A colleague of mine, an expert on the foundations of quantum mechanics, recently gave a public lecture at our college called "Quantum Mechanics for Everyone." Afterward, another colleague, not a scientist, said of the talk: "I understood, but I'm not sure what I understood." Many readers of Lee Smolin's Three Roads to Quantum Gravity may have the same reaction.
Smolin, professor of physics at Pennsylvania State University, succeeds at giving us what reviews of similar books have called "an illusion of understanding." We read his description of the cutting-edge search for an ultimate theory of reality, we take aboard his metaphors, we digest his anecdotes, and we have a feeling that we understand what he is talking about. Even that is a triumph--for us and for Smolin. The subject of this book is so highly abstract, and so far removed from ordinary experience, that an illusion of understanding is perhaps the best we can hope for.
This article was originally published with the title A Spin on Spin Foam.