Brian Greene's The Elegant Universe is a book about string theory, the Big Think idea that is intended to finally unify Einstein's theory of relativity with quantum physics. Greene is an exceptionally clear science writer, and his initial chapters on the current state of physics (Parts I and II) are perhaps the best explanations of relativity and quantum physics that I have ever read.

His discussion of string theory--which is supposed to be the superstar of this book--starts out just as good. Basically, string theory posits that the fundamental particle of reality is a tiny, multi-dimensional string. If the funny properties of tiny, multi-dimensional strings are combined with some fancy schmancy mathematics, a lot of the weird inconsistencies between relativity and quantum physics can be made to disappear. I didn't fully understand what was going on when I finished Part III, but I was at least still interested in what else Greene had to say about the subject.

Unfortunately, about halfway through, The Elegant Universe starts getting bogged down. It's not clear to me exactly what goes wrong. Part of the problem is, no doubt, attributable to the increasing complexity of the subject matter. Because Greene can't assume that his average reader understands, say, Calabi-Yau spaces, he's forced to resort to ever more elaborate metaphors to explain just what is going on. While those metaphors work for the relatively simple theories of relativity and quantum physics, they don't work as well for string theory, which requires several sets of extremely complicated ideas (and all their associated metaphors) to be kept in one's head at the same time. So maintaining the coherence of his initial chapters might just be an impossibility.

But part of the blame is also Greene's. His initial descriptions of modern physics are good because they sketch broadly. His discussion of string theory, by contrast, becomes mired in excessive detail and jargon. This leads Greene to begin spewing sentences like, "These strong coupling characteristics of Type I string theory exactly agree with known properties of Heterotic-O string theory, when the latter has a small value for its string coupling constant," which barely makes sense unless you've been keeping careful notes. Greene also shifts from a concept-based discussion to a more chronological discussion of the development of string theory, but because every advance in string theory requires a pretty good understanding of what has already been established, the casual reader will quickly get lost.

I'm fairly confident that The Elegant Universe is the best description of modern string theory currently out there, but I get the feeling that it's not up against much. I won't hesitate to recommend it to any nonphysicist interested in physics, but be forewarned that you will be sorely tempted to give up well before the end.

Copyright © 2005 Steven Wu