String Universality Reloaded

I still haven’t figured out yet what the arXiv’s trackback policy is, since trackbacks to my blog entries sometimes appear there, sometimes not. One example in the “not” category is my recent posting about the Kumar-Taylor paper on “String Universality”, which now has trackbacks to postings by Jacques Distler (recently seen here) and Dmitry Podolsky. The ways of the arXiv remain mysterious, but I can’t help recalling that my original problems with them seemed to have to do with powerful people who did not like having their multiverse pseudo-science disrespected. Even without the trackback, I’m wondering if the authors of the paper somehow heard about my comments and felt they needed to be addressed, since a new version of the paper has just appeared.

The most extensive changes are to the section on “predictivity” discussed in my posting. Here’s some of the added text:

It may be that string universality holds for four-dimensional theories with supersymmetry, but that supersymmetry breaking mechanisms lead to a constrained subset of non-supersymmetric low-energy theories in 4D.

It is possible that the dynamics of string cosmology may define a natural measure on the space of string solutions, which would favor some solutions over others. Currently, however, we lack a mathematically complete or background-independent formulation of string theory. It is likely that significant progress in this direction will be needed to understand the cosmological measure on the string landscape. In this brief discussion, we describe the situation for predictivity in the absence of such a breakthrough.

Some other changes:

This may seem like a very awkward situation for string theory.

has been replaced by

If we were living in six dimensions, then this would seem like a very awkward situation for string theory.

and the assurance that string theory would explain anything seen at the LHC has been toned down a bit, with

any new and unexpected phenomena found in experiments at higher energies should be realizable in the string theory context

replaced by

any new and unexpected phenomena found in experiments at higher energies may be realizable in the string theory context

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17 Responses to String Universality Reloaded

  1. Sakura-chan says:

    100% off topic, but when you search for “terence tao” on google, the two related search suggestions at the bottom are grigori perelman and not even wrong.

  2. Tom Whicker says:

    The comments from Clifford Johnson and Jacques Distler are defensive; at times almost desperate. The level of denial
    is palpable.

    Even though string theory is now more than 30 years old, Clifford claims that it cannot be questioned because it is still in naiscent form and must be protected from prying eyes:

    “The point, Peter, is that we don’t know whether it is right or wrong either, nor what the outcome of the entire program of research will be, ultimately. But we’re not (or at least, that large percentage of the field I know and trust) are not presuming the answer at the outset, like you are. That’s why it is called research. We don’t know.

    But next he turns 180 degrees and lambasts critics of string theory, saying they do not speak with enough detailed
    equations and scientific rigour:

    “So, Peter, come out from behind that silly figleaf and tell us: How is the actual scientific argument for your claims coming along then? Have you written a paper yet? Constructed a demonstration the community can discuss? Is anyone going to see it soon?
    Try to do some science, Peter. Please try. Back up your claims with science and not obfuscation if you want them to be taken seriously. Until then, you’re wasting everyone’s time.”

    All the while Clifford proudly proclaims that he is just too busy to read either book from Woit or Smolin.

    The taunting, sneering tone from Johnson and Distler is something I haven’t heard since teenage locker-room days.
    If this is what the world of academic physics has come to; I’m so glad I left that world some time ago!

  3. George Dorn says:

    I am also flabbergasted at the tone used by what would appear to be grown up people on various blogs devoted to what would appear to be science and scientific arguments. If nothing else going back and reading all this stuff has provided hilarious entertainment. I have always been a little sceptic when historic accounts of scientific breakthroughs presented the community as conservative and childishly clinging to old ideas but I must admit that it all seems so much more plausible in the light of all these exchanges.

  4. Peter Woit says:

    Tom Whicker,

    One of the most surprising things to me about the “String Wars” has been the strange behavior of the few well-known string theory bloggers. Besides the Distler/Johnson business, there’s always Lubos, whose activities (see next posting) seem to embody Hunter Thompson’s slogan “When the going gets weird, the weird turn pro.”

  5. Arnaud says:

    Is String Theory really 30 years old? That would mean papers before 1980?

    A.

  6. Peter Woit says:

    Arnaud,

    Work on string theory as a theory of the strong interactions started in 1970, as a unified theory including gravity 1974. It was only in 1984 that it became incredibly popular, once Witten started working on it. We’re about to hit the 25th anniversary of that event…

  7. nbutsomebody says:

    Lubos is a lunatic, and right now he is somehow out of scientific community. His views may well be dismissed as paranoia. However I am shocked to see how comparatively well respected guys like Clifford Johnson etc behave towards criticism. It is really a shame to string theory community, a big shame.

  8. GR says:

    Ostensibly string theorists are funded by NSF-type grants, and apparently have been for the past 20 years… is there no one at the institutions that’s asked for tangible results? Or is the problem that almost everyone in HEP theory these days is doing string theory?

    As a grad-school-bound student, I can safely say that the diatribes by people like Lubos and Johnson are a big turn off for theory in general and HEP in particular. I (naively and optimistcally) want to do science and discover something new and cool, not bicker endlessly about what the “right” way to do physic is. I don’t want to immerse myself in what (again, from an outsider’s perspective) looks like groupthink and wagon-circling.

    And I know most undergraduates feel the same way about string theory. We’re not dumb, we read PT and blogs. In the end, string theorists might have doomed themselves through this nasty and childish behavior.

    Also, as a side note, what’s with the proliferation of extra dimensions? What’s the historical justification for this avenue of research? Has anyone ever been able to show something about 4D from all this n-dimensional balderdash?

  9. nbutsomebody says:

    “Has anyone ever been able to show something about 4D from all this n-dimensional balderdash?”

    No, not in anything related to unification and standard model.

    However there is something called holography. Which may help us to aspects of gauge theory like QCD.

  10. anon says:

    “We’re not dumb, we read PT and blogs.”

    You contradict yourself.

  11. Rhys says:

    “However I am shocked to see how comparatively well respected guys like Clifford Johnson etc behave towards criticism. It is really a shame to string theory community, a big shame.”

    So because I’m studying string theory I should feel shame at the actions of others engaging in the same pursuit? That’s absurd, but it is not unusual to see this attitude endorsed, implicitly or explicitly, in various blogs (posts and comments).

    But to comment in dot points on the actual subject matter of the post:
    – As Peter admitted, the paper has no bearing on models of 4D physics.
    – The paper seems only to deal with the low energy theory (‘massless’ fields, roughly speaking). Stringy signatures will always appear at the compactification or string scale.
    – Nothing seems to have been proved.
    – It would be worth working on string theory, as a theory of quantum gravity/geometry, even if it could produce all low-energy effective theories.
    – I agree that if the swampland is empty, low-energy model building from string theory is somewhat pointless.

  12. nbutsomebody says:

    Rhys,
    I agree to your physics points. However you said
    “The paper seems only to deal with the low energy theory (’massless’ fields, roughly speaking). Stringy signatures will always appear at the compactification or string scale.”
    This is not strictly true. It depends on the particular theory.

    “So because I’m studying string theory I should feel shame at the actions of others engaging in the same pursuit? That’s absurd, but it is not unusual to see this attitude endorsed, implicitly or explicitly, in various blogs (posts and comments).”

    If you are just “studying” string theory, you may not have to bother about them. However, if you are a “string theorist”, you may have to share a little responsibility. There is nothing absurd about it, your credulity and scientific standard is indeed judged (at least in part) by looking at the scientific community you belong to. Look these guys are not some nuts who are doing fringe science. They are the main stream guys. People read their papers, they arrange conferences, they have money to heir postdocs/visitors/students. They appear in front of press, they act as refree and the list goes on and on. Like it or not they are the spoke person for the community, hence if you belong to the community they speak for you too :(. Only way to get rid of this uncomfortable situation, I believe, is a overt opposition to their erratic behavior.

  13. Peter Woit says:

    Rhys,

    What I find remarkable here are not the arguments over remaining hopes that string theory somehow can say something about particle physics, but the notion that “string universality” is somehow a positive thing, rather than a simple expression of failure. When an idea doesn’t work, you’re supposed to give up on it, not promote it as some new kind of science.

  14. anon. says:

    ‘When an idea doesn’t work, you’re supposed to give up on it, not promote it as some new kind of science.’

    As people keep pointing out, dogmatic belief systems with no evidence from start to finish like religions, don’t operate like rational science. When they fail to a achieve something, the failure is interpreted as a proof of decisive knowledge that it is impossible for anybody ever to achieve that thing.

    E.g., if string theory can’t predict everything, then that’s not the failure of string theory. It’s proof that nature is simply not predictable. Don’t you see that, you fucking moron?

  15. Mitch Miller says:

    Peter,

    I apologize in advance as this is pretty far off topic, but I have a question on the slides that you posted on the other thread. On slide 30 you say that violations of WW scatering at the LHC could actually be good for string theory, I don’t see how that is possible. The standard model is already falsified because of gravity, what is not known is the energy scale at which naive GR+SM stops being valid. If violations are found, it seems like string theory would be dead since AFAIK string theory can’t handle Lorentz breaking at this (possibly any?) scale or unitarity/analyticity breaking.

    I think I agree with the spirit of what you are saying, this is sort of lame as a test of ST since it is such a long shot to begin with but I’m not sure if I am missing something else. And feel free to ignore/delete if too off topic. Thanks.

  16. Peter Woit says:

    Mitch,

    The only point I was trying to make was that the claim made in that case about a test of string theory was actually about a test of basic QFT axioms. There was an argument on various blogs about this way back when, but it still seems to me that a Lorentz-breaking string theory ground state is possible. Unlike QFT, you don’t have a non-perturbative definition, or agreed upon axioms.

    As a matter of sociology, I am quite convinced that if the LHC sees something that violates QFT axioms, this will be touted as evidence for string theory…

  17. Mitch Miller says:

    Thanks, that clears it up. It will be very interesting to see how people react if something crazy actually does happen at the LHC.

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