This week’s New Scientist has an article promoting the string theory multiverse, starting off with positive comments from Brian Greene, and continuing with a claim that the majority of physicists now embrace the idea:
Greene’s transformation is emblematic of a profound change among the majority of physicists. Until recently, many were reluctant to accept this idea of the “multiverse”, or were even belligerent towards it. However, recent progress in both cosmology and string theory is bringing about a major shift in thinking. Gone is the grudging acceptance or outright loathing of the multiverse. Instead, physicists are starting to look at ways of working with it, and maybe even trying to prove its existence.
In his promotional book on the subject, Susskind is able to come up with exactly one bit of information that the string theory multiverse hypothesis provides, a prediction of the sign of the spatial curvature of the universe (others don’t think that even this bit is there, see this by Steve Hsu). The New Scientist article ends:
…says Susskind. “If it turns out to be positively curved, we’d be very confused. That would be a setback for these ideas, no question about it.”
Until any such setback the smart money will remain with the multiverse and string theory. “It has the best chance of anything we know to be right,” Weinberg says of string theory. “There’s an old joke about a gambler playing a game of poker,” he adds. “His friend says, ‘Don’t you know this game is crooked, and you are bound to lose?’ The gambler says, ‘Yes, but what can I do, it’s the only game in town.’ We don’t know if we are bound to lose, but even if we suspect we may, it is the only game in town.”
The arguments for string theory have evolved over the years, with the “it’s the only game in town” one being made starting fairly early on. Weinberg seems to be willing to go for a new variant of this, that not only is it the only game in town, but it’s probably crooked (i.e. can’t possibly work, is obvious pseudo-science…), and this doesn’t matter, one should continue anyway.
It has become increasingly clear to me in recent years that there is a large cohort of people who have so much invested in string theory that they will never, ever give up on the idea of string theory unification, no matter how clear it becomes that the game is crooked and not legitimate science. They will be active and with us for a long time, but the idea that there has been “recent progress in both cosmology and string theory … bringing about a major shift in thinking”, causing the majority of physicists to sign on to this is nonsense. Quite the opposite is true, with the increasingly obvious problems with string theory causing non-string theorists to shun the subject and avoid hiring anyone who works on it.
The New Scientist article is also available here, and if you want more recent multiverse promotional material, there’s this. Finally, a panel discussion on this was held at the Origins symposium at ASU recently, and is now available on-line.
Update: The torrent of string theory hype seems to continue unabated, with claims that the Planck satellite will tell us something about string theory (see here):
The results could also offer insights into the much vaunted string theory – science’s big hope for a unified theory of everything. The idea involves a complex 11-dimensional universe, with seven ‘hidden’ dimensions on top of the four observable dimensions of space and time.
Professor Efstathiou said: “The potential for fundamental new discoveries that will change our understanding of physics is very important and that is what I’m really hoping for with Planck.
“We might find signatures of pre-Big Bang physics. We might find evidence of cosmic defects – superstrings in the sky.
“Unravelling the physical information may tell us something about the warped geometry of the hidden dimensions.”