Every year John Brockman’s Edge web-site hosts responses to a different question. This year the question was What scientific idea is ready for retirement?. It shouldn’t be too hard to guess what I chose to write about, with results available here.
Every year Brockman manages to attract more responses, so this is now getting to be a statistically significant sampling drawn from the population of people who write about science for the general public. Before trying to divine some general trends among the physics responses, I’ll first mention a few of them that stand out as unusual.
First, there’s one from Paul Steinhardt that I very much agree with. He’s had it with the multiverse and thinks it needs to go. I’m very glad to see someone else making many of the points that I endless repeat on this blog in a tiresome way. So, go read what he has to say, which ends with this challenge to the theoretical physics community:
I think a priority for theorists today is to determine if inflation and string theory can be saved from devolving into a Theory of Anything and, if not, seek new ideas to replace them. Because an unfalsifiable Theory of Anything creates unfair competition for real scientific theories, leaders in the field can play an important role by speaking out—making it clear that Anything is not acceptable—to encourage talented young scientists to rise up and meet the challenge.
It would be great to see someone other than him and David Gross start publicly speaking out.
A second outlier is Gordon Kane, who uses this as an opportunity to claim that he had predicted the Higgs mass using string theory. I don’t know of anyone other than him who takes this seriously. He doesn’t mention his other string theory based predictions, which include the prediction that the LHC should already have seen gluinos.
Another odd one is from Max Tegmark, who argues that we have to get rid of equations in physics that aren’t just based on finite and discrete quantities. The only positive argument I can see from him for this is that it would help get rid of the “measure problem” of the multiverse, but listening to Steinhardt and dumping the multiverse itself seems to me a much better idea. Tegmark has a new book out, I’ll write more about this here in a few days.
Another theme is people starting to sound like John Horgan, announcing we’re reaching the limits of science. Martin Rees thinks that some scientific problems may never yield to our understanding: “The human intellect may hit the buffers”. Ed Regis thinks the cost of a next generation collider is just not worth it for what it is likely to tell us.
A variant of this is the argument that we’ve reached the end of the road for unification and simplicity in our basic physical laws. Here the argument often seems to be that since SUSY/GUTs/string theory were such beautiful elegant ideas, their failure means the whole elegance thing is misguided. Another point of view (which I think someone wrote a book about) would be that these always were heavily oversold as “elegant”, since if you looked into them they were rather complicated and didn’t explain much. Writing in the anti-elegance vein are experimentalist Sarah Demers:
It is time for us to admit that some of the models we have been chasing from our brilliant theory colleagues might actually be (gorgeous) Hail Mary passes to the universe.
along with Marcelo Gleiser and Gregory Benford. At this particular time in intellectual history, it seems that hardly anyone has anything good to say about mathematical elegance as a powerful principle behind deep ideas about physics.
Finally, the biggest contingent are the multiverse maniacs. There’s Andrei Linde, who deals with the problem of evidence for his ideas by:
A pessimist would argue that since we do not see other parts of the universe, we cannot prove that this picture is correct. An optimist, on the other hand, may counter that we can never disprove this picture either, because its main assumption is that other “universes” are far away from us.
He’s joined by Sean Carroll, who wants to do away with the Popperazi and their inconvenient demands for falsifiable predictions. Also writing in support of the idea of a multiverse of different physical laws, implying we’ll have to give up on the idea of understanding more about the ones we see are Lawrence Krauss and Seth Lloyd.
Update: A couple more late additions that I missed. Eric Weinstein is with me in going after “string theory is the only game in town” as something that should have been retired long ago. Alan Guth uses this venue to promote some recent speculative work on the arrow of time with Sean Carroll (no paper yet, so hard to tell what it really is).
Update: Sean Carroll has a blog posting up about his argument for getting rid of falsifiability. He seems to not be getting a lot of support, either in his comment section (see for instance here), or places like here. I don’t think the skeptic community is ready to disarm itself intellectually in arguments against religious believers by ditching the conventional scientific method.
Update: Scott Aaronson writes here about the falsifiability issue, pointing out about string theory/multiverse research that
I wouldn’t know how to answer a layperson who asked why that wasn’t exactly the sort of thing Sir Karl was worried about, and for good reason.
Sean Carroll responds that the problem here is
somber pronouncements about non-falsifiability from fuddy-duddies.