Physicist/surfer Garrett Lisi may have come up with a physics theory that unites all the fundamental particles and forces of nature, including gravity, without relying on dubious multidimensional string theory. According to this related article:

…[H]is proposal is remarkable because, by the arcane standards of particle physics, it does not require highly complex mathematics.

Even better, it does not require more than one dimension of time and three of space, when some rival theories need ten or even more spatial dimensions and other bizarre concepts.

In other words, it doesn’t require invoking arbitrary new dimensions for which we have no evidence. Plus it makes testable predictions that are at variance with the so-called Standard Model. The New Scientist article states that his theory predicts:

…[M]ore than 20 new particles not envisaged by the standard model. Lisi is now calculating the masses that these particles should have, in the hope that they may be spotted when the Large Hadron Collider – being built at CERN, near Geneva in Switzerland – starts up next year.

“This is an all-or-nothing kind of theory – it’s either going to be exactly right, or spectacularly wrong,” says Lisi. “I’m the first to admit this is a long shot. But it ain’t over till the LHC sings.”

David Harriman mentioned in his lecture to our Front Range Objectivism group last year that any physicist who wants to challenge the dominance of string theory will have a very hard time, since nearly all the grant funding in academia for such foundational issues is controlled by people who believe in string theory. It seems that this is borne out by Lisi’s experience, as reported by New Scientist:

Most attempts to bring gravity into the picture have been based on string theory, which proposes that particles are ultimately composed of minuscule strings. Lisi has never been a fan of string theory and says that it’s because of pressure to step into line that he abandoned academia after his PhD. “I’ve never been much of a follower, so I walked off to search for my own theory,” he says. Last year, he won a research grant from the charitably funded Foundational Questions Institute to pursue his ideas.

For those who are interested in the details of his theory, here’s the link to his paper (click on “PDF” on the upper right). The abstract reads as follows:

An Exceptionally Simple Theory of Everything

A. Garrett Lisi (Submitted on 6 Nov 2007)

Abstract: All fields of the standard model and gravity are unified as an E8 principal bundle connection. A non-compact real form of the E8 Lie algebra has G2 and F4 subalgebras which break down to strong su(3), electroweak su(2) x u(1), gravitational so(3,1), the frame-Higgs, and three generations of fermions related by triality. The interactions and dynamics of these 1-form and Grassmann valued parts of an E8 superconnection are described by the curvature and action over a four dimensional base manifold.

Those who want a semi-technical explanation (with video) can find one here. My own mathematics background is not strong enough to make an assessment of the merits of his theory. Nor do I know any more about the Foundational Questions Institute besides what’s on their webpage. But for what it’s worth, I did meet Garrett Lisi at a dinner party several years ago as a friend-of-a-friend, back when Diana and I lived in San Diego and he was still a graduate student in physics at UCSD. At the time, he struck me as an extremely intelligent man, so he would be a plausible candidate for someone who could have come up with a revolutionary new theory in physics.