Physics Quote Of The Day

String theory is a living proof of the dangers of excessive reliance on non-empirical arguments. It raised great expectations thirty years ago, promising to compute all the parameters of the Standard Model from first principles, to derive from first principles its symmetry group SU(3)×SU(2)×U(1) and the existence of its three families of elementary particles, to predict the sign and the value of the cosmological constant, to predict novel observable physics, to understand the ultimate fate of black holes, and to offer a unique, well-founded unified theory of everything. 

Nothing of this has come true. String theorists, instead, have predicted a negative cosmological constant, deviations from Newton’s 1/r^2 law at sub-millimeters scale, black holes at the European Organization for Nuclear Research(CERN), low-energy super-symmetric particles, and more. All this was false. 

Still, Joe Polchinski, a prominent string theorist, writes that he evaluates the Bayesian probability of string to be correct at 98.5% (!). This is clearly nonsense.

Carlo Rovelli in a paper at a December 2015 string theory conference in Munich, via Not Even Wrong, which also notes that the probability claimed was actually "three sigma" (99.73%), and that with regard to a contribution from physicist Gordon Kane: "As usual with Kane, there’s a string theory “prediction” of the gluino mass (1.5 TeV +/- 10-15%) which has already been falsified."

The situation has not improved in the three years that have elapsed since this conference, although the tides of educated public opinion do seem to be shifting, ever so slightly.