The Loose Ends of String Theory

Matt, that "spam" is relevant in the sense that false claims from string theorists about making predictions, including "string theory has the remarkable property of predicting gravity" from Ed Witten in Physics Today back in 1996, are widely hyped. The particular spam comment links to a site that claims for instance to predict quark masses by the following recipe: 1. take the measured mass of a hadron and the number of quarks it contains, plus the textbook quark masses 2. use special relativity's mass increase formula to calculate how fast the quarks need to go to produce the hadron mass (simplistically ignoring field contributions to the hadron mass!) 3. do the above by writing a visual basic program to solve the mass increase formula, to make it look clever. 4. use the calculated hypothetical quark velocities and measured mass of the hadron to get back the textbook quark masses. 5. claim that this is proof of the greatest discovery ever. I had the spam comment on my blog so I went and saw the vacuous claim, adding a comment about it. Then the guy came back with a pages long comment ignoring the science and defending himself like a string theorist defending string theory, claiming he spent $10,000 and that proves he is right, etc., plus claiming falsely that I haven't any right to edit his comment down to size, and making insults. He believes in his own theory, and mainstream string theory nonsense is the cause of this kind of crackpotism. Obviously Ed Witten uses vastly more advanced math than that spammer, but the result of string theory for actual physics is the same: it's not a theory in any sense that makes falsifiable predictions about what it claims to unify. Six extra dimensions have to be compactified in an unmeasured manifold of Planck size, so the theory has unknown parameters and describes a landscape of 10^500 or so different universes, the vaguest "prediction" in scientific history. It's then defended because people hope to use the AdS/CFT correspondence conjecture to allow calculations of QCD interactions where the force of attraction can be modelled by AdS. However, it's still a conjecture. Nobody has won a Nobel for any such QCD prediction, which wouldn't prove anything about the stringy unification theory anyway. Supersymmetry isn't falsifiable because it doesn't make falsifiable predictions; it's crackpot.