The story of string theory as a theory of everything has settled into a rather bizarre steady-state, with these three recent links providing a look at where we are now:
- At his podcast site, Sean Carroll has an interview with string theorist Clifford Johnson. It’s accurately entitled What’s So Great About Superstring Theory, since it’s an hour of unrelenting propaganda about the glories of string theory, save for a short mention that there had been some criticism from (unnamed) sources a decade or so ago.
The truly odd thing about the discussion though was the way it seemed frozen in time back in 1998 just after the advent of AdS/CFT duality, with almost no discussion of developments of the last twenty years. Nothing about the string theory landscape and the controversy over it, nothing about the negative SUSY results from the LHC. The attitude of Carroll and Johnson towards the failure of string theory unification seems to be to simply refuse to talk about it, and try to keep alive the glory days just after the publication of The Elegant Universe. They’ve taken to heart the post-fact environment we now live in, one where if you keep insisting something is true (string theory unification is a great idea) despite all evidence, then for all practical purposes it is true. Johnson has famously admitted that he refuses to read my book or Lee Smolin’s. As far as he’s concerned our arguments do not exist, and Carroll goes along with this by not even mentioning them.
- For the latest on the Swampland (for background, see here), there’s String Theorists’ Heads Bobble Over Potential Dark Energy Wobble, where we’re told that string theorists are claiming “huge excitement” over the possibility that string theory might make a “prediction” about dark energy. Over the years there have been endless claims about “predictions” of string theory, none of which have ever turned out to actually exist, and this is just one more in that long line. The rather odd aspect of this latest prediction is indicated by how it is described in the last paragraph of the article:
The real excitement comes from how soon we might know whether Vafa’s work has produced a testable prediction of string theory—which would be a first. Experiments like the Dark Energy Survey or the upcoming WFIRST telescope could possibly detect whether dark energy is constant or changing over time, and could perhaps do so within the next few years.
Reading this, one gets the impression that we’ll know what string theory “predicts” about dark energy just when there’s a measurement. This actually does describe what’s going on here: for some, string theory is a theory of everything as a matter of faith, so to them any new measurement tells us more about string theory, in particular that string theory “predicts” that measurement.
- Finally, there’s an article out by Thomas Hertog, which contains more about his work with Hawking that was widely advertised after Hawking’s death (see here). Hertog claims another sort of “prediction” of string theory:
String theory predicts that our universe is fundamentally a hologram that reveals itself only in the most extreme conditions, such as those at the Big Bang.
For the implications of this prediction, see String Theory Summarized.