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I Why String Theory Is Still Not Even Wrong

  1. Apr 30, 2017 #1
    Horgan: Do you still think string theory is “not even wrong”?

    Woit: Yes. My book on the subject was written in 2003-4 and I think that its point of view about string theory has been vindicated by what has happened since then. Experimental results from the Large Hadron Collider show no evidence of the extra dimensions or supersymmetry that string theorists had argued for as "predictions" of string theory. The internal problems of the theory are even more serious after another decade of research. These include the complexity, ugliness and lack of explanatory power of models designed to connect string theory with known phenomena, as well as the continuing failure to come up with a consistent formulation of the theory.

    Horgan: Why do you think Edward Witten told me in 2014 that string theory is “on the right track”?

    Woit: I think the conjectural picture of how string theory would unite gravity and the standard model that Witten came up with in 1984-5 (in collaboration with others) had a huge influence on him, and he's reluctant to accept the idea that the models developed back then were a red herring. Like many prominent string theorists, for a long time now he no longer actively has worked on such models but, absent a convincing alternative, he is unlikely to give up on the hope that the vision of this period points the way forward, even as progress has stalled.

    https://blogs.scientificamerican.com/cross-check/why-string-theory-is-still-not-even-wrong/

    any string theorists would like to reply, esp to the claim

    "The internal problems of the theory are even more serious after another decade of research. These include the complexity, ugliness and lack of explanatory power of models designed to connect string theory with known phenomena, as well as the continuing failure to come up with a consistent formulation of the theory."

    with specific evidence?

    I want to be exposed to opposing points of view.
     
  2. jcsd
  3. May 1, 2017 #2

    martinbn

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    Complexity and ugliness! How can these, especially the second which is as subjective as it gets, be problems?
     
  4. May 1, 2017 #3
    bc ugliness violates occam's razor
     
  5. May 1, 2017 #4

    Drakkith

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    I don't think I agree, but perhaps Woit's use of the word "ugliness" here means something less subjective that does fit Occam's Razor.
     
  6. May 1, 2017 #5

    julian

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    String theory advocates, to this day, are guilty of trying to claim the full complexity of the world follows from an extremely simple picture. If they know this isn't true then stop doing this.
     
  7. May 1, 2017 #6

    Standard Model-Axion-Seesaw-Higgs Portal Inflation solves dark matter, neutrino oscillations, baryogenesis, inflation and the strong CP problem with just standard QFT and in 4D w/o SUSY.

    i.e start with the SM in 4D QFT then add the fewest number of additional particles and fields to address the remaining mysteries dark matter, neutrino oscillations, baryogenesis, inflation and the strong CP problem.

    vs string theory which requires MSSM or some variation + GUT of some kind + extra dimensions, then finding a way to avoid falsification from LHC latest results.
     
  8. May 1, 2017 #7
    Agreed. String theory is not even, well....a Theory. At least not in the scientific sense of the word. Rather, it is a hypothesis at best.

    A theory needs to have put forth postulates that were later confirmed and proven.

    So far as I know, ST had not done this. It's all speculative in nature.

    It actually poses more questions than it answers!


    The fairly recent discovery of the Higgs Boson at CERN did the ST hypothesis no favors, either.

    I consider St to be Pop Physics.

    It's fifteen minutes should be up soon. I thought it pretty much was, after the Brian Green Elegant Universe thing went out of Vogue
     
  9. May 2, 2017 #8

    haushofer

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    Ugliness depends on your mathematical framework. Try doing QED without gauge invariance, or GR without a clear understanding of differential geometry.

    As my mother once told me: never judge a theory from the outside.
     
  10. May 3, 2017 #9

    haushofer

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    How should we ever know whether this is true or not? I regard it as a matter of induction; looking at history, unification often kicks in when we go to higher energy scales. And that's what scientists do: try whatever worked in the past.

    Personally, I think string theory has some remarkable properties which still makes it worthwile investigating in. One of them being the fact that it is a quantum theory which requires gravity to be consistent. Or, as is sometimes stated: it postdicts gravity.
     
  11. May 3, 2017 #10
    gravity in 11 dimensions
     
  12. May 4, 2017 #11

    haushofer

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    Well, not exactly; anomalies also disappear in 3 dimensions :P

    But those extra dimensions are also necessary to make contact to realistic models. If string theory would be only be consistent right away in 3+1dimensions, we would have no hope to extract the standard model from it.
     
  13. May 4, 2017 #12

    perhaps thats why string theory is wrong. the correct theory of nature should uniquely give rise only to the standard model in 3+1 dimensions.
     
  14. May 4, 2017 #13

    atyy

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    Woit is wrong. String theory could be wrong. Even if it is wrong, its place in future physics is secure, and at least analogous to the place of Nordstrom's theory of gravity in today's physics. The developments from the Ryu-Takayanagi formula from around 2006 show that progress in string theory continues.
     
  15. May 4, 2017 #14
    does string theory make any falsifiable predictions such that if an experiment or observation is done, the theory is falsified?

    e.g if we build a collider up to planck scale energies, and no SUSY shows up, does this falsify SUSY and string theory?
     
  16. May 4, 2017 #15

    atyy

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    Some parts of string theory have already been falsified. Yet these false models remain much studied because they are our best candidates for a complete theory of quantum gravity in some universe.
     
  17. May 4, 2017 #16
    This claim that strings give a theory of quantum gravity was questioned by Woit or Smolin (don't remember) too, with the claim that 1.) a proof is given only for a few low order terms, not for all, and 2.) this is anyway irrelevant because it requires exact supersymmetry, which is not viable. IIRC.

    Has anything changed in this direction?

    If not, what would be the point of QG being something in favor of strings? Anyway it does not work. While in fact QG is not a big problem if one thinks about it as an effective field theory. Throw away the problematic diff invariance, say, by introducing harmonic coordinates, and you have a normal field theory on some fixed background, then use a lattice regularization and you have some theory of QG.

    So, having some theory of QG is not really problematic (one may not like this proposal, but so what), but string theory does not even have a viable well-defined one.
     
  18. May 4, 2017 #17

    arivero

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    Well, lets hope that at some time they will care to look to the lot of structure happening at the electroweak scale, instead of hoping to get all the rabbits out of the GUT scale hat.
     
  19. May 4, 2017 #18
    how does string theory deal with the problem of time, with the different conception of time in GR vs QM?
     
  20. May 4, 2017 #19
    I found a picture of space-time in higher dimension (by Max Tegmark)
    Adsız.png
    I dont know the time dimension prediction of the string theory.But here says after 3 space dimension (In 1 time dimension case) the universe becomes unstable.What this suppose to mean ?
     
  21. May 5, 2017 #20

    haushofer

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    Why 'uniquely' and why could the 3+1 not just be an effective description?
     
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