I recently acquired a copy of The Complete Idiot’s Guide to String Theory, by Scientific American’s George Musser, which has been out for a few months now. It’s a popular-level treatment of modern physics, string theory and quantum gravity, much like many other such books, but now in the “Complete Idiot’s” style of lots of cartoons, graphics, material set off in boxes, and short summaries of chapters. As such, I guess it does as good a job as any of putting this material in a form designed to sell it to as many people as possible.
Musser is an enthusiast for just about any and every speculative idea about space and time. Besides string theory, the book covers loop quantum gravity, causal dynamical triangulations, the idea that spacetime is a fluid or a giant computer, and even some ideas I’d never heard of (we live in 3 dimensions because “For the simplest particle, we can make three mutually exclusive measurements”????). The treatment is often breathless, continually going on about how “exciting” all this is. In many ways, the book reads like advertising copy, hyping the promise of ideas (with string theory getting the bulk of the attention) while mostly ignoring or minimizing their problems. For example, the chapter on symmetry contains more than two pages on the “Pros and Cons” of supersymmetry, but this turns out to be just about all “pros” until a short paragraph at the end that begins: “That said, supersymmetry raises some questions that physicists have yet to solve”.
I think I’m tempermentally allergic to this sort of discussion of science, but can see that some people like it and I realize there are arguments in its favor (get those kids and taxpayers excited about science!). Within the limits of such a genre, much of the book does a reasonable job, until the later chapters, where it starts to go off the rails.
There’s a chapter on “parallel universes” which promotes the anthropic multiverse, describing it as “the most promising scientifically” of all possible options. Despite the fact that many string theorists are extremely unhappy with seeing this kind of thing promoted as the received wisdom of their field, Musser claims that:
String theorists originally expected everything to be hard-wired but now think that almost everything is accidental
The scientific advisor for the book was Keith Dienes of the String Vacuum Project, and the list of those most prominently thanked for their help is dominated by landscape proponents Dienes, Bousso, Carroll and Tegmark.
A late chapter entitled “Ten Ways to Test String Theory” goes beyond the overly enthusiastic into the realm of the misleading and the simply untrue. According to Musser, the LHC will test string theory, GLAST will test string theory, Auger will test string theory, Planck will test string theory, LIGO will test string theory, a successor to Super-Kamiokande will test string theory, all the various dark-matter experiments will test string theory, table-top measurements of Newton’s law will test string theory, bouncing laser beams off the moon will test string theory, checking midget galaxies to see if their stars have planets will test string theory, and looking for variation of fundamental constants will test string theory. This is really egregious nonsense.
The next to last chapter is about “The String Wars”, and I appear prominently as “the most persistent and forceful critic of string theory”, paired with Lubos Motl for my “over-the-top” comments. One of the few explicit factual errors in Musser’s book is the claim that my book grew out of this blog (the book was written earlier, but took a long time to get published). The chapter is quite a bit less than even-handed in its discussion of these “wars”, and mainly devoted to shooting down the supposed arguments of critics of string theory. I come in for criticism as endlessly putting forward a “silly deadline” of less than twenty years for string theory to have succeeded in reaching its goals. This straw man argument is conclusively bested, while ignoring the real argument, which is that the huge investment in time and effort put into string theory research has just produced more and more evidence that string theory-based unification is an idea that doesn’t work. The problem is not the magnitude of the rate of progress towards understanding unification, it’s the sign. And, soon I can start going on about 25 years….