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Living Opponents of the Copenhagen Interpretation

  1. Nov 10, 2014 #1
    I was wondering if anyone could tell me who are considered the leading opponents of the Copenhagen Interpretation who are alive today?--and even what would be the best way to get myself some formal physics education under such individuals?

    I would love to learn more about physics, although I do not have any formal education in it. I do have a masters degree in education and bachelors in business. Is it possible for someone in my position to go straight to a masters? PhD? I have considerable informal learning in philosophy and philosophy of science, and a bit in physics (I've spent about 10 years in relative isolation in Nepal and spent much of my waking hours reading during that time).

    Even though I don't have formal training in physics (and thus in one sense have no right to have a strong opinion), I still can't help but strongly feel based on what I understand that the Copenhagen Interpretation is not only based on a purely philosophical assumption--but an error. And I believe that predictive accuracy does not necessarily vindicate philosophical assumptions (to say nothing for errors).

    But--granted--I have not been able to understand Bell's theorem and how the Aspect (and following) experiments are supposed to have vindicated the CI in light of it--which, as I understand, is the real heart of the argument.

    Thus, I am eager to learn. On the one hand, I am willing to change my mind if the Bell-Aspect argument really is as strong as I have heard it is. But on the other hand, I almost can't even imagine it can vindicate what appears to me to be the grossest of philosophical errors (the empircal criterion of meaning, which is now all-but universally recognized in philosophy to be self-refuting) which underlay the origins of the Copenhagen Interpretation.

    Sorry if anything here gives offense, and I crave instruction and guidance, so thanks for any help anyone can give!
     
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  3. Nov 10, 2014 #2

    atyy

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    Opponents of Copenhagen are either crackpots or Ballentine (and Ballentine is wrong).

    The Copenhagen interpretation has not been falsified. All interpretations of quantum mechanics must have the Copenhagen interpretation as emergent. Thus for example, Bohmian scenarios do not oppose Copenhagen, rather the Copenhagen interpretation is emergent from Bohmian mechanics.

    Some versions of Copenhagen have had errors, namely the versions that claimed that hidden variables were impossible, following von Neumann's erroneous proof. No modern versions make such a claim.

    The Copenhagen type interpretation is also called "operational" or "instrumental", and apart from the orthodox shut-up-and-calculate interpretations in textbooks, other examples of operational/instrumental approaches are found in these alternate axiomatizations of finite dimensional quantum mechanics:

    http://arxiv.org/abs/quant-ph/0101012
    Quantum Theory From Five Reasonable Axioms
    Lucien Hardy


    http://arxiv.org/abs/1011.6451
    Informational derivation of Quantum Theory
    G. Chiribella, G. M. D'Ariano, P. Perinotti
     
    Last edited: Nov 10, 2014
  4. Nov 10, 2014 #3

    e.bar.goum

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    There are many physicists who don't like the copenhagen interpretation! According to this poll, only 42% of the physicists they poll say their favourite interpretation is copenhagen (see page 8). I think it's only that high because it is what is taught first in undergrad classes.

    Now, as to studying that? Arguing about interpretations of QM is mostly in the realm of philosophy of science. I think it's fair to say that most practising physicists actually subscribe to the "shut up and calculate" interpretation. I can think of a few physicists who study this as their "academic hobby". Sean Carroll has been publishing some stuff on MWI lately, and there are some people publishing about pilot wave stuff.

    I don't know of anyone personally who has done a physics grad degree without an undergrad education in either physics, chemistry or mathematics. I don't know if it can be done! But look at the entrance requirements of your favourite university to be sure.
     
  5. Nov 10, 2014 #4
    I can't address your first question, but I have a few comments regarding some things you bring up in the remainder of your post. The spirit in which physicists attempt to confirm/reject interpretations is by looking for a contradiction with known results (thus rejecting the interpretation) or by making new predictions which can be verified experimentally. You seem to want to reject an interpretation on philosophical grounds. Given your background, you might consider looking for philosophy departments where people are researching the topics you're interested in.

    I don't know how much physics you actually know, but it would be difficult to get into, and do well in, a physics graduate program given just your formal background. But given the right amount of interest and determination you can overcome those barriers. It's up to you. Good luck!
     
  6. Nov 10, 2014 #5

    atyy

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    The poll has 24% on "informational" which the authors comment is Copenhagen-like, which would make 66%. Also, it does not say that those who chose other interpretations are opposed to Copenhagen. Bohmian mechanics is consistent with Copenhagen, and Many-Worlds, if it works must recover Copenhagen and the Born rule for the individual observer in any one world.

    Incidentally, Carroll remains unsure whether MWI works. http://www.preposterousuniverse.com...ion-of-quantum-mechanics-is-probably-correct/
     
  7. Nov 10, 2014 #6

    bhobba

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    There are a few around.

    The three I am most aware of are Ballentine:
    https://www.amazon.com/Quantum-Mechanics-Modern-Development-Edition/dp/9814578584

    It must be said however that his objection to it is based on a misunderstanding. We can chat about it when you reach that chapter in his book.

    And David Wallice:
    http://users.ox.ac.uk/~mert0130/books-emergent.shtml

    Also Griffiths:
    http://quantum.phys.cmu.edu/CQT/index.html

    Griffiths isnt really a major departure from Copenhagen - as explained by Lubos a bit later it just fixes a relatively minor problem - but it is a problem.

    The link provides a good introduction to the issues though and is well worth a read.

    Trouble is you are into heavy math territory

    Here is a reading list to build up to it:
    https://www.amazon.com/Quick-Calculus-Self-Teaching-Guide-Edition/dp/0471827223
    https://www.amazon.com/The-Theoretical-Minimum-Start-Physics/dp/0465075681
    https://www.amazon.com/Quantum-Mechanics-The-Theoretical-Minimum/dp/0465036678

    But, as alluded to before, I have to tell you there is no major issue with Copenhagen (only a few minor things) - its basically just the formalism with the idea the quantum state is a state of knowledge:
    http://motls.blogspot.com.au/2011/05/copenhagen-interpretation-of-quantum.html

    The issue is in Copenhagen QM is a theory about observations that appear in a common-sense classical world. But QM is supposed to explain that world.

    For what its worth I hold to the ignorance ensemble interpretation:
    http://philsci-archive.pitt.edu/5439/1/Decoherence_Essay_arXiv_version.pdf

    Thanks
    Bill
     
    Last edited by a moderator: May 7, 2017
  8. Nov 10, 2014 #7
    e.bar, thanks for the reply! Here is my feeling: that (as you said) most physicists don't even talk about interpretation (on the one hand), but yet there is a sense in which the message that comes from physics is contains the philosophical prejudices (in my view, errors) which underlie the conclusions of the CI, and (and this is the key) implicitly defend those philosophical conclusions on the basis of the authority of their scientific expertise. Thus you can't really be a part of the conversation if you're not a physicist--despite the fact that most physicists are of the "shut up and calculate" type, and usually are not experts in philosophy of science and many don't even care.

    In the poll you referenced, 58% said that the choice of interpretation is a matter of personal philosophical prejudice (question 14). And yet about the randomness of individual quantum events 0% said that there was a "hidden determinism!"

    If this latter result is merely a matter of philosophical prejudice (as the former question suggests), then it certainly could be a philosophical error (as I suggest). But the error leads to a disbelief in determinism--the idea that events have causes--which is not only at the heart of scientific inquiry, but at the heart of the entire Western Intellectual tradition! And since physics is the hardest of the hard sciences, this is (in my view) driving society and the western intellectual tradition in a not-so-great direction.

    Thus my interest in the question. I fear that coming at it from a philosophy-of-science angle may not be the most effective way to join the conversation, because it is really physicists (and not philosophers of science) who are seen as having the authority to pronounce on the proper interpretation of their field.

    Do you know what I mean? Or am I wrong?--are philosophers of science considered authorities on the interpretation of physics?
     
  9. Nov 10, 2014 #8

    e.bar.goum

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    I read Carroll's blog post as being very pro-MWI. I think when talking about interpretations, it's foolish to be declarative on the matter. It's philosophy, not physics.

    Saying that MWI must recover the born rule is true, but that doesn't mean that MWI is not opposed to Copenhagen. They have rather different philosophical groundings - unlike copenhagen, MWI is deterministic, has a real wave-function, doesn't have unique histories or collapsing wavefunctions, or a role for the observer. It is also local, and claims that a universal wave-function exists.

    About the only things they agree on is counter-factual definiteness and hidden variables!
     
  10. Nov 10, 2014 #9

    bhobba

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    That's correct. Copenhagen is basically a minimalist interpretation with its own view of the quantum state as simply something that resides in a theorists head (a state of knowledge) similar to Baysian view of probability:
    http://en.wikipedia.org/wiki/Bayesian_probability

    If you are interested in BM our own Demystifer is really into it.
    https://www.physicsforums.com/members/demystifier.61953/

    Thanks
    Bill
     
    Last edited: Nov 10, 2014
  11. Nov 10, 2014 #10

    e.bar.goum

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    AFAIK de broglie-bohm is the only popular-ish interpretation that has hidden variables, and you'll note that no-one in the poll voted for it. So that's actually completely consistent.

    The Bell Inequalities tell us that there may be no local hidden variables, and most physicists accept this.
     
    Last edited: Nov 10, 2014
  12. Nov 10, 2014 #11

    Nugatory

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    Bell's theorem and the Aspect experiments neither confirm nor deny the Copenhagen interpretation, or any other interpretation for that matter.

    Bell's theorem says that the predictions of quantum mechanics are incompatible with any possible local hidden variable theory. All interpretations make the same predictions, so Bell's theorem favors none of them.
     
  13. Nov 10, 2014 #12

    bhobba

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    Some like David Wallice, who are also formally trained in physics, are. But from posts here I can say for sure some don't really understand it properly - of course some is not all - however its somewhat hit and miss.

    I personally would be a bit wary.

    Thanks
    Bill
     
  14. Nov 10, 2014 #13
    So, if I felt strongly that the CI is (a) based on an error, and (b) a purely philosophical bias--what would be the best way to take part in (and perhaps even contribute to) the discussion--studying philosophy of science, or physics?
     
  15. Nov 10, 2014 #14

    bhobba

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    You should nut out the issues yourself.

    That means understanding the physics.

    I STRONGLY recommend the three books I gave before, the consistent history link, then Ballentine.

    For example philosophers I have discussed this stuff with don't know about the very important Gleason's theorem or that Schroedinger's equation etc really follows from symmetry.

    You must understand the exact axioms its based on and precisely what needs to be explained - unfortunately you need a book like Ballentine to do that.

    Don't get too worried about the advanced math. When going through difficult derivations like you sometimes find in Ballentine it's not important from an understanding viewpoint to follow all the detail - you can come back to it later as your math matures.

    Thanks
    Bill
     
    Last edited: Nov 10, 2014
  16. Nov 10, 2014 #15
  17. Nov 10, 2014 #16
    Bhobba, I see six books that you recommend. What order would you suggest reading them?

    If it matters, I was a math teacher although I haven't take calculus since freshman year in college. I've read most of Popper's work, and 5-6 other books on QM.
     
  18. Nov 10, 2014 #17

    atyy

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    The best way is to stop making your error. Physics is not about your philosophical prejudices, but it's about getting predictions that match observations, which Copenhagen-type/instrumental/operational interpretations do. The problem with Copenhagen-type/instrumental/operational interpretations is not philosophical bias. The problem is called the 'measurement problem'. One description of the measurement problem is found in John Bell's http://www.tau.ac.il/~quantum/Vaidman/IQM/BellAM.pdf.

    For non-relativistic quantum mechanics, Bohmian mechanics and its variants provide one class of solutions. The main problem with Bohmian mechanics is that it is unclear whether it can also describe the relativistic quantum mechanics of the standard model, in particular whether it can describe the interactions of chiral fermions with non-Abelian gauge fields. Bohmian mechanics in general does predict deviations from quantum mechanics, and is in principle falsifiable.

    Another approach to the measurement problem are the Many-Worlds proposals. However, there is at present no consensus on whether these proposals address all technical details. The book by Wallace recommended by bhobba is very good, and really tries to fill in the technical details and discuss the remaining problems. A shorter assessment of the problems of Many-Worlds is given by Sean Carroll at http://www.preposterousuniverse.com...ion-of-quantum-mechanics-is-probably-correct/.
     
  19. Nov 10, 2014 #18

    DrChinese

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    You won't find an "error" in CI in the normal sense of the word, as it has already proven itself useful in many many respects. After all, there is the experimental canon which is extremely deep. More study in science with convince you of that relatively easily.

    You may find philosophical issues you feel are best addressed by other interpretations, however. Study of philosophy might help in that regard.
     
  20. Nov 10, 2014 #19
    Philosophy proper is an area of study in it's own right, quite distinct from physics or any other discipline. And it's not as if one depends on the other, or is a function of the other. Physics can function quite happily on it's own, without philosophy. And vice versa.

    That said a concept in philosophy or physics might very well share some connection or affinity with the other. There can be overlap. And there will be crosstalk, and this might very well provide for further inspiration/elaboration in one, or the other, or both disciplines. Or not as the case may be.

    Between art and physics, for example, there can be quite interesting crosstalk. A science fiction movie, for example, can find inspiration in some aspects of physics. And physics, for it's part, can find inspiration in movies, eg. in what sort of technology might be constructed for the creation of a movie: tools such as a camera, or photographic film, or a CCD chip, or digital projector.

    An artist in residence at a particle collider, might draw inspiration from the marvellous visuals produced in particle collisions, and the mathematics used to transform such visuals (eg. a DFT) and might construct and display a giant collage out of all of this information. But it's not as if a particle accelerator is a tool for producing such artwork. But an artist that understands a collider in just such a way, might very well produce far more interesting work that way.

    The Copenhagen Interpretation. I've always liked this interpretation. It's minimalism. And particularly it's observation-centric approach. It also provides a solution to the communication challenges the early architects of QM faced when introducing the physics for the first time. So it's quite an apt interpretation to use in an introductory course on QM.

    But yes, interpretations will have tendency to end up more as a contribution to philosophy than to physics. But you never really know, following some particular line of interpretation, in which world you might end up.

    C
     
  21. Nov 10, 2014 #20

    bhobba

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    It does because math IS required. But fortunately for you, you simply need a bit of a refresher.

    My order is:
    https://www.amazon.com/Quick-Calculus-Self-Teaching-Guide-Edition/dp/0471827223
    This is to bring your calculus back up to speed

    https://www.amazon.com/The-Theoretical-Minimum-Start-Physics/dp/0465075681
    This is to get a reasonable understanding of the more advanced aspects of mechanics such as Poisson Brackets etc relevant to QM

    https://www.amazon.com/Quantum-Mechanics-The-Theoretical-Minimum/dp/0465036678
    This starts you on QM proper

    The author, Lenny Susskind, also has some associated video lectures:
    http://theoreticalminimum.com/

    Then Griffths, which gives a good introduction to the issues from the Consistent Histories viewpoint:
    http://quantum.phys.cmu.edu/CQT/index.html

    Then, what many such as myself, consider THE book on QM - Ballentine (very strong on the so called ensemble or statistical interpretation - but some small blemishes with misunderstandings of Copenhagen and not going into the important area of decoherence which for some reason he is negative toward):
    https://www.amazon.com/Quantum-Mechanics-Modern-Development-Edition/dp/9814578584

    Then David Wallice:
    http://users.ox.ac.uk/~mert0130/books-emergent.shtml

    After that you will have a VERY good grounding in QM and its interpretive issues.

    Its no easy task you have set yourself. It will take time, perseverance, and patience. But its not a race, take your time and enjoy the journey in full knowledge when you come out the end of it your understanding will be way beyond the, unfortunately, often 'junk' that is peddled in the populist press - not always mind you - but unfortunately often enough to cause those that know the real deal to wince.

    Thanks
    Bill
     
    Last edited by a moderator: May 7, 2017
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