Back in 2004, the KITP put out a press release (which I wrote about in an early blog post here) announcing that “Newly Devised Test May Confirm Strings as Fundamental Constituent of Matter, Energy”. The press release announced that Polchinski and collaborators had found “the most viable test to date for determining whether string theory is on the right track”, that this test would be performed by LIGO, which “could provide support for string theory within two years.”
This got a lot of attention and was often quoted as evidence that string theory was testable science. In a 2007 article in Physics World, David Gross answers string theory critics with:
String theory is full of qualitative predictions, such as the production of black holes at the LHC or cosmic strings in the sky, and this level of prediction is perfectly acceptable in almost every other field of science,” he says. “It’s only in particle physics that a theory can be thrown out
if the 10th decimal place of a prediction doesn’t agree with experiment.”
LIGO never found any evidence of cosmic strings within two years after 2004, and now the vastly more sensitive Advanced LIGO experiment has just released results of a search. As expected, the results are negative.
Any guess on the probability of a KITP press release announcing that string theory has failed an experimental test? Or of an acknowledgement by Gross that all the “qualitative predictions” of string theory he was using to justify it ten years ago have now all failed, so, by the standard of “every other field of science”, it should be abandoned?