This morning’s New York Times has a long and prominently placed article about the 20th anniversary of the “First Superstring Revolution”. The Times has a long history of producing overhyped uncritical articles about string theory, for a classic example, see “Physicists Finally Find a Way to Test Superstring Theory”. This one does allow some critical voices to be heard, including Lawrence Krauss, who is quoted as describing string theory as a “colossal failure” (which is different than a miserable failure)
Krauss is also quoted as saying “We bemoan the fact that Einstein spent the last 30 years of his life on a fruitless quest, but we think it’s fine if a thousand theorists spend 30 years of their prime on the same quest.”
Witten is quoted extensively, but he doesn’t sound very optimistic these days, saying “It’s plausible that we will someday understand string theory”, and making the rather weird statement that string theory is “so vast, so rich you could say almost anything about it” (for instance that it is a colossal failure?). He also seems to have given up on the idea that there is some fundamental new symmetry underlying string theory, instead putting his hopes on the existence of some new principle for constructing space and time.
The article also says that few theorists will give up on string theory when supersymmetry is not found at the LHC, with Witten interpreting this not as evidence that string theory is wrong, just that unfortunately it will be harder to get experimental evidence for it than he had hoped. String theorists in general seem to have trouble getting their minds around the idea that it is even possible the theory is wrong. Jeff Harvey does admit that sometimes he wakes up thinking “What am I doing spending my whole career on something that can’t be tested experimentally?”, but the question of “What am I doing spending my whole career on a colossal failure?” doesn’t seem to keep him awake nights.
The article ends by quoting an exchange between Steve Shenker and my colleague Brian Greene. Shenker quotes Churchill, describing the state of research into string theory as “perhaps it is the end of the beginning”. Brian seems to be one of the few string theorists around willing to actually consider the idea that the theory might be wrong, arguing that if string theory is wrong, it would be good to know this soon so physics can move on.