4.5 stars, rounding up. Adam Forrest Kay is really speaking to me here, as someone who has always found quantum physics to be deeply unsatisfying (and confusing). His point is, essentially, that in every case in science where a statistical model was developed to describe something, the statistics were reflecting a deeper physical mechanism that we only later were able to discover and understand -- yet, when that dynamic plays out with quantum physics, the quantum physicists insist that there is no deeper system, no "hidden variables," and that reality simply <i>is</i> probabilistic. But why, Kay argues, should that possibly be true <i>only</i> in the case of quantum physics?

Kay does a good job here explaining how the "Copenhagen interpretation" came to be the dominant scientific explanation of quantum physics, with a lot of historical parallels of other moments in scientific history where the dominant explanation of a thing was <i>wrong</i> (e.g. phlogiston, the caloric theory of heat, miasma theory). His message to quantum theorists is to be humble: plenty of scientific certainties have been overturned before. Kay does seem to have a bit of a chip on his shoulder about this, as one of the minority of scientists who are working to try to determine those "hidden variables" that the Copenhagen interpretation dismisses. Along the way he spends a good bit of time describing some quite exciting developments in what are called "hydrodyamic quantum analogues" where wave/particle behavior can be exhibited through purely classical, fluid-dynamical means, and while I confess I don't totally understand what he's going on about there I do love to hear that people are doing research that might "classicize" quantum physics.

A love letter to the physics community ... but likely to cause a stir in some circles.

Kay does his best to bring the gentle reader into the realm of physics and especially quantum mechanics. I admit, even as a PhD holder in the sciences, I was lost at several points. There's just so much one can do, I suppose. But I urge the reader to carry on. Concepts and what they're all about are repeated and re-introduced. There are many colourful metaphors and examples, and several interludes that may seem utterly disconnected from the main thread, but end up masterful and compelling analogues.

For me, the real treat was less about the physics and more about the love letter. I'll write it again: this is a love letter! The penmanship, which had me in equal parts riveted and in stitches)! The tale, which navigates a long tapestry of personal and professional histories ... perhaps the most engaging parts were about the relationships among these people ... from rivalry to camaraderie and everything in between ... somehow Kay has unearthed the diaries (or near enough) of some of the greatest actors on the physics stage and bared it all for us. All meticulously referenced.

I had no idea that Bohr was such a godlike figure, nor that Einstein was such a joker ... nor that the physics community has been and continues to be divided on "the facts," which some believe are decided and others, not so much. Kay has his own opinion. "Positive is rat poison" he writes at one point. The main point, rather than anything about physics and quantum theory, is that people like boxes. And when people make a box, they want to keep it ... at all costs. And this is anti-scientific. Yet, as Kay writes, "real science is done by real animals, it is an animal institution, and as such is subject to many unscientific forces." Yup, we're power-hungry oligarchs with no shortage of bias! Kay deftly highlights some of the most notable of such blips in quantum physics. I had no idea the history of fundamentals was so exciting ... but why not, when we're all beasts blundering our way through the natural world together?

On that note, the history of physics is very white and very male, but Kay does his best to incorporate women, speakers of other tongues, and non-Westerners. Still, there's a lot of language that reinforces the historical and contemporary wiener fest that is physics. For instance, Kay updates one hypothetical to be in a lab rather than a cafe, but it carries the same tropes and might even be worse off, since now we're bringing cisheterosexuality into the workplace. And, as per usual, things like atoms are anthropomorphized as "little guys."

I was also a but miffed that Kay in one sentence denounces non-scientists who "like to appropriate scientific thought" after giving an example and going on to provide even more of scientists, especially physicists, indulging in pseudo-scientific malarkey. Call all the spades a spade!

Nevertheless, this is a gripping narrative and nice introduction to quantum physics: the people, the problems, and the pandemonium. We still have much to learn, about the natural world and about ourselves.

Such a perfect read for a science geek like me who loves finding out more about what is out there, about what more possible science advancements are even possible, and who just loves, loves, loves, and enjoys reading things that make me… feel smarter.

This is an excellent, in-depth look from an experimental physicist on why the Copenhagen interpretation of quantum physics can't be the end-all, be-all on the subject. The book is overly long and, in places, pleading, but the author justifies what we all know deep down - the theoretical physicists aren't done with their work. Nonsensical results like multiple branching worlds can't be the answer - they can only point to our incomplete understanding. The author uses his work in Hyrdoquantum Dynanmics to draw parallels between the behavior of oil particles in those experiments and subatomic particles. The experiment do seem to point to something else going on, and while one could argue the drops aren't subatomixc particles, the author's real strong point is the reasoning why quantum physics must be incomplete (spoiler: statistical theories are histrorically incomplete). Einstein is vindicated, and theoretical phsyicists need to get to work.