Resisting the supremacy of string theory

Not Even Wrong: The Failure of String Theory and the Search for Unity in Physical Law
By Peter Woit
Basic, 291 pp., illustrated, $26.95

The Trouble With Physics: The Rise of String Theory, the Fall of a Science, and What Comes Next
By Lee Smolin
Houghton Mifflin, 392 pp., illustrated, $26

Quick, explain string theory! Well, OK , string theory postulates that the tiniest, most elementary particles, the fundamental ingredients of all matter and energy, are not zero-dimensional points, as they had previously been imagined, but one-dimensional filaments that vibrate like rubber bands. When they gain energy, they stretch; when they lose energy, they contract. The vibrational state of any given string will determine how it manifests itself, as a quark, a neutrino, or some other type of particle.

Hmm. . . How did I do? Not very well? Well, guess what, it doesn't matter. Turns out, I don't have to understand string theory after all , because it's all wrong!

Well, at least according to a couple of new books. Both Peter Woit's ``Not Even Wrong" and Lee Smolin's ``The Trouble With Physics" argue passionately that string theory has played itself out. In the two and a half decades since it first captivated physicists, despite thousands of published papers and the expenditure of billions of dollars, there is no proof whatsoever that string theory is correct. Not one prediction of the theory has been experimentally testable.

`` Despite a number of tantalizing conjectures," says Smolin, a former string theorist himself, `` there is no evidence that string theory can solve several of the big problems in theoretical physics. "

Woit, a mathematician at Columbia, puts it like this: `` The problem is that superstring theory is not really a theory, but rather a set of hopes that a theory exists . "

The holy grail of physics is unification. Find a theory that unifies gravity, elementary particles, the laws of motion, and the laws that govern forces, and you may have found a Theory of Everything. Because string theory has the potential to explain both the behavior of the huge (general relativity) and the tiny (quantum mechanics), a lot of smart people continue to believe that it, or its slippery descendant, M-theory, will prove itself to be the model that unifies physical law.

But not Woit and Smolin. They argue that the physics community has over invested in string theory to the point where its single-mindedness is pulling science farther from a unified explanation of nature rather than closer to one. String theory may involve beautiful and complicated math, they say, but it should no longer be the dominant paradigm.

Are they right? Who knows? The fine points in a debate like this necessarily get quite technical, and even the most assiduous lay reader of these books may find herself lost. But maybe whether Smolin and Woit are ultimately correct is not the point.

Consider: Eight of the nine particle physicists who have won MacArthur Fellowships since 1981 have been proponents of string theory. In the physics departments of our best universities, 20 out of the 22 tenured professors are string theorists.

`` String theory now has such a dominant position in the academy, " complains Smolin, ``that it is practically career suicide for young theoretical physicists not to join the field . "

Woit says string theorists `` often seem to be of the opinion that only real geniuses are able to work on the theory, and that anyone who criticizes such work is most likely just too stupid and ignorant to understand it . "

The most compelling narrative here is not string theory vs. whatever theory might or might not supersede it. The real conflict is physicist vs. physicist. It is a human story, and an old one, involving hubris, courage, and the inertia of communal thought. You, the powerful, Smolin and Woit say, you who have staked decades and reputations on an idea, you are hijacking science.

`` The Trouble With Physics " and `` Not Even Wrong " are remarkably similar books. Woit is perhaps the more cautious writer, and Smolin is perhaps the more committed. I know it's probably more satisfying to read a book that posits a complicated, inspiring view of nature than a book that tries to dismantle one. Woit and Smolin are not Carl Sagan or Brian Greene ; they are not trying to explicate something they find rapturously beautiful. Their books are born less from a contagious enthusiasm than from a palpable frustration.

But that's not always a bad thing. Other books written for the public in recent years have tried shaking various scientific pillars: João Magueijo's `` Faster Than the Speed of Light " argued that light traveled faster in the early universe than it does now. Frank Ryan's ``Darwin's Blind Spot " argued that symbiosis, not random mutation, has been the primary engine of evolutionary change.

To take a stand against the hegemony might make you unpopular among your colleagues, but worse, it smacks of ego, because it looks like you are casting yourself as a revolutionary. Like it or not, to write a book like Smolin's or Woit's is to suggest you are akin to Galileo or Einstein, in possession of a basic truth everyone else has been missing.

But does that mean skepticism isn't valuable? `` I have little patience, " Einstein once said, `` with scientists who take a board of wood, look for its thinnest part, and drill a great number of holes where drilling is easy. "

There is always something to be respected in asking hard questions. Because isn't the seed of all good science -- and art, and government, for that matter -- courage?

Anthony Doerr is the author of ``The Shell Collector" and ``About Grace."