Quantum Field Theory, As Simply as Possible, Zee (2023)

The job of science is to render transparent, that which God left opaque. The job of teaching, and of writing — same thing, really — is to make it transparent to me. In Quantum Field Theory, As Simply as Possible [QFT ASAP], does the author succeed?

tl;dr Yes.

No, I don't fully — understand it — understand it; but then that was not the expectation.

In his own book QED: The Strange Theory of Light and Matter [QED STLM], Richard Feynman precludes this expectation when he explicitly declares that he will describe quantum electrodynamics, but that the reader will not understand it. Okay. He then goes on to call his theory "absurd", to say the ideas of quantum mechanics are "crazy" — its very nature "peculiar".

Venerable chemistry professor Harry Sisler professed before an auditorium of undergraduates in 1986, that it is a central fact of modern physics that so many find disturbing, that so much of it is just not reasonable (emphasis his). Formidable physics professor Alan Jacobs advised a graduate student in his office (me) in 1990, that when doing physics, one must translate any problem into pure mathematics and then — while doing the mathematics — pretend that the physical world just does not exist (emphasis mine).

In the concluding chapter of QFT ASAP, A. Zee takes this one step further, declaring:

The classical world is an illusion.

Gobsmacked. Clearly that domain of Reality outside our Goldilocks existence, where the Firmament is not Newtonian, it is Lovecraftian — the underpinnings of necromancy — and were a man to truly and fully understand and embrace it, he would surely run screaming into the night in search of a cyclopean wall within a non-Euclidean space behind which to hide.

But, I digress.

It seems likely that QED STLM served as inspiration for QFT ASAP (at least in part). Zee contributes a foreword to the current edition of Feynman's book, which (alas) Feynman could not reciprocate. I myself read one soon after the other. It does not diminish Feynman's status as a larger-than-life figure, but Zee wrote the better book. (Gasp)

Zee invokes (with a megaphone) Feynman's words about mathematics being the native language of Nature and the importance of learning that language. Many do. Not to disagree, but many also fail to appreciate that the reader's native language is not mathematics, and so fail to make use of the full power of human words. These authors' efforts to bring an understanding of advanced physics within reach of those who have not (yet) paid their mathematical dues, are noble — God's work — a thing to be encouraged. Zee observes and remarks on how Feynman sometimes struggles to be clear without the use of clarifying mathematics. But then, Zee himself sometimes goes on to suffer the same struggle. It's good work, yes. But it's hard work.

It is noteworthy that in a number of places, Zee gives descriptions that are exceptionally clear, insightful, and illuminating. Yes, he introduced me to ideas that were new to me, thus sharpening my mental image of the natural world. But also, there were some things I half-understood, knew of without really knowing, that his description brought into sharp focus. This is why we read non-fiction.

In his foreword to QED STLM, Zee describes how Feynman's description of QED, though incomplete, is in no way incorrect. And in his own book, he addresses himself enough times to the "nit-pickers" — among whom I imagine he himself is chief — that I am confident the mental image I have been given, though it is only a sketch, is faithful to the full painting that it outlines. It is a minor point, but the chronological cast of characters and symbol definitions given in the backmatter are very nicely constructed.

As for the writing style, it is lively, conversational, fully caffeinated, frenetic, digressive — bordering on Charlie at the Murder Board. The author is opinionated (sometimes even catty), willing to venture to the edge of his subject, or to leave the subject entirely. He talks about the limits of what is known, what is not known, what is suspected. All of this is good. This could have been a sterile, bloodless slog through a barren land but was instead more of a Mad Hatter's Tea Party. And, everyone likes a tea party.

I save the quibble for last. The author makes extensive use of footnotes and endnotes, including footnotes that point to endnotes, though I don't think any of the endnotes contained footnotes. There is great stuff in there and I know the author used it, in part, to quarantine equations. But, the page-flipping was too much. It disrupted the book's flow and detracted from the reading. In particular, the cross-references, both internal to the book and external to the author's other books, were distractions for me. I'm sure they were difficult to compile. But, the cross-references should go. Reading the next book from this author, I will probably skip over any notes and accept the loss. Quibble concluded.

I wonder which book that should be?