Today’s San Francisco Chronicle contains an article about string theory entitled “Theory of Everything” Tying Researchers Up In Knots. It’s by science writer Keay Davidson, and is about the most skeptical article on string theory I’ve seen in the mainstream press. The lead sentence is:
“The most celebrated theory in modern physics faces increasing attacks from skeptics who fear it has lured a generation of researchers down an intellectual dead end.”
Davidson contrasts Michio Kaku’s very pro-string theory point of view in his new book Parallel Worlds, with the much more skeptical views of Lawrence Krauss, who evidently has a book entitled “Hiding in the Mirror: The Mysterious Allure of Extra Dimensions” coming out in September. He also got comments about the current state of string theory from quite a few different people, including yours truly. The article contains a link to this weblog.
Some of the string theory critics quoted are just inherently opposed to any new mathematical approach to fundamental physics, something I have no sympathy with. One of these is Stanford’s Robert Laughlin, who makes the point that string theorists are trying to camouflage the theory’s increasingly obvious flaws by comparing the theory to “a 50-year-old woman wearing way too much lipstick.” Because of Laughlin’s extreme anti-mathematical theory views on the one side and those of his colleagues like Lenny Susskind on the other, “The physics department at Stanford effectively fissioned over this issue” says Laughlin. He goes on to say “I think string theory is textbook ‘post-modernism’ (and) fueled by irresponsible expenditures of money.” For the record, I’m no more of a fan of Laughlin’s views about particle theory than I am of Susskind’s.
Some of the quotes from defenders of string theory are a bit strange, with none of them addressing the fundamental problem the theory is facing these days as it becomes obvious that it can’t predict anything. John Schwarz is quoted as saying “string theory is the only approach that has the potential for explaining dark energy” which is kind of peculiar since it is well-known that superstring theory naturally leads one to expect a value for this energy density that is off by 120 orders of magnitude. The only way around this seems to be the “landscape” argument, in which you essentially give up any hope of ever predicting anything. The other defenders of string theory quoted in the article mainly try and claim that twenty years of work on the theory is still nowhere near enough, that it is way too early to be able to evaluate it yet. They don’t give any indication of how much longer we should wait for such an evaluation, but if twenty years isn’t long enough, it sounds like they hope this won’t occur while they’re still alive.
Update: For a very different take on this, see Lubos Motl’s posting.