Not Even Wrong

Last week the Perimeter Institute ran a Workshop on Cosmological Frontiers in Fundamental Physics and someone wrote in to point out to me that the talks are now available on-line. Much of the workshop was about mainstream cosmology, especially the more speculative ideas about inflation and what signals might be found in the CMB.

The particle physics component was heavily weighted towards Landscapeology (talks by Denef, Kachru, Kleban), with a workshop-ending talk entitled “50 Years since the LHC” by Nima Arkani-Hamed. Arkani-Hamed’s talk was supposed to be a prediction of what things would look like 50 years after the LHC, and he ended it with the prediction that “the LHC will put the last nail in the coffin of mono-vac theories” and that “the Landscape will be with us to stay”. Along the way he went over various possibilities for what the LHC might see and their implications for whether the cosmological constant and the weak scale are anthropically determined. He said that he believed the cosmological constant was anthropically determined, and half the time he thought the weak scale was too, the other half of the time he thought it wasn’t. He argued for giving up on coming up with new mechanisms for electroweak symmetry breaking since “working on the (N+2)nd variant on the (N+1)st model of EWSB is not worth it”, saying that instead people should participate in the LHC Olympics and work on the “inverse problem” of figuring out from LHC data the 105 parameters of the MSSM or some other model of beyond standard model physics.

Near the beginning of his talk he gave a graph representing (as a function of time) the average string theorist’s view of the probability that string theory could be used to calculate standard model parameters. This started out near 1 in 1985, dropping to a small number in 1995 after the duality revolution showed that strongly coupled strings didn’t get rid of the wide range of possible backgrounds, and further dropping to “a number close to the fine tuning of the cosmological constant” in 2000 after the advent of the Landscape and the non-zero cosmological constant. The same graph also included a plot for the views of “clueless popularizers and science journalists”, which had only recently started to head down slightly from 1. He claimed that such people are ten years behind the times and that it is “not going to be pretty” when they catch up with the current views of string theorists and realize the theory can’t predict anything.

While at Perimeter, (according to Lubos Motl) Arkani-Hamed was talking to LQGer Laurent Freidel about Doubly-Special-Relativity in three dimensions. It’s going to be a lot of fun to watch what Lubos has to say if and when some of his senior colleagues start working on LQG, something that seems entirely possible since string theory is now moribund, whereas LQG is in a much livelier state.

Landscapeology still seems to be making headway at taking over particle theory and ensuring that it becomes a pseudo-science. If you’ve got $250 and can get to an access grid facility, next week you can participate by video conferencing in a workshop at Ohio State on Strings and the Real World, which will have one day out of three devoted to the Landscape. I would have thought the title of the workshop would get into trouble with false advertising laws, since one thing that is clear is that absolutely none of the talks will be even slightly relevant to the real world.

For a horrific vision of where particle theory is headed, check out the website of the String Vacuum Project. The idea seems to be to get particle theorists spending their time developing software to do numerical computations searching amongst the infinite variety of the Landscape to find something or other. The section of the web-site on the connection of any of this to real particle phenomenology remains to be written.

The latest Cosmic Log column on msnbc.com concerns Lawrence Krauss’s new book Hiding in the Mirror and the author asked Krauss a question I’m expecting that physicists will be hearing more and more often as time goes on: “Why is string theory science but intelligent design isn’t?”

Krauss gives a response that isn’t completely convincing. He says that “the difference is that Ed Witten and the other good string theorists will, if an experiment comes along that demonstrates that supersymmetry isn’t discovered in a definitive way, be the first to say the theory is wrong.” This isn’t really true. Since the scale of supersymmetry breaking is unknown, one can’t hope to experimentally definitively show supersymmetry is not there. And the question at issue is string theory, not supersymmetry. Will string theorists abandon the theory when supersymmetry is not found at the LHC? We’ll see in a few years, but I already see them hedging their bets and many undoubtedly will not see the lack of supersymmetry at LHC energies as proving string theory wrong.

The behavior of string theorists that Krauss identifies as most like religion is the argument that “the theory is so beautiful it must be true.” I actually don’t hear many string theorists making this argument these days. If the theory actually were beautiful in the sense of providing some impressive new understanding of physics in terms of some simple, compelling mathematical or physical idea, that actually would be a good reason for believing in it, although not a completely conclusive one. All attempts so far to connect the theory to real physics lead to hideously complicated and ugly constructions. Some string theorists such as Susskind, argue that one should believe in string theory anyway, and it is this argument which seems to me to be more like religion than science. It’s my impression that Susskind and others are believing something for sociological and psychological reasons, something for which they have no rational, scientific argument. This behavior is not distinguishable from that of many of the intelligent designers, and if it becomes more widespread it ultimately threatens to do real damage to the public perception of science in general and theoretical physics in particular.

Krauss gets closer to the real difference between string theorists and intelligent designers when he says that string theorists “are trying to come up with predictions that actually do something”. More sensible string theorists are well aware that what they are doing isn’t going to be part of science until they figure out a way to use it to make real predictions that can be tested. In general, given a new speculative idea, it will not be obvious how to figure out all of its implications and see whether it can lead to real predictions. It can take years of work for this to become clear, and this sort of work is definitely science. On the other hand, if after a lot of work, there still is no indication that an idea can produce predictions, the continued pursuit of it at some point stops becoming science and starts becoming something more like religion. Susskind and other anthropic landscapeologists have already gone past this point: they have no plausible idea about how to ever get real predictions out of their framework. String theorists who argue that the theory is still too poorly understood, that more work is needed to understand whether there is some way around the radical non-predictivity implied by the landscape, are nominally still doing science. But at some point, as years pass without any progress in this direction, and evidence mounts that hopes for ways to get predictions aren’t working out, this activity stops being science and it too starts being a non-scientific activity pursued for sociological and psychological reasons. We’re close to that point, if not already past it.

Update: There’s a defense of string theory against the charge that it’s like intelligent design over at Kasper Olsen’s blog. I don’t find it very convincing, since it doesn’t address at all the question of how string theory is ever going to do what a real science is supposed to do: make falsifiable predictions. Much of Olsen’s list actually strikes me as a recitation of a catechism of supposed reasons why string theory is so wonderful, rather than a serious scientific argument. Some of these are also highly dubious (e.g. “the Standard Model can be reproduced in a very simple way”), they’re things that one has to be a true believer to say, since they really don’t accord with reality.

One commenter (Gavin), gave a very good reason for distinguishing string theory from intelligent design: “the former is trying to explain something that is already explained, while string theory is trying to solve a mystery” and he correctly notes that while string theory’s scientific credentials may be weak, the problem is that there aren’t really good alternatives (LQGers may argue with this…). John Baez’s comment about the relationship of math and physics was also quite nice.

Sir Michael Atiyah is here in the United States this month. Evidently he was at the Institute in Princeton last week during the Deligne conference, talking to Witten. Last Friday he gave a public talk at an AMS conference at the University of Nebraska on The Nature of Space, and will be giving another one tomorrow in Santa Barbara on the same topic.

Yesterday at the KITP he gave a talk on his own very speculative ideas about physics entitled Does the Universe Have a Memory?. He began by subtitling his talk “Crazy thoughts of an old man”, and noting that when he was at the Institute Witten had listened to him politely and then after a micro-second given him four reasons why his ideas wouldn’t work. One motivation he gave was that the current situation of string theory was somehow like Ptolemaic epicycles, with a fundamental idea that would drastically simplify everything still missing.

The speculative idea he was promoting was that perhaps quantum mechanics should be changed so that the future depends not just on the present, but on the history of the system during some short period before the present. So dynamics would be somewhat non-local in time. He hopes for some connection to the Connes version of the standard model, but this was all very vague. All in all, I fear that I wish Atiyah would go back to working on the relation between K-theory and physics….

Update: In a comment Doug provides a link to Atiyah’s public lecture.

There have been several recent interesting talks at the KITP in Santa Barbara as part of their program this semester on Mathematical Structures in String Theory. Last week Greg Moore gave a beautiful talk on Mathematical Aspects of Fluxes. It’s a sad commentary on the state of the field that he felt it necessary to begin his talk by apologizing that the work he was describing didn’t seem to have anything useful to say about the Landscape.

This week Graeme Segal spoke about On the Locality of the Statespace of Quantum Field Theory. He is trying to understand the right way to axiomatize the way in which the Hilbert space of a QFT depends on the boundary of space-time in a local fashion. In his talk he worked out things for the case of a free scalar on an arbitrary manifold. Also this week, Peter Teichner and Stephan Stolz spoke on their work on generalized cohomology and QFT, motivated by trying to understand the relation of elliptic cohomology and conformal field theory. Teichner gave the first part of the talk on Tuesday, Stolz gave the second part on Thursday. For more about their work, see some earlier comments of mine, their paper What is an elliptic object?, and an earlier survey talk by Teichner at the KITP.

The latest issue of Nature has an essay on Hermann Weyl by Frank Wilczek. The essay mainly advertises Weyl’s book Philosophy of Mathematics and Natural Science, originally published in 1926, but updated for the English translation in 1949. I’m embarassed to say I’ve never read this, despite my fascination with Weyl, so I guess I better go out and get ahold of a copy.

Yesterday I went down to the Institute in Princeton with my friend Oisin McGuinness to attend one day of a conference in honor of Pierre Deligne that is going on there this week. Deligne has spent most of his career at the IHES and at the Institute, and this conference was in honor of his 61st birthday (I suspect they initially planned it for last year, but it got pushed back).

Deligne worked with Grothendieck at the IHES during the late sixties, and is perhaps best known for his proof of the Weil conjectures completed in 1974, an achievement which won him a Fields medal in 1978. The Weil conjectures motivated much of the work by Grothendieck and others in algebraic geometry during the fifties and sixties, and Deligne was able to finish a proof using Grothendieck’s machinery as well as some different ideas of his own. For more about Grothendieck, visit the Grothendieck Circle web-site. Grothendieck left the IHES around 1970, and later became a recluse, increasingly hostile towards his former colleagues, especially Deligne, who he attacked in his long unpublished manuscript “Recoltes et Semailles.” Several people told me that at the conference banquet held Tuesday night, after an array of different speakers rose to praise Deligne, especially for his generosity with his ideas and help to others, Deligne himself spoke and said that he was only repaying the debt he owed to Grothendieck, who himself was famous for such generosity.

One of the conference talks I heard was by Gerard Laumon, who described some of his work with Ngo Bau Chau on the Fundamental Lemma. Various lecture notes on this subject are available here. Laumon emphasized the role of equivariant cohomology in the proof, a method pioneered by Goresky, Kottwitz and MacPherson. Equivariant cohomology techniques are also crucially behind much work on topological quantum field theory, although of course the context is quite different there.

To some extent, if one wants to understand some of the recent history of physics, one should take into account important demographic trends in the subject. For particle physics in the U.S., in recent years the Particle Data Group has been conducting an annual Census of U.S. Particle Physics. The American Institute of Physics has a collection of reports available on-line. The NSF and other various other organizations periodically issue hysterical reports about there being too few physics students getting Ph.D.s. For some perspective on this, in 2003 there were a bit more than 1100 physics Ph.D.s awarded in the U.S., and during 2001-2002, about 230 retirements per year of permanent faculty. Due to large recent increases in graduate student enrollment, the number of Ph.D.s is expected to increase significantly during the next few years. There doesn’t seem to be much danger that anytime soon U.S. universities will see any change in the current situation of having vastly more qualified candidates for academic jobs than actual permanent jobs available.

In the specific case of particle theory, the Particle Data Group figures show roughly 450-500 tenured faculty, and 400-450 graduate students. So, the entire U.S. tenured particle theory professoriate could be just about replaced by one 4-5 year cohort of graduate students. The theoretical particle physics job market will remain extremely competitive for the forseeable future.

Unfortunately, the main hope for young physicists who want an academic job is that current tenured faculty are getting old and have to retire or die sooner or later. The latest data I’ve seen (from a 2000 AIP membership survey) indicated that the average age of tenured physics faculty had reached nearly 60. If anyone knows of more recent data I’d be interested to hear about it. I don’t know of any good on-line sources for historical data, but the December 1995 issue of Physics Today had an interesting article about demographic trends in physics entitled “What future will we choose for physics?”. The authors of that article claimed that before 1970 the median age of physics professors in the U.S. was relatively stable and under 40. In 1970, the number of physics Ph.D.s awarded hit an all time high of nearly 1600, and faculty hiring essentially fell off a cliff. According to the Physics Today article, from 1970 on the median age of tenured faculty increased linearly at the rate of about 8 months/year.

One effect of the aging of the physics community is that Physics Today has been running an increasing number of obituaries, since it has a long-running policy of printing a picture and several paragraphs about each of their members for whom obituaries are submitted. As of this month, facing the prospect of having to devote an increasing fraction of space to this purpose, they have abandoned this policy, announcing that from now on they will only publish obituaries in special cases, setting up a separate web-site for on-line obituaries, since these won’t be appearing in the magazine itself.

Update: Andre Brown wrote in to point out that the 1995 Physics Today article is available on-line.

This week there’s a large conference in Potsdam on non-perturbative/background independent quantum gravity called Loops ’05. The programme is on-line, and there is live-blogging from Robert Helling.

Update: String theorist Robert Helling has more coverage of the conference. This includes the hilarious criticism (quoted approvingly by Jacques Distler) that too many of the talks were “so vague and speculative that they are not even wrong.” Helling does notice that the string theorist speaker (Stefan Thiessen) delegated to talk about what is going on in string theory had nothing to say, and just repeated the failed dogma from more than 20 years ago. Maybe at Strings 2006 they’ll even let someone from the LQG camp speak, or at least there will be live-blogging from an LQGer.

Note: This is a reconstruction of my original posting. Unfortunately I accidentally hit the wrong button when trying to edit a typo in a comment, deleting the posting and all comments. Thanks to Steve and Aaron for helping me retrieve the content of the posting, but unfortunately most of the comments were lost. If you have copies of them, please send them to me or resubmit them yourself.

Update: For something truly bizarre, see Lubos Motl’s comments on Loops ’05, where he attacks the talks there as “not even wrong”, while in the same posting respectfully reporting on a talk by Cumrun Vafa at Radcliffe on the Swampland, a talk at which several people evidently expressed the opinion that it could never lead to an explanation of anything about physics.

Update: There’s a bit more about Loops ’05 in the latest issue of John Baez’s “This Week’s Finds”.

Update: The talks from the conference are now on-line.

A commenter here wrote in to point out that Margaret Wertheim, a science columnist for the Los Angeles Times, has a new piece entitled Physics strings us along. She discusses Lisa Randall’s new book as an example of physics that has become completely unmoored from empirical evidence and instead “has become in effect a form of speculative literature” (much like John Horgan’s characterization of this sort of thing as “science fiction in mathematical form”). Wertheim notes that it is becoming hard to distinguish theoretical physics from religion and magic, supposedly less rational practices, claiming that “in recent years science itself has been showing increasingly magical tendencies”, concerning itself with “entire landscapes of universes for which there is no empirical evidence whatever. ”

She is writing a book about “the role of imagination in theoretical physics”, and she seems overly enthusiastic about how “Unchained by the fetters of verification, string theorists are free to dream, articulating through their equations vast imagined domains in which almost anything that is mathematically possible is deemed to be happening ‘somewhere.'”