Truth or Beauty by David Orrell

Author:David Orrell
Language: eng
Format: epub
Publisher: Yale University Press
Published: 2012-06-26T16:00:00+00:00

Supermodel

Actually, string theory is not the only exhibit on offer in the gallery of Theories of Everything. One alternative was presented by the Hawaii-based physicist/surfer Garrett Lisi in a 2007 paper called “An Exceptionally Simple Theory of Everything.” His theory views particles as being the embodiment of symmetries in the mathematical group E8 (Figure 7.4), a distant relative of SU(2) and SU(3) which is renowned by mathematicians for its “beauty” and “uniqueness” on account of its amazing range of symmetries.39 As Lisi wrote in Scientific American, “a unified theory provides a more aesthetically satisfying picture of how our universe operates. Many physicists share an intuition that, at the deepest level, all physical phenomena match the patterns of some beautiful mathematical structure.”40 The theory again predicts a range of new particles. Equally interesting are Lisi’s ideas about work/life balance: “Surfing and snowboarding are what I do for fun—to get out and play in nature. We live in a beautiful universe, and I wish to enjoy it and understand it as best I can.”41

Another approach, championed by a number of scientists including Lee Smolin and Carlo Rovelli, is called loop quantum gravity.42 This theory views spacetime as being grainy, built up from networks of small lumps joined by links—rather like a very advanced knitting project. Clusters of links turn out to share the properties of quarks and other particles. This seems an interesting approach with a different aesthetic, but so far it has not delivered in terms of testable predictions.

In the eyes of the majority of physicists, however, string theory remains the current best hope for a Theory of Everything—and it has certainly attracted the most people and research funding. John Burnet wrote that, following the Pythagorean discovery of the numerical basis for musical harmony, Greek philosophy was “dominated by the notion of the perfectly tuned string.” The same could be said today—though this might be beginning to change.

The main problem with string theory is that, like other such theories, so far it has not told us anything measurable about nature that we didn’t already know. A number of physicists therefore believe that it has become detached from reality and goes against part of the spirit of science, which insists on experiments as a reality check. In a 1985 interview, Richard Feynman said, “I don’t like that they’re not calculating anything. I don’t like that they don’t check their ideas. I don’t like that for anything that disagrees with an experiment, they cook up an explanation—a fix up to say ‘Well, it still might be true.’ … It doesn’t look right.”43 In 2003, Sheldon Glashow told PBS, “The string theorists have a theory that appears to be consistent and is very beautiful, very complex … [but] there ain’t no experiment that could be done nor is there any observation that could be made that would say, ‘You guys are wrong.’ The theory is safe, permanently safe. I ask you, is that a theory of physics or a philosophy?”44 Along the same vein,

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