about it.)
You might be thinking, “Wait, that’s four books. A handful should be five!” I also bought Baggott’s The Quantum Cookbook: Mathematical Recipes for the Foundations of Quantum Mechanics (2020). As the title suggests, it’s for those with mathematical inclinations. It straddles the gap between textbook and popular science book. Each chapter shows how a famous physicist derived a famous physics equation. For examples, the first chapter takes the reader through how Planck derived E=hv, the second how Einstein derived E=mc2 (which is as far as I’ve gotten so far).
In Not Even Wrong, Woit explores why string theory is an interesting idea that’s become fairy tale physics. As he mentions, many physicists see it as pure math because it offers no evidence or way of testing the theory (and has the landscape problem). On the other hand, mathematicians see it as physics because, as math, it lacks the rigor that’s foundational in math. It seems many assume that, if not to them, it somehow makes sense to someone. (Woit, by the way, is primarily a mathematician with a strong interest in physics.)
Two books by Brian Greene, The Elegant Universe: Superstrings, Hidden Dimensions, and the Quest for the Ultimate Theory (1999) and The Fabric of the Cosmos: Space, Time, and the Texture of Reality (2004), got me excited about string theory, but everything I read since then gave me a different outlook (starting with Smolin’s The Trouble with Physics).
In Fashion, Faith, and Fantasy, Penrose echoes that in his first section, Fashion, which is about how string theory became such a strong fashion in physics that many new physicists saw no alternative but to work on it if they wanted a job or any funding. As I already quite agree, I jumped to section two, Faith, which is about the abiding faith many theorists have that quantum mechanics is a complete description of reality.
As I mentioned, Penrose’s books aren’t for the faint of heart. He is far more willing to dive into the technical weeds than most popular science writers. While reading section two, I decided to rest my mind and read Not Even Wrong, Quantum Reality, and currently, Einstein’s Unfinished Revolution.
I’ll get back to Fashion, Faith, and Fantasy in due time. Since he refers to it many times in the book, I also bought his 2004 book, The Road to Reality: A Complete Guide to the Laws of the Universe, so I have plenty of Penrose waiting to challenge my mind. I am looking forward to what his Fantasy section is about!
Which finally brings me back to Baggott, Quantum Reality, and metaphysical realism.
The heart of the issue is the wavefunction. Is it something real or does it merely encode what we know about a quantum system? And if it is real, exactly what is it?
An issue like this doesn’t exist in classical physics where, at least to a first approximation, the equations “wear” their reality in plain sight and there is no confusion. A good example is Newton’s Second Law, usually expressed as F=ma (force is equal to mass time acceleration).
Above I said, “to a first approximation” because a deeper look turns up a puzzle: what is mass? Newton defined it as volume times density but defines density as mass per volume — which is circular and, thus, not much of a definition. Baggott wrote a whole book about it, Mass: The Quest to Understand Matter from Greek Atoms to Quantum Fields (2017).
Quantum Reality features both Preamble and a Prologue, the latter subtitled Why Didn’t Somebody Tell Me About All This Before? In the Prologue, Baggott touches on his own journey, first learning basic quantum mechanics as part of learning chemistry but then encountering the famous EPR paper from 1935 as well as the experiments by Alain Aspect in 1982. He reports that it sent him into a tailspin and began a 30-year journey to try to understand.
He ends the Prologue by saying: “I can happily attest to the fact that, like charismatic physicist Richard Feynman, I still don’t understand quantum mechanics. But I think I now understand why.”
Part I of Quantum Reality is called The Rules of the Game, and it’s an overview of our understanding of quantum mechanics. Here are the chapter headings:
- The Complete Guide to Quantum Mechanics (abridged); Everything You’ve Ever Wanted to Know, and a Few Things You Didn’t
- Just What is This Thing Called ‘Reality’, Anyway; The Philosopher and the Scientist: Metaphysical Preconceptions and Empirical Data
- Sailing on the Sea of Representation; How Scientific Theories Work (and Sometimes Don’t)
- When Einstein Came Down to Breakfast; Because You Can’t Write a Book About Quantum Mechanics without a Chapter on the Bohr-Einstein Debate
It’s in this part that he introduces his key metaphor of the Ship of Science sailing the Sea of Representation back and forth between the shores of Empirical Reality and Metaphysical Reality.
During its back-and-forth journeys it needs to avoid the rocky shoal of Scylla, which lies close to the shores of Empirical Reality. He defines it as “rather empty instrumentalism,” that, while perfectly valid empirically, is devoid of “any real physical insight and understanding.”
The Ship of Science also needs to avoid the whirlpool of Charybdis, which lies close the beaches of Metaphysical Reality. “It is a whirlpool of wild, unconstrained metaphysical nonsense.”
He has developed this metaphor over time, and I can recall him mentioning it in talks that predate this book. (I do not recall it being mentioned in Farewell to Reality, but my memory can be like Swiss cheese when it comes to some things. Like Sherlock Holmes, I don’t even try to remember things that I don’t deem useful.)
The key point of the metaphor is that science proceeds by moving back and forth between metaphysical speculation and experiment, and that both are crucial to the process. No scientific theory is without some metaphysical assumptions, but those must be grounded in experiment if they are to mean anything.
In Part II, Playing the Game, Baggott covers many of the popular interpretations of quantum mechanics (the only physics in which interpretation is even necessary). Here are the chapter headings:
- Quantum Mechanics is Complete So Just Shut Up and Calculate; The View from Scylla: The Legacy of Copenhagen, Relational Quantum Mechanics, and the Role of Information.
- Quantum Mechanics is Complete But We Need to Reinterpret What it Says; Revisiting Quantum Probability: Reasonable Axioms, Consistent Histories, and QBism.
- Quantum Mechanics is Complete So We Need to Add Some Things; Statistical Interpretations Based on Local and Crypto Non-local Hidden Variables.
- Quantum Mechanics is Incomplete So We Need to Add Some Other Things; Pilot Waves, Quantum Potentials, and Physical Collapse Mechanisms.
- Quantum Mechanics is Incomplete Because We Need to Include My Mind (or should that be Your Mind?); Von Neumann’s Ego, Wigner’s Friend, the Participatory Universe, and the Quantum Ghost in the Machine.
- Quantum Mechanics is Incomplete Because… Okay, I Give Up; The View from Charybdis: Everett, Many Worlds, and the Multiverse
The basic tension here is between the decidedly anti-realist views of Bohr and, hence, the Copenhagen school (which dominated quantum physics) and those, such as Einstein, who preferred a realist approach.
The problem is that, if we take QM as complete, then we’re stuck with either anti-realism or some metaphysical extremes (such as the MWI, which Baggott paints as “magical realism” — a point I’ve made repeatedly).
Baggott discusses how quantum physics seems to have encountered Kant’s noumena, the things-in-themselves that we can only know through their representations in our senses. Anti-realist views accept that we can never know them, only those appearances through their interactions with our experiments. Of course, all our experiments use classical physics. The quantum world, in some sense, is indeed inaccessible to us. We can never actually see a superposition, for instance.
This has gotten long, so I’ll stop, but I expect I’ll return to this and the other books in future posts. I have strong objections to the fantasy bullshit the science and social world seems to wallow in these days, and while posts may do nothing, expressing my dissatisfaction, I’ve always found, is good for my mental health.
If, like me, you share a sense of disquiet about perceived fantasy bullshit in science, if you are, to your core, a metaphysical realist, then I highly recommend Quantum Reality as a great read. The other books I’ve mentioned here also express the need for grounding in empiricism and realism.
For whatever it’s worth, being a metaphysical realist puts one in the company of Albert Einstein, who spent his life trying (unsuccessfully) to complete quantum mechanics.
And the thing is, it seems almost self-evident that QM is incomplete because it is at odds with our other greatest theory, general relativity (which is an entirely realist theory). It seems to me almost foolish to accept QM as is given that conflict.
As a final note, I’ve never been much taken with Carlo Rovelli, who’ve I’ve seen as not just an anti-realist, but as something of a space cadet (as we used to say). I’ve also never been taken with theories that make relations fundamental (I see them as necessarily secondary). I’ve long thought Leibniz and relationalism is “not even wrong.”
So, I never bothered with Rovelli’s Relational QM, but after reading Baggott’s book I see that Rovelli, at least in RQM, is a realist in seeing quantum objects as real. The theory, however, is still anti-realist in seeing that the only access to those objects is through their relations with our (classical) experiments. In that sense, he is aligned with Bohr.
Stay realist, my friends! Go forth and spread beauty and light.