In Monday’s London Times there’s a piece by Anjana Ahuja about my new book and the controversy over string theory. Ahuja worries that I might have multiple spleens, so I want to reassure her and others that I only have one, generally of normal size. I suppose that at times when dealing with Lubos, it may get a bit enlarged.
Ahuja gives a reasonably good account of some of the heated debate going on about string theory, but does get one thing wrong about my point of view on this, when she sets me up as someone who argues that “aesthetics is no substitute for experiment” in contrast to Brian Greene’s emphasis on “The Elegant Universe”. This is an issue where I’m with Brian, unlike, say, Lenny Susskind. I firmly believe that this is an elegant universe and that the pursuit of more mathematically elegant theories is our best hope for moving forward. I just don’t happen to think that the kind of string-theory based unification ideas that people have been pursuing are especially mathematically elegant.
Ahuja also remarks on the fact that Brian and I work in the same department but I don’t thank him in the acknowledgements. There’s no big mystery about that, I just haven’t had any really substantive conversations with Brian about the topics of the book, so didn’t explicitly thank him there. Brian is a very nice guy who I first met when he was a graduate student. He came to Columbia about ten years ago, hired by the math department with a joint appointment in physics. During the past few years, unfortunately for the math department, Brian’s interests have shifted from mathematics more towards physics and he spends most of his time over in the physics department, where he has started up a successful new research institute called ISCAP.
I’ve often helped him with computer problems, and last time I saw him a week or so ago in the hallway, he congratulated me on the book, which he had just gotten a copy of from the publisher, and said he was looking forward to reading it. I warned him he might not like some parts of it at all, he said that was fine, controversy and debate was good, or something like that. Basically, he and I disagree about a scientific question: can one make a successful unified theory out of string/M-theory? I think there are good reasons to think one can’t, he’s still optimistic that it might work out.
Brian is far from the only string theorist I know who I have this disagreement with. Some are very good friends that I’ve debated with extensively about this, others, like Brian, I don’t happen to have spent much time discussing the topic with. But disagreements over whether some speculative idea can ever work are not unusual in science, and most scientists have no problem with healthy debate of this kind. I’ve found it extremely surprising and disturbing that a small number of string theorists have chosen to engage in personal attacks rather than the usual sort of scientific debate.