See Chapter 9 of Peres's book, particularly the section called "The consistency problem", p. 376 if I remember right. I suspect you already have what Peres says built into your view so there's no issue with what you call the "Minimal view", but technically it's an issue with textbook QM.vanhees71 said:How can there be a contradiction, since that's how our theories are applied by experimentelists and also the other way around, how models and maybe finally theories are developed from analysis of experiments.
I think Peres's textbook is the most (if not the only) sensible textbook on interpretational issues I know.
I think, pedagogical studies can have there merits but I'm highly suspicious, though I like one type of empirical studies: You teach some topic in different ways to different groups and then look at the outcome of problem-solving sets/exams, including also asking conceptual questions. It's amazing what sometimes comes out from such studies. E.g., there's a recent textbook on school students' (of various grades) as well as university students' understanding of standard physics concepts. In quantum theory even at the university level there are amazing outcomes of such studies: E.g., in one study they found out that after a QM lecture students (5-11 semester at the university) just had the "particle idea of light/photons" but have not associated any wave aspects of light anymore. This is amazing given the fact that in teaching QM usually one starts with empasizing the wave-particle-duality aspect pretty much, but it seems that the "photons as miniature bullets" idea sticks, and for me this confirms that one should from the very beginning emphasize that this old picture a la Einstein is simply wrong and that for a full understanding of photons they have to wait for the QFT lecture.DarMM said:There's very little research on the pedagogy of QM particularly for higher areas like QFT and interpretations. I'd also have opinions on the best way to teach QFT. There's no studies about it, but I do think it for reasons that come from lecturing and talking to other lecturers. I've had a bit about interpretations at the end of my QM lectures. No there is no study, but there aren't really many such studies for any higher area of physics. I have one anecdotal experience as a lecturer, you have another as a moderator here. Yes we can't say more than that since there are no studies, but I don't think that makes my view ridiculous.
I also have strong opinions about some religious questions (for instance I think I can prove that omnipotent God is a logical contradiction) and like you, I also don't argue those positions here. But ...Dale said:In my personal life I have strong philosophical positions to which I am quite firmly attached, e.g. I am a devoutly religious person. I don't argue about those positions at all.
... unlike you, I don't think that something is not philosophy just because it is physics. I think many topics, including quantum foundations, are both. In fact, the very first post in this thread is precisely an argument that it doesn't make sense to make a clear cut between interpretations (that is, philosophy) and theories (that is, physics).Dale said:... the P in PF is physics, not philosophy.
My personal anecdotal experience is precisely the opposite. With some intuitive interpretation in my mind, I find it easier to deal with some practical questions too. For me, interpretations are not definite but mutually exclusive truths, but practical mutually complementary tools. I find it hard to think about practical details if I don't have a big intuitive picture of all this in my mind. My understanding of Bohmian mechanics or many worlds helps me to be a better "Copenhagenian" when it's appropriate. But I guess that's very individual.Dale said:I disagree about the pedagogical value of interpretations arguments. In my personal (anectdotal) case it is definitely an obstacle to learning, not a benefit.
Dale said:I disagree about the pedagogical value of interpretations arguments.
Dale said:Sure. I completely agree with you here. I ask myself many non-scientific questions. I just (a) recognize that they are non-scientific (b) don’t ask them here (c) don’t bother to argue about them at all (d) keep an open mind and (e) switch positions as often as I find convenient.
For me, the biggest problem here on PF is (c). You all argue incessantly and interminably about this stuff. It is all opinion! It may be the opinion that you hold in your heart, but it is just an opinion. Why do you all argue so much about opinions?
Interpretations (beyond the minimal interpretation) have little scientific value, and only this “in your heart” emotional attachment. So please (all of you) tone down the arguments substantially.
This approach I like. If an interpretations discussion took this approach then I could believe it would be pedagogically beneficial. Something along the lines of introducing a particular type of problem, introducing a specific interpretation that is well suited to that type of problem, and allowing that interpretation to guide the solution of the problem.Demystifier said:I find it easier to deal with some practical questions too. For me, interpretations are not definite but mutually exclusive truths, but practical mutually complementary tools. I find it hard to think about practical details if I don't have a big intuitive picture of all this in my mind.
Here is the personal frustration: I would like to know more QM than I do, but I find the interpretations discussions here to be a severe obstacle to doing so. I hate the music you listen to partly because you are playing it so loud and so continuously that it drowns out the music that I want to listen to.dextercioby said:What you just did, metaphorically speaking, is just tell people "I hate the music you listen to", when you have the option to not simply listen to it...
I would but the junk Netflix series was being continuously broadcast on top of Amazon Prime. Unless they fixed it recently.dextercioby said:So you think some Netflix series is junk, wasted money. Then simply turn to HBO or Amazon Prime.
I don’t moderate them, I am not qualified. I am not here as a moderator, just a participant, and only as a participant because the title was “Against Interpretation” so I thought it would be a thread specifically for voicing my kind of opinion.dextercioby said:You have the option to not moderate these borderline physics/philosophy discussions
I'm not sure about whole threads, but posts of that form exist. See e.g. myDale said:This approach I like. If an interpretations discussion took this approach then I could believe it would be pedagogically beneficial. Something along the lines of introducing a particular type of problem, introducing a specific interpretation that is well suited to that type of problem, and allowing that interpretation to guide the solution of the problem.
Do such threads exist here?
Physics has several main problems that many physicists (almost all bloggers) debate. How else would people solve these problems. People here with a spectrum of knowledge strength give their "opinion" , that is part of the process (whether PF or any other place).Dale said:I am hoping that the new Interpretations forum will alleviate this issue in the future. But in the past this has been a problem for me personally.
Anecdotal, yes, but it describes very well the problems I had with my first quantum mechanics class and I've heard similar things from peers. A balanced discussion of the various ideas about what it could mean would have been a very useful guide to thinking. A close second would have been "This is the recipe and we don't know why" as opposed to strong metaphysical positions on indeterminacy, non-realism, etc. I hope that has changed at least.Demystifier said:My personal anecdotal experience is precisely the opposite. With some intuitive interpretation in my mind, I find it easier to deal with some practical questions too. For me, interpretations are not definite but mutually exclusive truths, but practical mutually complementary tools. I find it hard to think about practical details if I don't have a big intuitive picture of all this in my mind. My understanding of Bohmian mechanics or many worlds helps me to be a better "Copenhagenian" when it's appropriate. But I guess that's very individual.
Well, I disagree, even though LL is among the best textbooks I know. The classical description of macroscopic situations, including measurement devices, is an effective description which can be understood from quantum theory by basic statistical arguments (law of large numbers etc.), and then I can use the effective description of the macroscopic measurement device to understand why I measure the observable of the "quantum object" I want to measure. There is no cut but just the applicability of a "classical" description for many-body systems and some appropriate coarse grained macroscopic observables. FAPP of course you can argue with a cut. The observable outcome is the same.atyy said:I hope you at least agree that quantum mechanics in the minimal interpretation requires - different people say this differently - a "classical-quantum" cut or grant the observer or measurement apparatus a special status. After all, this is right at the start of Landau & Lifshitz, one of the most famous textbooks.
Englert's article and the books by Ballentine's and by Peres have something. Englert and Ballentine sweep the problem under the carpet of very soft arguments. Peres admits towards the end of his books (see your post #303) that there is a problem when one applies quantum mechanics to a full model of the measurement problem. I concur with Peres, who (unlike Ballentine, Englert, and @vanhees71) is very precise in his arguments.DarMM said:I have never seen a clear presentation of the measurement problem in the so called "minimal" view. The measurement problem is a logical incoherence in the theory, not just metaphysics. I don't think you can get out of it just by being positivist/empiricist. Or could somebody give me a clear explanation of the measurement problem in the minimal view?
Successful use does not exclude logical deficiencies. It is similar to the foundations of set theory. It had been used very successfully for over 20 years before Russell discovered a contradiction in naive set theory, and it took another 20 years to fix it through axiomatic set theory. Today most people still don't care since they can use naive set theory without problems.vanhees71 said:How can there be a contradiction, since that's how our theories are applied by experimentalists and also the other way around, how models and maybe finally theories are developed from analysis of experiments.
DarMM said:I have never seen a clear presentation of the measurement problem in the so called "minimal" view. The measurement problem is a logical incoherence in the theory, not just metaphysics. I don't think you can get out of it just by being positivist/empiricist. Or could somebody give me a clear explanation of the measurement problem in the minimal view?
DarMM said:If by the minimal view we mean what Peres has in his book that's fine. If we mean textbook QM/what most people mean by "shut up and calculate" then no that does have a contradiction.
To what extent do you think stressing "interpretation" instead of "theory" is a holdover from the logical positivism that gripped some of the founders of quantum mechanics (and their students, and their students, and...)?Demystifier said:
Tim MaudlinLogical positivism is a very attractive view for people who do not want to worry about what they cannot observe. It is ultimately a theory about meaning, about the content of a theory. According to the positivists, a theory says no more than its observable consequences.
Logical positivism has been killed many times over by philosophers. But no matter how many stakes are driven through its heart, it arises unbidden in the minds of scientists. For if the content of a theory goes beyond what you can observe, then you can never, in principle, be sure that any theory is right. And that means there can be interminable arguments about which theory is right that cannot be settled by observation.
It has no problems if one considers (as you do) Born's rule to be just an axiom without asking further what a measurement is on the level of theory. But the measurement problem appears once you want to give the notion of measurement a mathematical meaning (and only then Quantum mechanics including Born's rule is a mathematical theory).vanhees71 said:I still don't understand your argument. Of course, the issues with set theory were mathematical issues and had to be resolved to have a solid foundation of set theory and given its importance as a basic tool in all branches of mathematics also of mathematics as a whole.
Quantum mechanics, at least the non-relativistic flavor, has no mathematical problems as far as I can see. This of course includes Born's rule
There are no foundational problems at the level where QM is actually applied - namely in the microscopic domain. There are foundational problems if one wants to extend QM to the macroscopic regime and still stay faithful to its textbook foundations.vanhees71 said:As a physical theory QM is amazingly successful, and there are no foundational problems.
You gave this statement your Like - so you can probably explain why Peres wrote Chapter 12 of his book, titled ''The measurement problem'' if the latter does not exist. Peres deliberately and faithfully follows the minimal interpretation dogma that you also advocate until he reveals that he has to give it up in this chapter:atyy said:I think the minimal view is what Peres has (maybe Peres has very minor errors, but I think his book is beautifully written), and that should be the same as shut-up-and-calculate. Any minimal view that is not like what Peres has is just not properly informed by tradition.
Asher Peres (p.377) said:There are questions, such as “what is the numerical value of the pointer position,” which make sense in the classical language, but are meaningless in the quantum language.
Asher Peres (p.424) said:This would cause no conceptual difficulty with quantum theory if the Moon, the planets, the interstellar atoms, etc., had a well defined state ρ. However, I have insisted throughout this book that ρ is not a property of an individual system, but represents the procedure for preparing an ensemble of such systems. How shall we describe situations that have no preparer?
The dogmatic part is mathematical physics and has unsolved consistency problems in which people like me or DarMM are interested. The pragmatic way out is FAPP only but satisfies those like you who don't care about mathematical consistency of theoretical physics as long as the predictions are successful.Asher Peres (p.424) said:You must have noted the difference between the present pragmatic approach and the dogmas held in the early chapters of this book. It was then asserted that any operator which can be written by a theorist can also be measured in the laboratory. This fiction was needed in order to establish a formal framework for quantum theory.
Yes. But this is where the mathematics of quantum physics has a consistency problem when it tries to model the whole experiment in terms of a microscopic description. You say you don't care because its established by experience. Others like me care because its not established by the theory.vanhees71 said:I don't think one has to explain that there are clearly defined pointer readings in an experiment, because that's one of the assumptions you make as a theoretical physicist because that's established by experience.
Clearly there is no way we can agree. But perhaps you can at least understand why others, including me, consider the measurement problem as something real.vanhees71 said:I still don't understand your argument.
To a great extent. Let me also add that logical positivism is self-contradictory. That's because the main claims of logical positivism (e.g. that "only the measurable has a meaning") are themselves philosophical claims not obtained from measurements. What logical positivists really say is: "All philosophy is meaningless, except our philosophy."Minnesota Joe said:To what extent do you think stressing "interpretation" instead of "theory" is a holdover from the logical positivism that gripped some of the founders of quantum mechanics (and their students, and their students, and...)?
Yes it is infamously self-defeating and you would have to special plead to hold it. As Maudlin points out, you still encounter the attitude in the sciences however.Demystifier said:To a great extent. Let me also add that logical positivism is self-contradictory. That's because the main claims of logical positivism (e.g. that "only the measurable has a meaning") are themselves philosophical claims not obtained from measurements. What logical positivists really say is: "All philosophy is meaningless, except our philosophy."
Is it "due" to or inherently, because that is how the electron in hydrogen atom is modeled?vanhees71 said:The fact that in QM a particle has precisely the probabilistic properties due to its preparation, described by the corresponding quantum state ^ρρ^\hat{\rho} is
In the age of gravity wave detection experiments isn't possible to do the same for quantum. I mean couldn't they use a thin sheet of single carbon or whatever atom and have some miniature source using femto cameras and such. Money should be no problem, right?vanhees71 said:That measurement devices, as macroscopic objects, behave classical is also no surprise but just due to sufficient course graining of the macroscopic observables. A "pointer position" of a measurement device is such a coarse-grained macroscopic observable.