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Insights Interview with a Theoretical Physicist: Sabine Hossenfelder - Comments

  1. Mar 26, 2017 #1
  2. jcsd
  3. Mar 26, 2017 #2

    martinbn

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    I am surprised that she has never heard that the models are commonly regarded as simple and beautiful. Aren't they?
     
  4. Mar 26, 2017 #3
    Martin, where have you seen such comments on the models?
     
  5. Mar 26, 2017 #4
    Very good article. @Greg Bernhardt I wanted to give my vote and give it a "5", but I don't see anywhere I can click on to vote....
     
  6. Mar 26, 2017 #5
    What are your views on Loop quantum gravity, and should top Universities like Princeton, Harvard, MIT, Stanford sponsor a loop quantum gravity research group and faculty?

    Loop quantum gravity is even more detached from physics than is string theory, and the math is less interesting on its own right. No, I wouldn’t recommend to any university to set up a research group on loop quantum gravity. If some department is interested in quantum gravity, they should set up a research group on quantum gravity phenomenology, and hire people to take on the question how to find experimental evidence that gravity is even quantized. (And, at some point, find out which theory of quantum gravity is the correct one.)

    Reference https://www.physicsforums.com/insights/interview-theoretical-physicist-sabine-hossenfelder/

    i'm glad you asked the question i've asked.

    i'm sure abhay ashketar or smolin or rovelli would disagree.

    given sabine's answer

    what about loop quantum cosmology's contact with observation in CMB and other observable?

    what about loop quantum gravity reproducing hawking entropy and radiation?

    what about asymptotically safe gravity, noncommutative geometry, causal dynamic triangulation etc?

    should universities that do have LQG research groups and LQG researchers like penn state shut down their LQG research group and fire abhay ashketar et al?

    since the LHC found no evidence of SUSY, and proton decay has found no evidence of proton decay as predicted by GUT's

    Should universities that do not currently have a string theory research group, set one up in light of current LHC SUSY results?
     
  7. Mar 27, 2017 #6
    Even as a layperson reading pop-sci accounts, I retain a strong impression that over the years, some inside physics have complained of the un-tidyness of various modern models; that smacks of an aesthetic argument.

    Beyond that, mathematics famously has aesthetic appeal; and since physics relies so heavily on math, it wouldn't be surprising that some researchers and authors inside physics would say the same, at least in pop-sci presentations. I did a quick Google and "symmetry" seems particularly mentioned. Here are just a few hits out of many:

    - A PBS-related article: Symmetry: How Beautiful Math Makes Elegant Physics

    - A particular physicist's pop-sci book: Deep Down Things: The Breathtaking Beauty of Particle Physics (re: the standard model)

    - Another book, with a Penrose forward: Fearful Symmetry: The Search for Beauty in Modern Physics

    Feynman too seems, in his recorded remarks and interviews, to hint here & there at aesthetics; the difference is, I doubt he would have insisted on it in relation to usefulness. Indeed, in his lecture on harmonics, he says this:
     
    Last edited: Mar 27, 2017
  8. Mar 27, 2017 #7

    martinbn

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    I didn't mean the latest speculative models, I mean mathematical models in general and throughout history. For example Dirac (and many others) has always maintained such a view.
     
  9. Mar 27, 2017 #8
    Following up on this - Wikiquote has some particularly toothsome remarks by Dirac along these lines; they are taken from a 1963 article by him in Scientific American. The article was reprinted in 2010 and can be found here; the title is "The Evolution of the Physicist's Picture of Nature". These quotes are pulled directly from the article; bold is mine:

    . . . There is one other line along which one can still proceed by theoretical means. It seems to be one of the fundamental features of nature that fundamental physical laws are described in terms of a mathematical theory of great beauty and power, needing quite a high standard of mathematics for one to understand it. You may wonder: Why is nature constructed along these lines? One can only answer that our present knowledge seems to show that nature is so constructed. We simply have to accept it.​

    . . . It seems that if one is working from the point of view of getting beauty in one's equations, and if one has really a sound insight, one is on a sure line of progress. If there is not complete agreement between the results of one's work and experiment, one should not allow oneself to be too discouraged, because the discrepancy may well be due to minor features that are not properly taken into account and that will get cleared up with further developments of the theory.​

    Clearly Dirac was expressing a preference only; his argument goes no deeper than that. So even in his time others might have dismissed such a view as irrelevant, just as they might today. This is besides the fact that beauty is subjective.
     
    Last edited: Mar 27, 2017
  10. Mar 27, 2017 #9
    A related question might be whether Occam's razor (which I would argue is rooted in aesthetics) has any real utility; this blog piece presents a good argument against its over-use in physics and other branches of science: Why The Simplest Theory Is Never The Right One: Occam’s Razor Has A Double Edge. Here's a quote; the bold is mine and highlights the relevance to this thread:

    Theories with the fewest assumptions are often preferred to those positing more, a heuristic often called “Occam’s razor.” . . . But there are numerous reasons to suspect that this simple “theory of theories” is itself fundamentally misguided. Nowhere is this more apparent than in physics, the science attempting to uncover the fundamental laws giving rise to reality. The history of physics is like a trip down the rabbit hole: the elegance and simplicity of Newtonian physics has been incrementally replaced by more and more complex theories. At the time of writing, this has culminated in M-Theory, positing no less than 10 dimensions of space and the existence of unobservably small “strings” as the fundamental building block of reality. It seems safe to assume that the fundamental laws of reality will be even more complex, if we can even discover them.​
     
  11. Apr 17, 2017 #10
    Nice overall interview. But this must probably the dumbest thing she ever said:

    I have never heard of the fact that “physical models are commonly regarded as beautiful and in a sense minimal” and even if that was so I don’t know why it would matter. Yes, quite possibly it’s a pretty bad idea to rely on the aesthetic sense of humans to find a good theory to describe nature.



     
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