Panel Discussion Video

Video of the panel discussion at Toronto is now available, so one can hear some of the context of the comments that were reported in the recent New York Times article. As reported, the audience voted 4 or 5 to 1 against the anthropic principle. Unfortunately the camera was not on the panel during the vote, so one can’t tell from this video how the panelists voted.

Some other things that weren’t reported: while Andy Strominger commented that he saw no reason for pessimism, he also said he thought the odds were against any data relevant to quantum gravity or string theory coming out of the LHC. Steve Shenker said that he was very much bothered by the fact that it was starting to look as if one could associate some sort of “quantum gravity” dual to any quantum mechanical system whatsoever, so any notion of uniqueness was completely gone.

There were several skeptical questions from the audience. Someone with a Russian accent pointed out that it was becoming increasingly difficult to argue the case for string theory in the physics community, and asked what argument he should use in its favor. The panel didn’t seem to want to address this, but Shenker finally said “Only consistent theory of quantum gravity”. The next question wasn’t really audible, but had something to do with “it’s been 20 years”. Shenker’s response was something like “most of us don’t want to think about this, we haven’t done as well as in other 20 year periods”. Later on someone asked “Can you imagine any experiment in the next 20 years that will falsify string theory”, getting no real response except “You’re not supposed to be asking that” from Shenker. Another question from the floor was about why none of the panelists had mentioned M-theory, which didn’t get much of an answer except from Nathan Berkovits who commented that in particle theory problems not solved in five years stop being discussed.

In their speculation about the future, many of the panelists invoked the possibility of having to change quantum mechanics. From the floor Witten speculated that quantum mechanics was only valid in asymptotic regions of space time, with something different needed to understand the interior. Also from the floor Susskind speculated that the splittings into different universes of the many-worlds interpretation of quantum mechanics were the same as the cosmological bubbling off of different baby universes. Several panelists responded that they had no idea what he was talking about.

The emphasis on vague ideas about the foundations and interpretation of quantum mechanics led Martin Rocek to point out that there was one field of study in physics that had gone nowhere in the last eighty years: the study of the interpretational issues in quantum mechanics. Lee Smolin rose to the defense of this field, claiming that it had led to recent ideas about quantum computers.

Also now available online are videos of the public talks by Dijkgraaf and Susskind. Susskind tells the audience that there is a “War” or “battle of intellects” going on between two groups of physicists, which he describes as being “like a high-school cafeteria food fight”. The two groups are the “As” (A for anthropic), and the “Es” (E for elegant). He describes the belief by the Es in mathematical elegance as “faith-based science”, and says that they are in “psychological denial” about the existence of the landscape, then goes on to give the standard arguments for the landscape and the anthropic use of it to “explain” the value of the cosmological constant. He refers to belief in the existence of a vacuum selection principle as analogous to belief in the Loch Ness monster. He ended his talk by claiming that the As were winning the war, with the Es in retreat.

Dijkgraaf’s talk was completely standard string evangelism, and except for a couple slides mentioning D-branes and black holes, could easily have been given, completely unchanged, twenty years ago.

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69 Responses to Panel Discussion Video

  1. cvj says:

    Garrett, I’m puzzled and saddened. Why is there a need for a group blog speaking out against string theory? Is there a group blog out there speaking out in favour of string theory? No. There are maybe three sites that are dedicated to regularly discussing results in string theory, and other blogs (such as cosmicvariance) that has some discussion of strings from time to time, none devoted to promoting any particular theory – there are certainly no group blogs of that nature.

    You’re promoting the business of doing science by seeing who can shout the loudest? That’s very sad. Wouldn’t it be better to form a blog to do something positive where you might often calmly and rationally discuss the alternatives approaches to string theory, rather than existing purely in opposition to something? Come on. Let’s not demean ourselves as a community in this way.


  2. Gordon says:

    I agree, Garrett, there is no need for another blog, especially
    another site speaking against the string theory, however important
    that it is.

  3. cvj says:

    By all means have another blog. Just have it for positive reasons, not negative ones. -cvj

  4. simplex says:

    here is Garrett’s original suggestion posted 9 Aug around 11PM

    Hey Peter,
    Have you considered starting a group weblog for physics phd’s who don’t like string theory and are actively pursuing alternatives?

    I dont think such a blog, of people doing Quantum Gravity alternative to string, would necessarily “demean us as a community” as Clifford evidently fears.

    I can see why Peter would not want to set up such a blog, it would have to be set up by one or more people who are ACTIVELY PURSUING ALTERNATIVES on a professional basis. One or more postdocs or young faculty who are involved with the main nonstring lines of QG research.

    It would be better, if there were going to be one, for it to be set up by someone like Etera Livine who is a postdoc at Perimeter engaged in
    nonperturbative/backgr. indep. QG, also possibly in quantum computing.

    Maybe if Livine happened to be friends with Willem Westra or Dario Benedetti (both at Utrecht) they could set up something like “Nonperturbative Coffee Table” analogous to String Coffee Table.
    This would report on conferences and research gossip. Someone
    in Loop cosmology at the postdoc level, maybe Parampreet Singh.

    this is just a pipedream. not a real idea. but it would be nice to have
    some regular source of news and views from young researchers in QG analogous to string coffeetable.

    criticism of string, which Clifford seems to fear would dominate such a blog, would I think hardly be an issue. these people tend in my experience to be too busy with their own interests to bother criticising the string-that-be establishment. have to run, so must leave this
    post in rough shape

  5. cvj says:

    Simplex, Do read my post again. You seem to have misunderstood it. Perhaps it was because you were in a hurry. That happens. Let me help you by repeating: I am advocating blogging postitively about alternative approaches and cautioning against blogs set up purely to be in opposition to a specific approach, which is rather different. You use the word “fear”. Yes, I fear pointless and wasteful negativity taking over from positive and constructive discussion. I do not fear constructive criticism of string theory. I hope that your positive suggestions are implemented in some shape or form, since I for one would like to learn more about alternative approaches, for my own education about what other people are doing, if nothing else. This is an important quest we’re all on; no good idea -in any field- should be wasted.



  6. Peter says:

    About Garrett’s suggestion:

    First of all, in any case I can’t do this. For one thing, while I think it’s appropriate for my department to be hosting my current weblog, it probably wouldn’t be an appropriate place to host a group weblog like Cosmic Variance. More importantly, the time and energy to coordinate the activities of several very different people would be significant. Especially if they’re chosen for not wanting to follow the most popular path in particle theory, they’re likely to have strong opinions about how things should be done, and dealing with this would strain my rather limited political skills.

    What I ‘d really like to see is just a lot more good people setting up their own weblogs, perhaps cooperating to the extent of coordinating with a site that aggregates content from many different places. Alejandro Rivero’s is one version of this kind of thing.

    As for Clifford’s comment: I didn’t interpret what Garrett had in mind as an “anti-string theory” site, but rather as a place for people interested in alternatives to string theory to be able to have a forum to exchange ideas. There’s a strong feeling of frustration among the people I talk to who aren’t happy with string theory about the lack of an active intellectual community that they can participate in. The only one that really seems to exist is the LQG community, to the extent that Simplex just assumed that this is what an alternatives to string theory weblog would be about.

    Anyone should soon realize if they follow my postings on this site that I’m fundamentally a particle theorist, not a relativist, and don’t see quantum gravity as the most fruitful thing to think about. There’s not a shred of experimental evidence about quantum gravity, and little in the way of prospects for getting any during my lifetime. If you believe the most extravagant claims discussed at the Toronto panel, every QFT is dual to a consistent quantum gravity theory, so there is no lack of those. The real problem is not finding a quantum gravity, but finding a quantum gravity that simultaneously explains what is going on in the standard model. String theory became so popular because it promised a solution to this problem, a promise which has not been fulfilled.

    I think Garrett and others share in varying degrees my point of view that what is needed is a much deeper understanding of the mathematical structure embodied in the standard model, and a frustration at how difficult it is to sometimes even get other theorists to acknowledge that this is a reasonable thing to be thinking about. Over the past twenty years the reaction I keep getting from many string theorists is that anyone who is still thinking about QFT itself is probably just not smart enough to be working on string theory.

    Simplex, whoever he or she is (and by the way, I’m really tired of having my professional qualifications challenged by people who cowardly hide behind the cloak of anonymity) contrasts me to “people who are ACTIVELY PURSUING ALTERNATIVES on a professional basis” who he or she identifies with “postdocs or young faculty who are involved with the main nonstring lines of QG research”. Well, believe it or not, there are people out there, actively pursuing alternatives on a professional basis, who aren’t involved with the main nonstring lines of QG research. It’s a difficult path to follow, largely because there is no active intellectual community to participate in, and much of the physics community, like Simplex, seems to believe that something that doesn’t fit into string theory or LQG, like hep-th/0206135, doesn’t count as “real” research.

    So I think I understand what Garrett would like to see, and I would too, but the difficulties are very large. I’ve devoted so much time to making the case that string theory has failed as a way of understanding the standard model because I believe that the physics community is not likely to be willing to take an interest in speculative alternative approaches as long as the perception remains that “string theory is our best hope for a unified theory”. Why should anyone waste their time on anything but the best hope?

  7. simplex says:

    sorry Peter, my mistake
    didnt for a moment intend to challenge your prof. qualifications!
    I see how my careless assumption that your research is
    not on alternatives to string may have seemed insulting

  8. Peter says:

    My last comment crossed Clifford’s, and his reminded me of some other points I wanted to make, especially since I think I’m very much in agreement with him. I don’t think that setting up a purely “anti-string theory” blog is a good idea, and despite appearances, that’s not what I intend this one to be. As I periodically remind people, “Not Even Wrong” refers to speculative theories that are not well-defined enough to be testable, and I’m all in favor of work on such theories. Such work is the necessary starting point for getting to a theory that is testable. My objection to string theory is not to its speculative or mathematical nature (I’m in favor of those), but to the way in which the field has both immunized itself against any honest evaluation of whether it is getting anywhere or not, and simultaneously made it difficult for other speculative research programs to get any attention.

    I try to cover here newsworthy things that seem important to me. These include any news about experimental high energy physics, both any current experimental results and prospects for possible ones in the relatively near future. They also include a lot of material about mathematics, concentrating on those aspects of mathematics that seem likely to me to ultimately have something to do with particle theory. I’m frustrated that there’s not more of this kind of thing to write about, unfortunately the area of overlap between mathematics and particle theory that seems most promising to me has had very few people working in it in recent years.

    Probably about half the material here is about string theory, and much of that is negative. In my last comment I explained why it seems important to me to try and make the case to the physics community that string theory is not the “best hope” around for unification. It’s also true that this is a form of journalism and the string theory story is one in which a lot of amazing things are happening. A novelist couldn’t make up things like Lenny Susskind and the “high-school food fight” he sees himself engaged in. It’s a fascinating story, I can’t wait to see what will happen next, and years from now I think people will look back on this as a truly remarkably weird era in the history of physics.

    Well, as an example of the kind of positive thing I think people should be paying attention to, a few days ago I reported that Witten would be speaking today at Smith Point Beach about “Gauge Theory and the Geometric Langlands Program”. I should stop this and go listen to his talk, the audio of which has just appeared on the net. Also, should go and check to see if there’s anything worth reading on the arXiv, and, yes, finish doing my laundry.

    Simplex, just saw your latest comment. Sorry I misinterpreted your earlier one, my error for being overly sensitive about some things.

  9. garrett says:

    I’ve been out all day, and in coming back I see the suggestion I made has been digested, thought about, and in the end properly interpreted, which — just being a random commenter here — I’m very pleased to see. To elaborate a bit, and since Peter has a good idea of what I was suggesting but it isn’t super clear, I want to give the background I had in my head when I proposed it.

    I have a group of friends I talk with regularly who are a-religious, and we have a mailing list for random discussions. Sometimes the discussions that pop up are pointing out, making fun of, and/or just shaking our communal head at crazy religious stuff happening in our world. This provides a bond for the group, and some dark humor value. But the group overall is very upbeat and constructive. And more often discussions arise about new technological or interesting scientific developments. It’s a good time. But the community wouldn’t hold together without its common, and uncommonly held, bond of appreciation for science and complete lack of tolerance for religion in its worst forms.

    This is what I had in mind when envisioning an a-string-istic group weblog. Peter’s posts exactly capture the dark humor inherent in the dominance of string theory and it’s inability to explain our world. But there needs to be a constructive side too. And there are many people, including but not restricted to people doing LQG, CDT, etc., working on alternatives. The sane ones hold two things as sacred: quantum field theory and general relativity. These, I think, include many of the people reading this weblog. And, looking among them, I see a lot of people holding threads that, optimistically, may be hanging off the same piece of cloth. Peter’s manifesto suggests everything has to be about connections. Tony Smith sees Clifford algebra behind the standard model. Matti Pitkanen sees everything as related to CP2. I’ve seen how fermions can arise naturally as the BRST ghosts conjugate to gauge degrees of freedom in a certain formulation of GR. And Gordon, who I’ve known since we were undergrads, has a different angle on QFT. And all of these people (and I’m sure some reading this whom I’ve left out), working completely independently, have things that overlap significantly in their models.

    And Peter, perhaps the strongest critic of string theory, does post constructive things in this weblog, so I thought he would best get the idea of what I’m suggesting. But, I’m afraid Peter is right and it would be intractable to moderate a group weblog involving such vigorously independent folk. It would be like trying to herd cats. The postings would more than likely digress to each person espousing their work and not looking into the work of the others. The same spark that drives these people to strike out on their own is the one that keeps them from playing well with others. So I can see it would probably just be ugly to try to gather a group of fierce individualists.

    We can only hope that someone out there on their own working on crazy ideas will come up with ideas crazy enough to be true.

  10. D R Lunsford says:

    Somewhere in the above mass Smolin wrote:

    “..yada yada extending quantum mechanics to cosmology yada yada…”

    Pray tell, how is one going to prepare the entire Universe for observation? By who? In what lab?

    Talk like this is just meaningless. Word salad.


  11. cvj says:

    Don’t abandon the idea entirely. Let it be a bit incoherent, that’s ok. I think it would be great to have a place where someone (one or a few people) simply make posts on what is going on in the “alternative approaches” world, describing for the benefit of everyone what the idea is behind a given peice of work that someone has published, how it fits into the scheme of things, what it is trying to do, and whether there are connections with anything else. Nobody has to moderate it per se – let the cats do what they want in the comments; the posts will speak for themselves – it would still be of value to the entire community to have a place where people can know that alternative ideas are being showcased and discussed. It would relieve some of the frustration that people have because they percieve that string theory is running a closed shop – there’d be a place you can “gather” and have your own chatter, on your own terms – and it would be good for the stirng theorists too, since there’d be less of that random posting of alternative theories right in the middle of a discussion of something else. No matter the value of that alternative, it is hardly ever useful to do that – it just derails any discussion because it would take too long to digest the new material…but people do it. Now they can place a link to a discussion of it on another blog. Everybody wins! Garrett – just do it! It would be a valuable service if you keep high the scientific integrity and the quality of discussion. Start out doing it yourself and simply invite guests to blog from the blog platform every now and again. Some of them might then stay on if the fit is right.


  12. Quantoken says:

    I disagree with the notion that Peter is the strongest anti-string critics. Actually I think it’s exactly the opposite. He seem to be rather strange in his stands. The strongest argument he ever presented against super string theory research, is that 20 years passed and it doesn’t seem to be able to predict anything yet. That argument is rather weak and it hardly even convince himself that SST is wrong, and is easily refuted by noting that QG itself is a difficult topic and 20 year may just not be enough to make progress. There is indication that Peter himself believed as much as most SST researchers that there is possibility one day STT MIGHT come out all right and all figured out. And Peter nod his head in agreement and sing the praise song with the mob when SSTers point out that there’s too much math beauty found in SST that simply could not be wrong. Clearly Peter believes that the argument of math beauty is so strong that he is persuaded by it, too. At the end of day Peter is really not anti-string, but merely complaining the lack of progress, which all but make him a member of the SST camp.

    It is rather strange that Peter paid a tremendous interest in every single act of the top SST researchers, and every single word they utter, down to very details. For example he desperately wanted to know how 8 of the SST guys voted in a behind door settings (which to me sounds like a silly childish religious ritual.) Another example is he paid extremely close attentions to every thing Witten ever says or does.

    If one truely believes that SST is the wrong approach that leads no where, then Witten etc are simply wasting their time and they are destined to go no where, and there is no chance they ever discover anything physically significant, then who would one pay so much close attention to Witten et al.? To the point that Peter almost looks like a dissiple of Witten as much as Tom Cruise is a dissiple of Ron Hubbard. Why?

  13. Tony Smith says:

    Garrett says:
    “… an a-string-istic group weblog … would be intractable to moderate … It would be like trying to herd cats. The postings would more than likely digress to each person espousing their work and not looking into the work of the others. The same spark that drives these people to strike out on their own is the one that keeps them from playing well with others. So I can see it would probably just be ugly to try to gather a group of fierce individualists. …”.

    cvj says:
    “… Nobody has to moderate it per se – let the cats do what they want in the comments; the posts will speak for themselves – it would still be of value to the entire community to have a place where people can know that alternative ideas are being showcased and discussed. It would relieve some of the frustration that people have because they percieve that string theory is running a closed shop … and it would be good for the stirng theorists too, since there’d be less of that random posting of alternative theories right in the middle of a discussion of something else. … Everybody wins! …”.

    As one of Garrett’s cats, my opinions may be relevant, so here they are:

    Garrett is correct that it is likely that the cats would “digress to each person espousing their own work”. For example, although Matti (another cat) and I agree in using M4xCP2 as a fundamental spacetime geometry, Matti wants to vary hbar and I want to fix hbar as a constant. There is no way that Matti and I can devise a single model that does both at once, so on that point at least Matti and I could never arrive at a consensus model that makes both of us happy.

    cvj says such a blog would “relieve some of the frustration” that I have because I do in fact “percieve that string theory is running a closed shop”, which closed shop even extends to me being blacklisted from posting on arXiv.
    I disagree, because even if such a blog resulted in the production of a consensus alternative model that all the bloggers (and the blog moderators) considered to be realistic, it could not be posted on arXiv if it involved
    elements due to blacklisted people (including, but not limited to, Matti and me), and my frustration level might even be increased.

    cvj also says “… it would be good for the stirng theorists too, since there’d be less of that random posting of alternative theories …”. I do not disagree with cvj that conventional superstring theorists would be happier if alternative theories were hidden from their sight in a ghetto blog that they felt free to totally ignore.

    In other words, cvj’s remark “Everybody wins!” really means only that “Conventional Superstring Theorists win!”.

    In my opinion, the main real problem is that there is no mechanism in the physics establishment to evaluate alternative theories, such as, for example, by giving alternative theorists opportunities to defend their work before an establishment forum that would actually consider, criticize, and evaluate the alternative theories.
    Given the current political structure of the USA physics community, I feel that it is unlikely that any such forum will ever be set up.

    As I have said before, current conventional superstring theory has much in common with Chew’s bootstrap theory, which was so socially powerful that even Gell-Mann was intimidated into apologizing that his quarks were not real, just mathematical abstractions that might be useful.
    Chew’s bootstrap theory remained powerful until the acceptance of the Standard Model, which emerged from Harvard and Princeton with the help of Kobayashi, Maskawa, and ‘t Hooft.
    Until an alternative to conventional superstring theory is accepted by a similarly powerful group of institutions and individuals, it is clear to me that inertia will keep conventional superstring theory in power.
    A ghetto blog such as suggested by cvj is highly unlikely to get any alternative accepted by such institutions and individuals, so I agree with Garrett that it is an impractical idea given the culture of the current physics community.

    Tony Smith

  14. Alejandro Rivero says:

    drl, your point is additional motivation to rethinking QM in the context of gravity, is not?

  15. Chris W. says:


    There can be advantages to being in a ghetto, if you have intelligent company, and time to think about, develop, and discuss your ideas. Maybe this assertion reflects a prejudice of mine, which is that the problem (quantum gravity/unification) is suffering from a surfeit of formalism combined with a shortage of truly significant insights, lucidly expressed. In the end such insights may also be precisely what highest on Peter’s agenda — a deeper understanding of QFT and gauge theory. Indeed, how could they not be?

    (PS: I wonder if Perimeter Institute would be willing to host such a group blog?)

  16. rof says:

    DRL said:

    Pray tell, how is one going to prepare the entire Universe for observation? By who? In what lab?

    Talk like this is just meaningless. Word salad.

    Alejandro said:

    drl, your point is additional motivation to rethinking QM in the context of gravity, is not?

    DRL is more accurate here, because the distinction needs to be made between gravity and cosmology. I can drop a book in a lab and see it fall and so it is necessary to incorporate gravity if I want to predict the results of experiments.

    On the other hand, the quantum formalism, which essentially tells us to represent the state of the system under investigation as a formal sum of measurement results (hence a|up> + b|down> etc), is inapplicable to the universe as a whole, considered as it is in itself, rather than as a set of measurement results obtained by an observer.

    Something must yield – either the notion of considering the universe as a whole system seen from the point of view of no observer, or quantum mechanics. Witten, ‘t Hooft, Penrose and so on seem to be suggesting that it is quantum mechanics that will yield. No doubt they have carefully considered the alternative and rejected it for good reasons which they consider too obvious to need mentioning.

  17. simplex says:

    getting back to the toronto panel video, it occurs to me to ask what happened after each time Lee Smolin spoke. I will go back and check. If there’s a pattern, it might be interesting to notice as a way of gauging the receptiveness to ideas from outside, on the part of string theorists in a group. Maybe there’s something quite different to learn from the reaction (who can say in advance?).

    besides the exchange about quantum computing and foundations (connections between those two lines of research) there were two main instances I can remember.

    One was when Smolin urged string researchers to put more effort into background independent reformulation–giving arguments why such a reformulation was urgent, possible, and could lead to testable predictions. this came quite early in the open discussion — around 1:09 to 1:12 (I checked–it was 1:08:45 to 1:12:25 by my counter.)

    The other occasion I recall was, I think, after Jan de Boer raised the issue of falsifiability. this was about time 1:44. (I checked–it was 1:43:45) Replying to de Boer, Smolin spoke about predictions of modified Lorentz invariance coming out of LQG and possibly other non-string QG. And he mentioned two tests: one (AUGER) already collecting data and one (GLAST, Smolin didnt name it) scheduled for orbit in a year or so.

    This is all I remember, may have to correct or add some significant detail after another hearing.

  18. Chris W. says:

    Another reminder, regarding the search for testable QG consequences: There is some recent work indicating that violations of Lorentz invariance associated with quantum gravity may be generically more acute than previously assumed, unless some sort of fine tuning — or symmetry — suppresses them. A paper following up on this work examines a well known supersymmetric model (Wess-Zumino) and finds evidence that supersymmetry can provide the desired suppression.

    See hep-ph/0502106 and its cited preprints.

  19. Alejandro Rivero says:

    About that group blog… it is in principle possible to rent cheap web space with php scripting included, for instance my is lodged in, a italian company, just to avoid local institution problems of the sort Woit insinuated above. Now, is there some interest on having such blog backed by a strong entity, as Chris seems to be suggesting?

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