In this thread I mentioned a talk about string theory that was on at the Planetarium in NYC last night, by Lee Smolin. (Apparently it will be put on a podcast at the NYAS "Science and the City" podcast site eventually).
I attended the talk. Smolin is basically a sort of physics gadfly, although he clearly appreciates and reveres many of the people involved, he sees it as his mission to point out difficulties they are having.
He thinks that the lack of new developments in physics (in particular, uniting quantum mechanics with Einsteinian general relativity) amount to a sort of crisis. Although string theory is held out as a possible solution to the problem, clearly it hasn’t been confirmed by experiment, and Smolin pointed out that there are a very large number of possible ‘string theories’.
He also introduced a number of competing theories (e.g., ‘loop quantum gravity’, et al.) that he feels are getting short shrift around the physics table, as they are at least as promising as string theory at potentially uniting QM and relativity.
This is all very good and interesting.
I had a few problems though. First of all, as I mentioned in the prior thread, it seems that a public lecture is the wrong place to air this sort of intra-scientific dirty laundry. Not to say there isn’t a problem here, but rather that us ignorant outsiders aren’t going to be able to adjudicate which is the problematic party ... we’re just waiting for the evidence, as in experimental confirmation or disconfirmation. All the talk of competing theories is so much hot air until they are confirmed or disconfirmed.
Secondly, Smolin reiterated many times that physics was in ‘crisis’ because it had gone 70 years since the last great breakthrough. This just seemed to me a bad argument. To start with, physics as a unified discipline only goes back about three centuries to Isaac Newton, so the sample size is way too small to make such claims. Also, part of Smolin’s argument about the problems of physics were that dark matter and dark energy were unexplained ... yet the discovery of dark matter and dark energy were made in the last decade or so, which sounds to me like at least cosmology isn’t in crisis, it’s making wonderful discoveries. Also, who says that physics has to develop uniformly? There was quite a long time between Newton and Einstein ...
Thirdly, Smolin relied inconsistently on some very bad philosophers of science ... but that’s more of a question that would be of interest to professional philosophers than physicists.