Some Early Criticism of String Theory

From the “First Superstring Revolution” on, there have always been skeptics, even though they often were not very vocal. Perhaps the most well-known piece of such criticism was Paul Ginsparg and Sheldon Glashow’s Desperately Seeking Superstrings, which appeared in the May 1986 issue of Physics Today. I recently became aware of some other similarly critical articles by Noboru Nakanishi, and copies of them have been made available to me. They are:

Comments on the Superstring Syndrome (also from May 1986)

“Superstring Theory” Syndrome (published in the popular magazine “Parity”, September 1986)

Can the superstring theory become physics? (January 1993)

This last paper claims that “the bubble of superstring theory has … bursted”, which, in 1993, was rather premature.

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77 Responses to Some Early Criticism of String Theory

  1. D R Lunsford says:

    Nakanishi makes an extraordinarily accurate point!

    “I believe that any correct quantum theory should be able to be formulated in the Heisenberg picture. As long as one does not give up the idea of adding the interaction part to the free-field theory, one will never attain the fundamental theory.”

    There is so much truth in these two sentences!

    -drl

  2. G. Borner, in his book “The Early Universe – Facts and Fiction” (1988), also cites Ginsparg and Glashow on page 223:

    Let us hope that from its phase of floating around in the imagination, superstring theory will be able to find some connection with reality. Let us wait and see whether it succeeds or whether it ends up as the kind of thing that Pauli would have characterized as being “not even wrong”.

    Christine

  3. Conrad says:

    Speaking as an interested layman with a degree in philosophy, I have never understood how it came to be that superstring theory became so entrenched as THE theory. I always knew that the theory made no testable predictions. I always suspected it to be something like Alfred North Whitehead’s theory of gravity(anyone out there there ever hear of this- but it was once a big deal)- an elegant theory written by a brilliant mathematician that ultimately goes no where.

  4. Chris Oakley says:

    DRL – agreed. Also known as “Haag’s theorem”. In between progamming bouts for the client, this is what I am looking at now.

  5. Kea says:

    This last paper claims that “the bubble of superstring theory has … bursted”, which, in 1993, was rather premature.

    Does that mean you think it has burst now?

  6. Peter Woit says:

    Kea,

    I don’t know. There’s certainly a lot of noise, but is it the noise of a bubble bursting or something else? Time will tell…

  7. hack says:

    There’s a saying that goes something like “Bubbles always last longer than you think is possible, even after taking into acount for the fact that they always last longer than you think is possible”.

  8. ralf says:

    Couldn’t one say that superstring theory has never been a part of physics as a (once) serious science, but has rather always been a phenomenon of the sociology of physics and the politics of academia and science funding? The exact moment of the bursting of its “bubble” may have been/be (hopefully) different for different people. For me there never was a “bubble” in the first place.
    I think nobody who even considers the mere possibility that the entire physical reality is a consequence of the super-Virasoro algebra should be considered a serious physicist.

  9. King Ray says:

    String theory is a compendium of failed ideas… Kaluza-Klein, string theory of hadrons, supersymmetry, supergravity, etc. Why would you expect to get the correct theory by combining so many failed theories? I never found any of those ideas aesthetically pleasing anyway, and all mixed together they are even less so.

  10. Thomas Love says:

    Are we now replacing string theory with bubble theory?

  11. Kea says:

    Are we now replacing string theory with bubble theory?

    Exactly! By showing that string theory is merely a moduli space technique for doing rigorous QFT one removes the necessity of landscapes, higher dimensions, KK and all that.

  12. JC says:

    I vaguely remember the early 1990’s being a slump for string theory. Besides the people who were working on mirror symmetry stuff, it looked like a number of the hardcore string people were banging their heads on the heterotic string (attempting phenomenology) without much success.

    At the time I wondered whether the string bubble had actually bursted. I never thought that string people would become interested in 11d supergravity or supermembrane theory again. (In the mid-late 1980’s, some string folks thought supergravity was a dead end).

  13. D R Lunsford says:

    King Ray – agreed! It always struck me as curious that something that appeared so physically ad-hoc could generate so much interest. My conclusion was that the interest was not coming primarily from physicists, rather mathematicians. I’ve always thought that the popularity of string theory may have derived simply from creating a large number of mathematicians during the Cold War, in a world short on things remaining to be proved – and so they fell on string theory because it was a fertile playground for mathematical speculation.

    -drl

  14. dark-matter says:

    Amazing predictions from Ginsparg/Glashow and Nakanishi, 20 years ago.

    Conrad:
    For a philosophical essay see: http://www.arxiv.org/abs/physics/0610168

    ST will proceed by sheer momentum and the power of denial. Maybe there are Miracles. LQG, having successfully dealt with quantization of GR (see http://www.arxiv.org/abs/hep-th/0605052) is now engaged in developing couplings to matter fields and taking a crack at unification. It may or may not produce something in the next few years. The best guide to developing a replacement for ST is the LHC, gravitational waves experiments, and satellites/telescopes. In another words, let the experimentalists take the baton and bring in some much-needed facts.

  15. arnold says:

    The article by Glashow and Ginsparg is really good.
    Thanks Peter.

    I always wondered how a theory which makes no conceptual breakthrough (it is just a naive hypothesis that matter is made out of strings) can have anything to say about the world 16 orders of magnitude smaller than what we know!

    If you think about it, special relativity was a conceptual earthquake, as general relativity, and quantum mechanics.

    String theory is just some naive generalization of Feynman diagrams to extended objects. And in order to even hope to make sense it requires so many adjustments (supersymmetry, more dimensions, some funny
    compactifications to cure problems that were created by the theory itself,…) that it becomes almost ridiculous.

  16. King Ray says:

    DRL,

    Someone once told me to beware of people that mathematicians think of as physicists and physicists think of as mathematicians.

    I think also a lot of people have invested a lot of their careers in these failed ideas and want to see them survive in some way, so they have jumped on the ST bandwagon.

    The string theorists just lack the nose for beauty and truth that Einstein had, that tells one if one is on the right track or not. Going from the SM to ST is like trying to deduce the shape of the whole iceberg from the part above water; it is extrapolation, and that rarely works well. Maxwell only added one term to one equation when he unified E&M, he didn’t add hundreds of more forces. Likewise with EW theory.

  17. The Anti-Lubos says:

    Conrad: Speaking as an interested layman with a degree in philosophy, I have never understood how it came to be that superstring theory became so entrenched as THE theory.

    Read Peter’s book. Seriously!

  18. Tony Smith says:

    Noburu Nakanishi is professor emeritus at Kyoto University and co-author (with Izumi Ojima) of a well-known book, “Covariant Operator Formalism of Gauge Theories and Quantum Gravity” {World Scientific, 1990).

    His most recent paper is hep-th/0610090 “Spacetime in the Ultimate Theory” in which he is critical of both non-commutative geometry and superstring physics models, saying:

    “… Recently, the quantized spacetime has been revived owing to the fashion of the non-commutative geometry. But the quantized spacetime seems to be investigated in favor of the mathematical interest rather than the physical requirement. … Hence the calculations concerning it often become no more than mathematical exercises. Of course, one may claim that the quantized spacetime is an approximation of string theory, but such an assertion implies that the quantized-spacetime theory itself is not a candidate of the ultimate theory.

    Some of the superstring people believe that it is fruitless to consider any other theory because the superstring theory is the unique candidate of the ultimate theory. I believe, however, that such an assertion is too much prejudiced, because there are several fundamental difficulties in the superstring theory and nothing of them have yet been resolved … there are absolutely neither theoretical nor experimental evidences which justify the huge extension of the theoretical framework done in the superstring theory.

    utterly no superpartner-like particles predicted by SUSY are discovered. It is quite unnatural
    to assume that all superpartners have a mass so large that no present-day accelerators can
    produce them without exception … If NATURE does not adopt SUSY, supergravity and superstring must be abandoned, and many people researching them will become greatly embarrassed. …”.

    His paper is NOT merely criticism of non-commutative geometry and superstring models,
    since
    in it he propose a concrete model for spacetime (although not, in that paper, extended to describe all the particles and fields of the Standard Model). You should read the paper hep-th/0610090 and the book mentioned above for details, but here are a few excerpts that might give an indication of his ideas:

    “… The quantum theory of gravity thus constructed turns out to have a 16-dimensional supersymmetry … based on the “16-dimensional supercoordinates” x^mu, b_nu , c^r, c’_p , where c^r and c’_p denote the Faddeev-Popov ghost and anti-ghost, respectively

    More precisely, its superalgebra is the (8+8)-dimensional inhomogeneous orthosymplectic superalgebra consisting of 144 generators. Of course, the affine algebra is its subalgebra

    In the framework of indefinite-metric quantum field theory … many unbroken symmetries are available without predicting the existence of extra physical particles, so that one can construct the action having a large (super)symmetry which may unify the spacetime symmetry and internal symmetries without contradicting the no-go theorem for the extension of the Poincare symmetry …

    both the physical spacetime and the Lorentz symmetry of particle physics are the
    secondary concepts appearing as a consequence of the spontaneous breakdown of symmetries … the Nambu-Goldstone boson corresponding to the symmetric-part generators of general linear transformations is nothing but the graviton. This fact guarantees the exact masslessness of the graviton. …”.

    The final sentence of his abstract in hep-th/0610090

    “Any criticism on my opinion is welcome.”

    is a welcome contrast to some of the attitudes seen in the USA high energy theoretical physics community.

    Tony Smith
    http://www.valdostamuseum.org/hamsmith/

  19. Jeff says:

    Peter,

    Nice links. 🙂

    String theory – for all its grandeur – is still a work in progress, even though you validly claim that 30+ years is a long time for a theory to be in development. Ofcourse, maybe the unspoken understanding may be that so long as Edward Witten thinks strings are a viable approach to QG and unification, the program will continue on unhindered.

    But my post is not on strings per se; I wanted your view on what ‘twistor theory’ has to offer for QG (or even unification). Roger Penrose writes in his latest work (rather convincingly) that twistor theory has deep relations to physics that has not been fully explored as yet (due in large measure to string theory’s dominance of hep-th research). Do you think twistor theory might have good potential in the future?

    Regards,
    Jeff

  20. 1995 says:

    Things started going wrong in 1995.

    Around 1985, string theory seemed to be what we need: a theory of quantum gravity able of predicting its low energy QFT limit. Strings correctly become the mainstream.

    But in 1995 people working on string physics had achieved nothing, while people working on string theory gave interesting results, showing that the theory was more rich than initially envisaged. This complication was a bad news, but many people were happy. Indeed, at this point the community was large enough to allow a self-referential study of the mathematical aspects of a theory that was loosing the initial physical motivation that turned it into mainstream.

    String theorists now understood that they must start delivering truly good physics. Either this happens within a few years, or will not happen.

  21. D R Lunsford says:

    King Ray – Smolin says that ST is probably a consequence of the Feynman/Dyson “hard-nosed” approach to physics, where calculational virtuosity is the main skill, and contemplation of fundamental issues is secondary. Naturally, physical mathematicians are going to have a bigger role in such an enterprise than mathematical physicists. And I agree on your comments RE beauty – that is, beauty is a good guide, but you have to be able to see it first!

    -drl

  22. Bert Schroer says:

    D R Lunsford
    I don’t think it is quite that simple because for a long time (up to the early 80s) ST did not have a mathematical attraction. It was Witten who showed that it can be used as a vehicle which carries metaphoric physical ideas into interesting mathematical conjectures.
    Physically it had no historical connection; its birth was a shot from the hip, a strange combination of the most crude phenomenology (of saturating the intermediate state completeness property by an infinite tower of intermediate one-particle states) with Beta-function engineering. It unfortunately happened at a time when the success hubris from the standard model (see Phil Anderson’s criticism) was in ascend and the conceptual control of of speculative proposals out of the blue were on the decrease. Only in this way one can understand that the result of a prescription was called S-matrix without ever checking whether it even satisfies the most crude properties (e.g. multi-particle clustering) without which that physical name is completely undeserved.
    Feynman’s and Schwinger’s computational power was conceptually controlled and not rampart.

  23. Alejandro Rivero says:

    Amusing coincidence that the criticism of Ginsparg/Glashow were published in the “Reference Frame”. I guess that this article substantiated some of the gossip about why hep@xxx was divided in hep-th and hep-ph (yep, and hep-lat, but that can be more obvious). And actually it is the first physics/… paper, is it?

  24. anonymous says:

    a posteriori one should now admit that crackpot Noboru, crackpot Paul and crackpot Sheldon correctly guessed many of the present problems. Still, I think that their criticism was too early and that strings had been a very good attempt, altough unfortunately the criticism of crackpot Peter and crackpot Lee might be close to the end of the story.

  25. D R Lunsford says:

    anonymous – I don’t see how you can maintain this position in the light of Nakashini’s extremely pointed criticisms. His essay is wonderfully to the point and succinct and hits the main issues of principle, without even going much into the technical details that Peter stresses. The paper linked by Tony Smith is also very much to the point and filled with physical insight. His insistence on having a Heisenberg representation for any final quantum theory is the best point in physics I’ve seen made in public for a long time. It should be pointed out that quantum theory was born this way. I think students should get a history course taught out of “Sources of Quantum Mechanics” by van der Waerden.

    -drl

  26. Chris Oakley says:

    Anonymous,

    I am surprised that you failed to mention that crackpot Popper, who required that physics should be based on mathematical models that are open to being proved wrong by experiment.

  27. Chris Oakley says:

    Oh, and another thing, in case non-native English speakers are getting confused: “burst” is the same in the past tense, and is therefore not a regular verb.

  28. D R Lunsford says:

    Chris – it is too bad the crackpot Dirac died in the same year as the Green-Schwarz coup. I wonder what lame comments he would have made?

    -r

  29. Eamon says:

    I don’t think that the bubble, if you can indeed call it that, will burst. I mean – how would such a thing play out? Too much reputation, energy, and money has gone into this.

    What these older articles prove is that the shortcomings of string theory were already observed and noted long ago. They were ignored then, and will probably be ignored now. It even took off without a good connection to experiment. Why would that hurt it now?

  30. Chris Oakley says:

    Here is an exercise for the reader. Subtitute one the following for “the bubble” in Eamon’s first sentence:

    (i) Enron
    (ii) LTCM
    (iii) Ptolemy’s epicycles
    (iv) Alchemy
    (v) Communism
    (vi) Star Wars SDI
    (v) The Hindenberg
    (vi) Sony Betamax

  31. Chris Oakley says:

    … and finally

    (xlci) my ability to count in roman numerals

  32. Bert Schroer says:

    Eamon
    I agree with your pessimistic assessment.
    Unless the most charismatic updater of ST returns to particle physics, i.e. to that what he was doing before he met Atiyah, and hence through this very act renounces ST (which we all agree is not particle physics) there will be no change. However I doubt very much that ST will survive the passing of its protagonists and Nobel supporters.
    As a result of its predictive vagueness it will most probably survive LHC, especially if new data resist satisfactory theoretical interpretation for a longer period of time.
    According to Phil Anderson one should expect that the duration of ST is direct proportional to the hubris in the aftermath of the unmerited success of the SM, but it is difficult to quantify hubris apart from registering (looking at its aggressive supporters) that it is still going pretty strong.

  33. Ari Heikkinen says:

    Yes, exactly, there’s always been critics of string theory since its very beginning, yet many researchers have found it interesting enough to continue working on it over the years.

    As far as I can recall, initially string theorists were called crackpots by physicists, not vice versa.

    I still don’t quite understand what’s the big deal about the critism now. There’s, for instance, Glashow’s critism of string theory even in popular books about string theory like Greene’s that’s been there long before Lee or Peter wrote their books.

    My point is, the critism is nothing new.

  34. Bert Schroer says:

    Can anybody explain why the title “crackpot” is so popular around Harvard? In an earlier reaction of Peter to anonymous he suggested that there may be something in the water around Harvard.

  35. egbert says:

    It’s not just Harvard. It seems to have become a fundamental part of the string culture that, since nobody really understands what’s going on, reputation is everything. When a string theorist meets some physicist, he rushes to judge that person’s intelligence, and if that person says things that coincide with what the string theorist has heard from people he respects, then the person is intelligent and if he says the opposite he’s a crackpot.

    In the KITP video where the journalist in residence talks about Lee’s and Peter’s books, somebody in the audience proposes “taking a vote” about whether Lee Smolin is a crackpot. The vote didn’t go ahead, perhaps because they knew they were being recorded and broadcast on the internet. But from the general hostility the audience was showing (even though they hadn’t read the books), I think there can be little doubt about what the result of a vote would have been. The grad students learning string theory at UCSB will develop their opinions of who is an actual scientist and who is just some crazy crackpot in this environment.

    Susskind does something similar in his review of the books. He tells stories about shipbuilders and explorers but in the end all he does is attack reputations.

  36. Bert Schroer says:

    Ari Heikkinen
    I think there is a big difference if some individuals were called crackpots by the particle physics mainstream (I don’t recall that this expression was in use in those days, probably the majority used to think that this was “crazy stuff” or something similar) or if string theorists think that everybody else is a crackpot. The last situation reminds one of a group of ghost drivers who drive down the highway in the wrong direction and shout at everybody who is driving the right way because they are not yet aware of their mistake.
    And by the way, this is one of the few instances where the majority was right.

  37. Energex42 says:

    In my mind, this round of String Theory criticism is more credible. LQG is making rapid progress, and creating a set of predictions. String Theory still have nothing to say about predictions.

    Ironically, String Theory may be saved one day because LQG manages to see strings in an effective field theory.

  38. Bert Schroer says:

    No, please, it is not very effective.

  39. steve says:

    As an interested outsider (not a natural scientist), it has fascinated me how strong the social policing within physics (and to an extent astronomy and cosmology) is about crackpots. The structural reason for this is obvious–there are a lot of people who don’t know what they are talking about who want to participate in the conversation and/or fantasize themselves as the new Galileo. In order for the conservation to be useful, the idiotic stuff has to be filtered out.

    But the policing of crackpotism seems to me to go well beyond that. Even well-credentialed people who go off the reservation get cast into the outer darkness. It looks like most fields of science have foundational weak spots that everyone agrees to leave alone while working on superstrucural puzzles (if you’ll pardon the metaphor). Everyone in the field has some existential worry that those weak spots will fail and bring down the whole structure, and they don’t like people reminding them and pushing these issues to the foreground. So they declare anyone who worries about these matters to be a crackpot as a way of eliminating the cause of their anxiety. And by “shunning” these critics (in much the same way closed religious communities like some Mennonite sects do) they can exorcise the threat to communal well-being. Out of sight, out of mind. The shunned are rendered powerless to influence anything during their lifetimes.

    Objectively, the shunners may well be correct in their scientific beliefs more often than not. But given a) the importance of the results if the “heretics” are in fact correct, b) the stimulus to mainstream theory created by the heretics, and c) the self-censorship that must cripple creativity when people want to avoid being shunned, I think a bit more tolerance for others’ crazy ideas would be good right now. Personally, if the core theory in my field had problems like getting the vacuum energy wrong by 120 orders of magnitude, I’d be open to creative suggestions, even if they seemed a little bit cracked.

  40. TheGraduate says:

    steve:

    I like what you said. Of course, what you say is just a general scenario that may or may not apply in individual circumstances. But I think it is a scenario that does seem to play out often.

    However, I am surprised that so few physicists are willing say, “Yes there is no absolute proof of what I believe but I’m going to work on it anyway and since I believe it’s the best idea, I am going to tell everybody else to work on it too.”

    They seem to prefer quarreling over the subjective value of the inconclusive evidence.

  41. Chris W. says:

    [My apologies; it looks like I neglected to properly close an <a> element in the previous comment. Let’s try again…]

    Steve,
    I think one can interpret the tendency to label people crackpots in economic terms, especially these days. It costs something to sympathetically and carefully consider someone else’s ideas, including time taken away from pursuing whatever research agenda one happens to be interested in. There is a strong incentive to latch onto reasons for quickly dismissing an idea, if only to save time for investigating other options, any of which may demand considerable effort. Like most successful and ambitious professionals, scientists hate to waste time, and look askance at (erstwhile?) colleagues who appear to be investing their time carelessly.
    In contrast, Michael Nielsen quotes Freeman Dyson, speaking of J. Robert Oppenheimer:

    … we can see the nature of the flaw which made his life ultimately tragic. His flaw was restlessness, an inborn inability to be idle. Intervals of idleness are probably essential to creative work on the highest level. Shakespeare, we are told, was habitually idle between plays. Oppenheimer was hardly ever idle.

    In this context, one should recall Aaron Bergman’s repeated references to (and laments on) the relentless pressure to produce substantive research output, especially for younger scientists, and the general antipathy that most working scientists have to philosophical discussion, which they regard as mostly fruitless, if not altogether sterile and pedantic.
    What I think many people are looking for at this stage in quantum gravity is a galvinizing idea—something that is both original and clearly relevant, ie, appears to be getting at the heart of the matter. (They also fear the paralyzing effect of knowing too much, ie, tending to immediately think of convincing reasons to suppose that any new idea couldn’t possibly work.) Until such an idea appears there will be a lot of simmering frustration and some short tempers.

  42. Garbage says:

    Peter,

    This is why this blog misses the oportunity to be a good place to discuss physics. You have an interesting post on finiteness of N=8 SUGRA, which if true would certainly produce a (though unrealistic) more *traditional* finite theory of gravity, that doesnt count more than 8 comments. In the other hand, this one on early critics of ST clicks 40 in a few days. It seems to me like you keep repeating yourself over and over, and even though I agree ST has grown perhaps way too far it should have ever been, and also particle physics needs to hit a *refresh*, I dont see the point of constantly hammering the same nail to get a swarm of mostly pointless comments. Do you really think that by doing that anything is going to change by doing that? I guess it is fair to say there is a lot a ST hype out there but jumping into the anti-hype wagon isnt going to help much.
    I, as many physicists do , expect the LHC to clear the way for science soon.
    And btw, the articles are fun reading 🙂

    G

  43. Jeff says:

    Garbage:

    You hit the nail! :-)) with your remark. The problem is that with excess time to spare, and not enough data to process, there really isn’t much else to discuss except the latest gossip on our favorite blogs; everything else lies suspended in animation. Only when LHC gives experimental results will the field move forward.

    As regarding string theory, I’ve heard rumors that even Ed Witten is beginning to have doubts (I can’t exactly pinpoint where I heard this from; maybe it was from Peter himself – referring to conversations between L. Susskind and Witten).

    Continuing, if you believe ST is a dead-end (or overhyped) then perhaps you may want to have a look through ‘twistor theory’. Roger Penrose, in his new book ‘The Road to Reality’ quite elegantly argues that physicists have grossly overlooked [and sometimes undervalued] the twistor approach in favor of strings (citing similar reasons as others, i.e. Witten’s overarching impact on current hep-th research, the sometimes unethical behavior of some string theorists when advocating the theory to lay audiences, string theory’s lion share of research funding – frequently at the expense of other meaningful approaches, the media hype over string theory, etc.); he also adds that twistor theory has some fairly deep and robust properties – grounded primarily on physical! (NOT mathematical) considerations – to uncover new insights into fundamental physics.
    [Penrose, as many may know, is twistor theory’s progenitor; however, given that he has spent more than 40+ years working on the topic, and given his calm and objective approach to writing on physics (as evidenced remarkably accurately in ‘Road to Reality’) I would not dismiss his claims as merely self-promotion; anyway, this *is* Roger Penrose we are talking about.]

    I guess if you are a serious grad student (or young researcher) and want a clearer understanding of the current (theory) research landscape, Penrose’s viewpoint may well not be an altogether bad start.

    Regards,
    Jeff

  44. Bert Schroer says:

    Garbage and Jeff
    I agree with you that there is to much gossip and not enough scientific substance in weblogs including this one.
    But I think that N=8 Supergravity is not a good illustration of this point. Why should a social construct like that be the subject of a meaningful discussion? Rumors about its possible renormalizability appear cyclically as reports on the sight of Nessy. Perhaps if somebody really succeeded to show nth order renormalizability it is worthwhile to talk about the physical significance of such an result but not in this stage.
    The monomaniac preoccupation with quantum gravity siphons power away from post SM innovative research and at the end also harms progress about gravity.
    If you look at my contributions of the recent weeks you will notice that I have been trying to get people interested in conceptual issues of actual research such as
    Is KK consistent with QFT (and ST for that matter)
    Why the CC computations of adding energies contradict local covariance
    Why the alleged connection of holography with QG is misleading and how this led to wrong conjectures about AdS—CFT (a la Maldacena)
    Why the objects of ST cannot be string-localized in any quantum-intrinsic sense
    I admit that all these points require a certain amount of conceptual sophistication and mathematical knowledge. But is this the reason why nobody took them up or even asked meaningful questions?
    I tried to adapt myself to the typical small talk on this blog with the subversive intention to lure people into more serious questions which could be the starting point of interesting discussions.
    I do not see any point in repeating the lack of observational content of ST over and over again. Most participants and readers know this deadly flaw and the ST community has developed a thick skin.

  45. JC says:

    Bert,

    Many folks I knew over the years felt that the biggest barrier to understanding algebraic QFT, even on a “qualitative” level, is the level of mathematics involved. Even with some knowledge of the mathematics involved, I’ve found that I still don’t have a good understanding of it.

  46. Tony Smith says:

    Garbage said that Peter has “… an interesting post on finiteness of N=8 SUGRA, which if true would certainly produce a (though unrealistic) more *traditional* finite theory of gravity, that doesnt count more than 8 comments.
    In the other hand, this one on early critics of ST clicks 40 in a few days … a swarm of mostly pointless comments. …
    This is why this blog misses the oportunity to be a good place to discuss physics. …”.

    Garbage fails to note that the first comment on this thread was NOT “pointless” with resepect to substantive physics, but in fact dealt with Nakanishi’s view of the fundamental status of the Heisenberg picture.
    Also, other substantive physics points have been mentioned in this thread, such as:
    Penrose’s twistor theory;
    Nakanishi’s use of indefinite metric;
    the consistency of Kaluza-Klein with QFT; and
    soft predictions from spin networks of deformed special relativity, elementary particles as coherent excitations of quantum geometry, and disordered locality, all discussed in hep-th/0605052 which was mentioned in comment 14 by dark-matter.

    Tony Smith
    http://www.valdostamuseum.org/hamsmith/

    PS – I note that Garbage him/herself has NOT submitted a comment to the thread on the finiteness of N=8 SUGRA, and HAS submitted a comment to this thread, and, further, posted the above-quoted comment as an AC.

  47. Bert Schroer says:

    JC
    This is not the whole truth. The mathematical prerequisites are certainly not more demanding than those in string theory where these days people use category theory, gerbs, algebraic geometry, noncommutative geometry…..
    I think the basic difference is that in ST you do not have to know their deeper mathematical content; the metaphoric physical nature of ST allows you to operate with a basically verbal knowledge and the rest can be done by improvisation and massage.
    AQFT continued von Neumann’s tradition on the mathematical side (but on a meanwhile infinitely refined level) and tries to implement the Jordan plea of disconnecting a more fundamental theory (QFT) from its classical bonds (the AQFT as conceived first by Haag). Its mathematics consists only of refinements of concepts which in their mode crude version you are certainly familiar with: bounded and unbounded operators, operator algebras and their spacetime encoding. It is the only setting of QFT in which there has been an independent development on par with mathematics on a very deep level of conceptual coalescence (the modular Tomita-Takesaki theory with an independent development from the center of QFT: the thermal theory of open systems by Haag Hugenholz and Winnink and the concept of modular localization which started with Bisognano and Wichmann). Using metaphors of physics for the advancement of mathematics or using existing mathematics to expand metaphors of physics is not the same thing.
    The distance which people maintain from AQFT has little to do with its high demands on mathematics; it is more related to sociology and history. The same people who have to take responsibility for the post SM hubris are also those who consider it as a superfluous distraction from their grand design.

  48. Particle Physicist says:

    “The same people who have to take responsibility for the post SM hubris are also those who consider it as a superfluous distraction from their grand design.”

    It is also the people who developed the SM who consider AQFT as a superfluous distraction, and fortunately so. Otherwise, we wouldn’t have QCD and a theory of electroweak interactions today but were still stuck in the 50’s, roughly speaking. Or can you point to any insight into the SM that was provided by AQFT?

  49. Bert Schroer says:

    I was not talking about the ideas which led to those important discoveries, the hubris started afterwords. I never felt any antagonism before but rather a division of labor. There are those who go out and find our truffles and there are others who like to clarify and secure these findings in order to build a reasonable trustworthy basis for starting new discoveries and this has never had a stifling influence on the truffle seekers. The discovery of gauge theories was very important but the situation is a long way off from being in the possession of a trustworthy basis for the conquest of new phenomena (and I am reluctant to say this, in the present conceptual quicksand even the future results of LHC may not indicate the way out).
    The point of view you are presenting is part of that post SM hubris. I suggest to you to read what Phil Anderson has said about this problem.

  50. Particle Physicist says:

    Let me repeat the question: what insights related to standard model physics, and beyond, would we miss if no one ever had dealt with AQFT?

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