Book review: Quantum mechanics and quantum mechanics. David Kaiser's "Quantum Legacies: Dispatches from an Uncertain World"

David Kaiser is a remarkable man. He has two PhDs from Harvard, one in physics and one in the history of science, and is a professor in the Science, Technology and Society department at MIT. He has written excellent books on the history of particle physics and the quirky personalities inhabiting this world. On top of it all he is a genuinely nice guy - he once wrote me a long email out of the blue, complimenting me on a review of his book "How the Hippies Saved Physics". And while his primary focus is the history and philosophy of physics, Kaiser still seems to find time for doing research in quantum entanglement.

What makes Kaiser unique is the attention he gives to what we can call the sociological aspects of physics, things like the physics job market, portrayals of physicists in the humanities, parallel threads of science and history, and perhaps most uniquely, the publications of physics - both the bread-and-butter textbooks that students use and the popular physics books written for laymen. It's this careful analysis of physics's sociological aspects that makes "Quantum Legacies" a delightful read, tread as it does on some of the under-explored aspects of physics. There are chapters on quantum indeterminacy and entanglement and the lives of Schrödinger, Einstein and Dirac, a nice chapter on computing and von Neumann's computer and interesting essays on the Large Hadron Collider and the tragic Superconducting Supercollider which was shelved in 1993 and the Higgs boson. All these are worth reading. But the real gem in the book as far as I am concerned is a collection of three chapters on physics publishing; this is the kind of material that you won't find in other books on the history and philosophy of physics.

The first chapter is about a book that fascinated me to no end while I was growing up - Fritjof Capra's "The Tao of Physics" which explored parallels between quantum physics and Eastern mysticism. This book along with the downright dubious "aliens-visited-earth" literature by the Danish writer Erich von Daniken dotted my bedroom for a while until I grew up and discovered in particular that Daniken was peddling nonsense. But Capra isn't that easy to dismiss, especially as Kaiser tells us, his book hit the market at a perfect time in 1975 when physicists had become disillusioned by the Vietnam War, the public had become disillusioned by physicists, and both groups of people had become smitten with the countercultural movement, Woodstock and Ravi Shankar. There could be no better time for a book exploring the ins and outs of both the bizarre world of quantum mechanics and the mystical world of Buddhism and the "Dance of Shiva" to become popular. Kaiser describes how Capra's book set the tone for many similar ones, and while most of the parallels described in it are fanciful, it did get the public interested in both quantum physics and Eastern philosophy - no small feat. Capra's own personal story, one in which he comes to the United States from Vienna, has a hard time making ends meet and goes back and then decides to first write a textbook and then a more unique popular book based on his experiences in California and advice from famed physicist Victor Weisskopf, is also quite interesting.

The second interesting chapter is about a textbook, albeit a highly idiosyncratic one, that is a household name to students of general relativity - a 1200 page doorstop of a tome by Kip Thorne, Charles Misner and John Wheeler, all legendary physicists. "MTW" as the textbook became known was a kind of landmark event in physics publishing. The textbook was the first major book to introduce advanced undergraduate and graduate students to fascinating concepts like time dilation, spacetime curvature and black holes. The joke about its size was that not only was the book *about* gravity but that it also *generated* gravity. But everything about the book was highly unconventional and quirky, including the typeface, the non-linear narrative and most importantly, serious and advanced mathematical calculations interspersed with boxes containing cartoons, physicist biographies and outrageous speculations about wormholes and time travel. Most people didn't know what to make of it, and perhaps the best review came from the Indian-American astrophysicist Subrahmanyan Chandrasekhar who said, "The book espouses almost a missionary zeal in preaching its message. I (probably for historical reasons) am allergic to missionaries." Nonetheless, "MTW" occupies a pride of place in the history of physics textbooks, and a comparable one on sagging student shelves where it's probably more seen than read.

The last chapter and perhaps the one I found most interesting is about the content of traditional quantum mechanics textbook, which is really a history of the quantum mechanics textbook in general. The first quantum mechanics textbooks in the United States came out in the 1940s and 50s. Many of them came out of the first modern school of theoretical physics in the country founded by J. Robert Oppenheimer at the University of California, Berkeley. Two of Oppenheimer's students, David Bohm and Leonard Schiff, set the opposing tones for two different kinds of textbooks (I remember working through a bit of Schiff's book as an undergraduate). After the war Schiff taught at Stanford, Bohm at Princeton.

Bohm was old school and believed in teaching quantum mechanics as a subject fraught with fascinating paradoxes and philosophical speculations. His approach was very close in spirit to the raging debates of the original scientist-philosophers who had founded the revolutionary paradigm - Niels Bohr, Albert Einstein, Erwin Schrödinger and Werner Heisenberg in particular. Bohm of course had a very eventful life in which he was accused on being a Communist and hounded out of the country, after which he settled in England and became known for carrying out and publishing a set of philosophical dialogues with Indian philosopher J. D. Krishnamurthy. His textbook is still in print and is worth reading, but it's worth noting that the Schrödinger equation is not even introduced until several chapters into the volume.

Schiff's book was different and was a practical textbook that taught students how to solve problems, mirroring a philosophy called "shut up and calculate" that was then taking root in American higher physics education. The Schrödinger equation was introduced on page 6. What Kaiser fascinatingly demonstrates, often through analysis of the original lecture notes from Bohm and Schiff's classes, is that this attitude reflected both a mushrooming of physics students as well as a higher demand for physicists engendered by the Cold War and the military-industrial complex. Not surprisingly, when you had to turn out large numbers of competent physicists with jobs waiting for them in the nation's laboratories and universities, you had little time or patience to teach them the philosophical intricacies of the field. Shut up, calculate, and get out there and beat the Soviets became the mantra of the American physics establishment.

Fascinatingly, Kaiser finds out that the philosophical trends and the practical ones in physics textbook publishing wax and wane with the times; when the job market was good and enrollment was high, the practical school prevailed and textbooks accordingly reflected its preferences, and when the pickings were slim, the job market was tight and enrollment drastically dropped, philosophical questions started making a comeback on tests and in textbooks. Especially after 1970 when the job market tanked, the Vietnam War disillusioned many aspiring physicists and the countercultural movement took off, philosophical speculations took off as well and combined with Fritjof Capra's "The Tao of Physics". Perhaps the ultimate rejection of philosophy among physicists might be said to have come during the second job slump in the early 90s, when many physicists left the world of particles and fields for the world of parties and heels on Wall Street.

Physics publishing, the physics market, the lives of physicists and physics theories have a strange and unpredictable entanglement of their own, one which even Einstein and Bohr might not have anticipated. Kaiser's book explores these well and brings a unique perspective to some of the most interesting aspects of a science that has governed men's lives, their education and their wallets.