No small matter: is theoretical physics stuck--and should you worry?

• Author: Silber, Kenneth
• Position: Book review

The Trouble With Physics: The Rise of String Theory, the Fall of a Science, and What Comes Next, by Lee Smolin, Boston: Houghton Mifflin, 392 pages, $26

LEE SMOLIN became a physicist in the 1970s amid heady expectations that the field was on the verge of breakthrough insights into how the universe works. Theoreticians had proposed, and experimenters were verifying, the standard model of particle physics, a detailed but incomplete picture of matter and its interactions. The next step, it seemed, would be a "theory of everything," a full accounting of nature's most fundamental laws.

Three decades later, he has written a fascinating and sobering lack-of-progress report. Smolin works at the Perimeter Institute for Theoretical Physics, a think tank in Ontario; his book The Trouble With Physics combines a pungent critique of the regnant views in theoretical physics with a broader meditation on how science works, or fails to work. Its prime target is string theory, the dominant avenue of research for theoretical physicists since the mid-1980s. He argues that string theory has turned out to be a "theory of anything," an ill-defined framework that lacks explanatory and predictive power, relies on excessive conjecture, and crowds out more promising lines of inquiry.

Much more is at stake here than which faction in physics departments will have the highest success rate in achieving tenure. Physics, as Smolin points out, made steady and definitive progress in understanding nature from the 1780s until the 1980s. The field thereby demonstrated science's efficacy and helped set high intellectual standards and a confident tone for science overall. Moreover, the quest for fundamental laws of nature overlaps with longstanding philosophical and religious concerns. String theory, for instance, has become entangled in the politically charged controversy over whether the natural world bears signs of intelligent design. If theoretical physics is slowing down, or on the wrong track, scientific and intellectual life more broadly may be damaged.

And then there are the technological implications. The early 20th century's theoretical breakthroughs--relativity and quantum mechanics--paved the way for lasers, transistors, nuclear weapons, and magnetic resonance imaging machines, among other things. More recently, cutting-edge physics theories have had far fewer technological consequences. This could mean, as some scientists suggest, that physics has probed to realms so removed from the human scale as to have no practical application. But it also could mean the theories are wrong, or that the relevant technologies have not been imagined yet. Nobody in the 19th century realized that...