So when Stephen Shenker, a Stanford University theorist who was moderating a panel discussion here on the future of the putative theory of everything, asked for a show of hands on the fate of a strange number known as the cosmological constant, some 400 physicists and mathematicians were happy to swallow their doubts and vote.

The panel discussion, titled "The Next Superstring Revolution," took place at Strings05, the latest yearly congress of string theorists, held in mid-July at the University of Toronto. That it was a somewhat unusual occasion was not lost on anyone. No other field of science, said Jacques Distler, from the University of Texas, would be presumptuous enough to have a meeting about its next revolution.

But then no other field of science is like string theory, which says that nature with all its forces and particles is composed of tiny strings wriggling in 10 dimensions. In the last two decades it has taken academia by storm, and it has been rocked by periodic reinventions.

The first happened in 1984 when it was shown that a consistent theory of all the forces of nature could be constructed from strings. The second occurred in 1995 when relationships between the five different kinds of string theory suggested that they were all separate manifestations of a single underlying 11-dimensional theory known as M-theory.

As a result, string theory conferences have often been the scene of drama and, one year, even dancing and singing, when new developments rocketed the field into new dimensions of their mathematical wonderland.

But despite success in formulating a mathematically consistent theory that unifies gravity and the rest of nature, a goal that eluded Einstein, progress has stalled on other fronts, like going beyond consistency to proving that string theory is actually right. One problem is that "stringy" effects manifest themselves only at energies orders of magnitudes beyond the capabilities of any particle accelerator that could be built on Earth, meaning that the theory cannot be tested or guided by experiment.

"We've done very well for the last 20 years without any experimental input," said Michael Douglas of Rutgers.

Some string theorists (there are no string experimentalists) hope they might get some help soon. In 26 months, the most powerful particle accelerator ever built, the Large Hadron Collider, or L.H.C., will begin colliding protons with energies of seven trillion electron volts apiece at CERN in Geneva.

One long shot is that the accelerator will find evidence of particles disappearing into the extra dimensions demanded by string theory, which Dr. Douglas said would be "one of the great triumphs of human history."

Nima Arkani-Hamed, a Harvard physicist, called the Large Hadron Collider "an unprecedented opportunity for discovering new physics."

But, he said in a talk here, there is a problem. What physicists most expect to discover with the Large Hadron Collider is a new phenomenon called supersymmetry (which would manifest itself as a passel of new particles). Supersymmetry is predicted by string theory but alas is not exclusive to it. In fact there are tens of thousands of different models of supersymmetry, he said, so many that physicists will have trouble figuring out which one is right from a given set of data.

To dramatize the problem, Dr. Arkani-Hamed and others have prepared a simulated set of data from the collider and challenged their colleagues, in what they have dubbed the L.H.C. Olympics, to figure out what it means. For those who want to play, more information is available on the Web site http://wwwth.cern.ch/lhcOlympics/lhcolympics.html.

The panel discussion on the next revolution attracted a full, if somewhat dubious crowd. One of the panelists, Eva Silverstein of Stanford, joked when her time came that her friends in high-energy physics were amused "when we sit around and tell about our feelings."

Dr. Shenker, a Stanford theorist who has tousled blond hair going gray, was drafted as moderator by the organizers, so the joke went, because he "was not only respected, but feared." He had recruited his panel with an accent on youth, on the ground that the progenitors of the previous revolutions were unlikely to be the makers of the next.