A Guess at the Riddle: Essays on the Physical Underpinnings of Quantum Mechanics

by David Z Albert

From the celebrated author of Quantum Mechanics and Experience comes an original and exhilarating attempt at making sense of the strange laws of quantum mechanics.

A century ago, a brilliant circle of physicists around Niels Bohr argued that the search for an objective, realistic, and mechanical picture of the inner workings of the atom—the kind of picture that had previously been an ideal of classical physics—was doomed to fail. Today, there is widespread agreement among philosophers and physicists that those arguments were wrong. However, the question of what that picture might look like, and how it might fit into a comprehensive picture of physical reality, remains unsettled.

In A Guess at the Riddle, philosopher David Z Albert argues that the distinctively strange features of quantum mechanics begin to make sense once we conceive of the wave function, vibrating and evolving in high-dimensional space, as the concrete, fundamental physical “stuff” of the universe. Starting with simple mechanical models, Albert methodically constructs the defining features of quantum mechanics from scratch. He shows how the entire history of our familiar, three-dimensional universe can be discerned in the wave function’s intricate pattern of ripples and whorls. A major new work in the foundations of physics, A Guess at the Riddle is poised to transform our understanding of the basic architecture of the universe.

Genres: Nonfiction

135 pages, Kindle Edition

Published September 19, 2023

Reviews

[Orin Harris · Rating 5 out of 5]

I gave this 5 stars because it is a thought-provoking work, despite some issues described below.

First, two notes to potential readers are in order. First note: you probably won’t appreciate or fully make sense of this book if you do not have an academic background in physics or philosophy of physics. Second note: if you are not familiar with David Albert, he has a unique, precise, deliberate way of speaking that comes across in this book as though through dictation. The reader may want to look up some youtube videos of David speaking in order to better appreciate his writing style.

Here are a few noted defects of this work (one for each of the three chapters):

1. In Chapter 1 David painstakingly shepards us through an argument that a careful analysis of classical mechanics should lead one to consider, even without empirical signposts whatsoever, quantum mechanics as an inevitable possibility. The key insight is that the consideration of multiple particles interacting in phase space (as opposed to the ordinary situation in Hamiltonian mechanics of a many-particle system being represented as a single high-dimensional point in phase space) naturally leads to entanglement between “branches” of states which, upon measurement, get “pushed off into another dimension.” The denouement of David’s analysis is the representation a physical state of affairs that is identical to the many-worlds interpretation of quantum mechanics; as David writes, “Quantum-mechanical sorts of behavior seem to require that the space of the elementary physical determinables is bigger than the space of ordinary material things,” and indeed gives an explicit example of branches of the wave function being “pushed off” into that space in exactly the same way that they are under many-worlds. And so it was baffling to me that David then dismisses the very ontology he has himself so painstakingly birthed, with a mere sentence fragment and a footnote which cryptically states that the interpretation is “incoherent” because of the difficulty of explaining probabilities.

Now, the position that David is flippantly gesturing at here is well-known to those who study quantum interpretations, but it is particularly strange in this context — for one because he has himself rediscovered and presented something identical to many-worlds, for two because this work is focused on the study of quantum interpretations and many-worlds is one of the most studied in the quantum interpretations literature, and for three because David is elsewhere so very careful and exhaustive and humble in his analysis — that he sets aside nothing more than a single sentence to dismiss even the discussion of the topic. It is made further bizarre by his particular choice of words, not taking issue with any derivation of the Born rule, but with probabilities existing at all in such a deterministic interpretation. The reason I find this such an odd stance is that it is famously easy to come up with a thought experiment, even classically (the “Kirk transporter malfunction” or similar explored by Parfit, Dennet, etc) where one is forced to accept chance in answering a question like “which planet am I going to be on when I open my eyes after transport duplication.” Regardless of where one stands on what those probabilities turn out to be, the fact that subjective probabilities should exist at all in such duplicative frameworks is definitively proven by such thought experiments.

2. In Chapter 2 David dismisses the objection that “the kinds of explanations that this embedding theory has to offer us are extrinsic explanations rather than intrinsic ones” because, he claims, such a criticism can equally be leveled at any physical theory formulated in terms of any abstract objects at all. I don’t find this convincing, and like my previous criticism, many more words are warranted here. Here is an explicit counterexample to David’s claim: mathematical platonism as a physical ontology.

3. In Chapter 3 David makes a big deal of the Hamilton-Jacobi transformation, claiming that “the mere mathematical existence of such a mapping is apparently going to commit the global functionalist to the claim that [all the complexity of the physical universe can be reduced to] a single structureless point-like physical item at rest in a sufficiently high-dimensional fundamental space, and to stipulate that the single law of the evolution of the world is that nothing ever happens.” But, as I think David does (or should) know, this is incredibly misleading. David himself explains that the mapping itself is of course complicated and time-dependent, and that it encodes the dynamics, not the law of evolution of the single point described above. Maybe I misunderstood David here, that he meant this kind of wording as a foil for his later arguments, but he made quite a bit hay of this point, so I don’t think so.

[Emin Orhan · Rating 2 out of 5]

Incredibly tedious. Be warned that this is the opposite of a popular book. It's an extremely niche book that is maybe of interest to three other philosophers of physics, dealing with insignificant minutiae and made-up problems mostly on the philosophy side (particularly essays 2 and 3; and they have very little to do with quantum mechanics per se).