## The Dying Art of Fact Checking

I mentioned last week that I had begun reading Jim Baggott’s The Quantum Story: A History in 40 Moments, inspired by Jeremy Bernstein’s WSJ review just short of a year ago. I’m on moment #25 now, having made it from Max Planck’s introduction of quantized energy in Berlin in 1900 to Sheldon Glashow’s introduction of the charm quark at Harvard in February 1970.*

**Speaking of which, I was there! February 1970 would have been the start of spring semester of my freshman year. I was taking the honors freshman physics course. No one bothered to tell me that exciting developments were going on right around me. From where I sat, physics was pretty darn boring.
*

*The Quantum Story* has been interesting, but it’s a puzzle what Baggott assumes of his readers. He doesn’t explain much. I suppose you’re actually supposed to know the physics already. It helps, for instance, to know about the strong and weak forces, which appear on the scene quite suddenly, as the book shifts from the oft-repeated history of the early days of quantum theory through World War II to quantum electrodynamics, electro-weak theory, and high energy experimental physics. I was happily reading about the good old days of Franck, Einstein, Bohr, Heisenberg, and Schrödinger, then the war comes and suddenly they have left the stage, supplanted by Feynman and Dyson, Weinberg and Glashow. The material on the Bohr-Einstein debates about quantum mechanics are well told. Einstein comes off as a huge pest, a meddling nay-sayer whose best days are behind him, mucking up the works by making everyone stop to listen to his latest criticisms. Also well told is the story of Heisenberg’s ambiguous allegiance to Nazi Germany and its atomic bomb effort, which he was either actively leading or discouraging. After the war, the book seems to lose its narrative thread.

But I’m here to tell a different story, the sad story of the dying art of fact checking. Moment 20 takes place in Princeton in 1954. It’s a technical tale, about the strong force, quantum field theory, and the work of Chen Ning Yang. To get there, Baggott, backs up to talk about earlier work of Hermann Weyl, one of the giants of twentieth-century mathematics and a hero of mine. Like any mathematician who has done any work in the field known as representation theory of Lie groups, I am greatly in Weyl’s debt. Lie groups are the very objects that became crucial to further developments in quantum physics. Baggott explains that

Weyl had worked on the representation theory of types of symmetry groups called Lie groups, named for the eighteenth century Norwegian mathematician Sophus Lie.

Sigh. This is mostly true. The problem is, Sophus Lie didn’t live in the eighteenth century. He was born near the end of 1842 and died in early 1899. And anyone with the slightest knowledge of the history of mathematics would know that the objects named after Lie couldn’t possibly have come into existence in the eighteenth century, unless some mathematician headed back in a time machine.

It’s discouraging. In Bernstein’s rave review of the book, he writes that Baggott “manages to get the people right. I know this because for many of the scenes he describes I was there.” I suspect Bernstein doesn’t have Lie’s time in mind.

Baggott continues, in the very next sentence, with what I consider another clunker.

These are groups of

continuoussymmetry transformations, involving gradual change of one or more parameters rather than an instantaneous flipping from one form to another, as in a mirror reflection.

I realize this post isn’t the place to get technical, but Baggott’s sentence seems to confuse the continuous change of parameters defining elements of the group with the actions the group elements perform on space. Baggott follows with a description of the group U(1), which plays a role in the physics to follow, describing it (correctly) as the collection of rotations of the plane (or, say, a piece of paper) through all possible angles. This is “continuous” in the sense that one can move from one rotation angle to another smoothly through all angles. In contrast, the group consisting of just the 0 degree and 180 degree rotations would not be continuous, since one can’t go smoothly from doing nothing to doing the 180 degree rotation. I suppose Baggott understands that. But it’s not at all what he says. Even in a continuous or Lie group, the individual rotations do perform what he describes as “instantaneous flipping” from one form to another.

Maybe I’m just mis-reading him in his effort to explain mathematical concepts in ordinary language. It’s difficult to do. Then again, I have no idea why he even bothers trying, given all the other language he throws around at this point in the book with no explanation at all.

I’ll keep reading. I’m eager to learn more. But I’m also eager to get on to the next book.