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Tuesday, January 22, 2019

Letter from a reader: “Someone has to write such a book” we used to say

Dear Sabine,

congratulations on your book. I read it this sommer and enjoyed it very much. For people like me, working on solid state physics, the issues you addressed were a recurrent subject to talk over lunch over the last decade. “Someone has to write such a book” we used to say, necessarily had to be someone from inside this community. I am glad that you did it.

I came to your book through the nice review published in Nature. I was disappointed with the one I read later in Science; also, with the recent one on Physics Today by Wilczek (“...and beautiful ideas from information theory are illuminating physical algorithms and quantum network design”, does it make sense to anyone?!). To be honest, he should list all beautiful ideas developed, and then the brief list of the ones that got agreement with experiment. This would be a scientific approach to test if such a statement makes sense, would you agree?

I send you a comment from Philip Anderson on string theory, I don’t think you mention it in your book but I guess you heard of it.

Best regards,

Daniel

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Prof. Daniel Farias
Dpto. de Física de la Materia Condensada
Universidad Autónoma de Madrid
Phone: +34 91 497 5550
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[The mentioned comment is Phillip Anderson’s response to the EDGE annual question 2005: What do you believe is true even though you cannot prove it? Which I append below for your amusement.]

Is string theory a futile exercise as physics, as I believe it to be? It is an interesting mathematical specialty and has produced and will produce mathematics useful in other contexts, but it seems no more vital as mathematics than other areas of very abstract or specialized math, and doesn't on that basis justify the incredible amount of effort expended on it.

My belief is based on the fact that string theory is the first science in hundreds of years to be pursued in pre-Baconian fashion, without any adequate experimental guidance. It proposes that Nature is the way we would like it to be rather than the way we see it to be; and it is improbable that Nature thinks the same way we do.

The sad thing is that, as several young would-be theorists have explained to me, it is so highly developed that it is a full-time job just to keep up with it. That means that other avenues are not being explored by the bright, imaginative young people, and that alternative career paths are blocked.

21 comments:

  1. bee:

    i just wanted to note for your readers, that P.W. Anderson is one of the major proponents of 'emergent' physics (i.e. he is an anti-reductionist) and his manifesto "More Is Different")

    http://robotics.cs.tamu.edu/dshell/cs689/papers/anderson72more_is_different.pdf

    is well worth reading .

    IMO string theory, the multiverse and their ilk (as discussed in your outstanding book) are as much the inevitable result of the reductionist approach to doing theoretcal physics as Trump is the inevitable result of representative democracy of the American political system (although i expect that physics is more likely to recover from its philosophical mis-step through experiment (phenomenology)which will (hopefully) serve as a self-correcting mechanism.

    naive theorist

    ReplyDelete
    Replies
    1. These results reported by Anderson in the physics of complex systems have been given mathematical precision by Gregory Chaitin and others in Information-Theoretic Incompleteness, it seems that complexity is a source of incompleteness, or that complex systems will exhibit "strong emergent" properties; but after Godel showing that apparently simple axiomatic systems are intrinsically incomplete it will be wishful thinking and very naive to think that Reality will "behave" better.
      Reductionism has intrinsic limitations obviously, theoreticians hope of a "theory of everything" or "final theory" are, it seems, unobtainable dreams and ultimately dogmatic dreams, the scientific endeavor is never ending.

      Thanks for the reference.

      Delete
  2. bee:

    i just recalled a quite accurate (IMO) description of the current state of foundational physics by Woody Allen

    https://www.youtube.com/watch?v=bphR-6Xi1_I:

    naive theorist

    ReplyDelete
  3. @Daniel
    I disagree with your criticism of Wilczek's
    review. Firstly he agrees with your disdain
    of areas of physics that have lost contact
    with experiment, like e.g. string theory.
    But truly fundamental insights into physics,
    that were confirmed by experiment (like e.g.
    Wilczek's brainschild: QCD) always seemed beautiful to
    competent physicists.
    Even Sabine admits that in the last 2 sentences
    of her book:
    "The next breakthrough in physics will occur
    in this century. It will be beautiful."

    @Sabine What did you mean with these sentences?

    Wilczek is very nice in his review by
    calling the fact that Sabine seems not to believe
    in her own agitation against "beauty" an "unfortunate terminology".

    ReplyDelete
  4. Unknown,

    You make the very same mistake I laid out in my book, you pick examples where a supposedly beautiful idea worked and ignore the cases where beautiful ideas did not work. This isn't a good way to evaluate evidence, it's a documentation of confirmation bias.

    Those last sentences in my book say that I think we will make further breakthroughs and that we will come to find the new theories beautiful. Finding beauty in scientific discovery per se is not the problem. Problems occur if scientists come to use specific definitions of beauty and rely on those (despite evidence that those are not working).

    I have been exceedingly clear in my book exactly what specific types of beauty are the problem.

    ReplyDelete
  5. Imagine the idea of SUSY would have been
    experimentally confirmed: particles with O(100) GeV mass
    that make the SM natural and turn out to explain DM were found at Fermilab
    in 2003.
    YOU would have found that beautiful.
    Right? Admit it.

    But then your colleagues were not led by some "false sense of beauty".
    You're bashing them for having to few
    not to many beautiful ideas. Wilczek is right.
    You were a well funded member of
    your community in the last 15 years and also
    failed to come up with anything.
    Given sufficient funding you would very much like
    to continue to try until you're 67. Right?
    Admit it.

    But then how can you agitate against your 30 year old
    colleagues (e.g. at CERN) who want to do
    the same? Clearly for this they need the FCC or
    something better.

    ReplyDelete
  6. Unknown,

    You say "But truly fundamental insights into physics ... always seemed beautiful to competent physicists."

    Always? Beauty is very much in the eye of the beholder and subject to fashion. As Roger Penrose has said:-

    "...when we try deliberately to use the criterion of mathematical beauty in formulating our theories, we are easily led astray. General relativity is certainly a very beautiful theory, but how does one judge the elegance of physical theories generally? Different people have very different aesthetic judgments. [...] Moreover, the inherent beauty in a theory is often not obvious at first, and is revealed only later when the depths of its mathematical structure become apparent through later technical developments.”

    ReplyDelete
  7. Unknown,

    Of course my sense of beauty is not much different from those of other people in the field. I have been part of the same community. I read the same books, I heard the same talks. I am not saying that supersymmetry and string theory (etc) are not beautiful. I am saying it doesn't matter. It's not a scientific criterion. Physicists shouldn't use it. I am trying to follow my own advice, which is why I've stopped working on BSM pheno.

    I am not "agitating" against anyone. I'm just telling you the truth. Those predictions aren't worth anything. One can't trust them. Look at the facts.

    ReplyDelete
  8. There are so many examples of beautiful ideas that at the end dont match experiment. Just to give an example, I quote here a celebrated CERN scientist, John Bell, talking about the EPR experiment (he uses the word "rational" but means the same thing):

    "For me, it is so reasonable to assume that the photons in those experiments carry with them programs, which have been correlated in advance, telling them how to behave. This is so rational that I think that when Einstein saw that, and the others refused to see it, he
    was the rational man....I feel that Einstein’s intellectual superiority over Bohr, in this instance, was enormous; a vast gulf between the man who saw clearly what was needed, and the obscurantist. So for me, it is a pity that Einstein’s idea doesn’t work. The reasonable thing just doesn’t work.’’ (from J. Bernstein, "Quantum profiles", p.84)

    It happens quite often: the reasonable (and beautiful) thing just doesn't work!

    Daniel Farias

    ReplyDelete
  9. @RGT
    Yes always. Because beauty is simplicity. We call
    a simple theory beautiful if it explains a lot.

    @Sabine
    Of course one cannot "trust" beautiful predictions.
    Sometimes they are confirmed, sometimes
    they are not. The problem is that there were too few (actually 0)
    beautiful predictions in the last 30 years. Exactly as Wilczek says.
    The community was not clever enough, and you were a member
    of this community. There is no base for your anger except
    for being angry that you yourself are not clever enough.

    ReplyDelete
  10. Unknown,

    I am very clear in my book with explaining what beautiful theories in the past 30 years led to wrong predictions. Since you do not seem to have read the book, maybe let me allow to clarify that I did interview Wilczek and asked him what he thinks makes a theory beautiful.

    I am not angry and I am happy with my research. Your amateur-psychology is off the mark.

    ReplyDelete
  11. Unknown,

    As a thought experiment imagine yourself a 'physicist' in 1865. Along comes an upstart who puts forward a 'theory' linking electricity and magnetism. The theory challenges accepted norms of physics and mathematical beauty - specifically Newton's concept of objects interacting at a distance - with a mysterious universal 'field'. The mathematics to make all this work is extremely complicated, and the notation used even worse. Basically the theory is just one more idea of how electricity and magnetism are linked. It does not fit your conception of beauty as defined by Newtonian mechanics, it's fiendishly difficult and you've better things to do with your time. What's your verdict on this theory which by all the standards of your time has to be called ugly?

    Twenty years and a generation later Maxwell's equations achieved a certain prominence. Now the theory is one of the bedrocks of modern physics. But even so is it Maxwell's first construction that's 'beautiful' or subsequent iterations?

    Beauty, like time, is relative.

    ReplyDelete
  12. Unknown wrote: Given sufficient funding you would very much like to continue to try until you're 67. Right? Admit it.

    What kind of a question is that? Sabine doesn't object to physicists getting paid to do productive work. And it's odd for you to suggest that it's all about getting to 67, as if it's only about making it to retirement.

    Unknown wrote: how can you agitate against your 30 year old colleagues (e.g. at CERN) who want to do the same?

    Do the same what? Sabine isn't agitating against physicists doing research.

    ReplyDelete
  13. Unknown wrote: The problem is that there were 0 beautiful predictions in the last 30 years. The community was not clever enough.

    So if physicists were more clever they would have made beautiful predictions?

    Unknown wrote: Exactly as Wilczek says.

    Did Wilczek say physicists were not clever enough? I've met Wilczek and his wife and they both seemed pretty clever to me.

    ReplyDelete
  14. Unknown,

    You said 'always'. Implying from first presentation of the theory. I challenge you to give an example where the initial theory was immediately accepted by all competent physicists of the time.

    As regards all simple theories are beautiful. Again, what is simple after a period of reflection and learning can often be fiendishly difficult on first presentation. Competent physicists may (will often) take a period of time to consider, reflect and accept.

    Theories may become accepted as 'true', beautiful and simple after a period but to claim 'always' means from day 0. The period may be short or long (nearly 100 years in Newton's case, twenty years in Maxwell's) but it is 'always' there.

    ReplyDelete
  15. @RT:

    you might want to look at:

    Studies in History and Philosophy of Modern Physics 43 (2012) 236–257
    Maxwell’s contrived analogy: An early version of the methodology of modeling

    naive theorist

    ReplyDelete
  16. @Sabine
    I did read your book. In your interview Wilczek equated beauty
    with conceptual simplicity. As we all do.

    @RGT
    The subsequent iterations just made the
    beauty of Maxwell's theory more obvious.
    "always" != "immediately"


    @Steven
    I wrote "in the last 30 years". Wilczek made
    his beautiful predictions ca. 45 years ago.
    Do you realize that Sabine is terrified
    that she will soon no longer "getting paid to do productive work"?
    Young CERN experimentalists can't do research during their work life
    (i.e. until 67) without the FCC or something better.

    ReplyDelete
  17. Now that you mention Maxwell's equations, I always thougth that the truly beautiful thing would be to have full-symmetric equations (magnetic monopoles), but this is the viewpoint of a naive experimentalist working on a non-fundamental area of physics (by the way, an area that received roughly 50% of physics Nobel prizes). I guess people working at CERN have a convincing argument against this naive point of view.

    ReplyDelete
  18. naivetheorist

    Not at all sure of your point, other than providing an interesting reference.

    "What Maxwell contrived as an artifact to explain electricity and magnetism would potentially provide a rigorous dynamical theoretical basis for the emerging field of fluid flow in porous media. Yet, as history would have it, his work went largely unnoticed. Something similar to it would not be proposed
    in the literature until 1940."

    ReplyDelete
  19. Daniel Farias asks whether Wilczek's sentence “...and beautiful ideas from information theory are illuminating physical algorithms and quantum network design” even means anything. I would assume he means that beautiful ideas are still working to discover new phenomena in quantum information and computation. His previous sentence said that beautiful ideas are still working in condensed matter physics.

    But both of these cases are different, in that these areas are guided not only by beautiful ideas, but also by experiments. And (interposing my own discipline) mathematics works from beautiful ideas and proofs. It's in high-energy physics, where the only guide they have is beauty, that researchers have lost their way.

    ReplyDelete
  20. Daniel, Peter,

    Fwiw, I think he is referring to this stuff and related ideas.

    ReplyDelete

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