Talk:Interpretations of quantum mechanics/Archive 4

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dubious?

Is it dubious that Dirac wrote this, or dubious that he thought it was an interpretational question? The entry in the article clearly avoids an opinion about the validity of Dirac's view.Chjoaygame (talk) 10:26, 14 September 2014 (UTC)

That is just the problem. The idea that "Each photon then interferes only with itself. Interference between two different photons never occurs." is clearly wrong. Two photons (in the same state) are indistinguishable, so it is not even meaningful to ask whether one at a later time is the same individual photon as one at an earlier time. Dirac may have said it, but leaving its correctness open is misleading regarding current understanding. It is not an open question in physics. JRSpriggs (talk) 01:11, 15 September 2014 (UTC)

Thank you for this thoughtful comment. I think Dirac is referring to an actually detected detected photon. An actual detection is a unique event. It ends the life of the detected photon, which cannot be re-examined. The entry intends to raise the question, not to answer it. The idea that two photons in the same state is itself, I respectfully suggest, an interpretation of the formulas. Perhaps an infallibly correct interpretation, but still an interpretation. I think Dirac's sentences do raise interpretational questions, indeed important interpretational questions. The question of what they mean is an interpretational question, on which you have an opinion, right enough, but still an interpretational opinion. You say that your view is "current understanding"; that makes it interpretational. I will try to think of a way to re-word the entry to meet your concern.Chjoaygame (talk) 03:22, 15 September 2014 (UTC)

If Dirac was writing before the 1960s he was referring to incoherent light. With incoherent light each photon is in a separate quantum state, so of course each photon "can only interfere with itself". That was the only type of interference possible in double-slit experiments before lasers were invented in the 1960s. Incoherent light interference is equivalent to modern single-photon experiments, in which the intensity of the light is reduced to the point where a single photon is in the apparatus at a time. --Chetvorno^TALK 04:24, 15 September 2014 (UTC)

I was quoting the fourth edition, 1958. Low intensity does not entirely do the trick. The best way is with herald experiments, nowadays possible. I have nevertheless tried to comply with the concern about meaninglessness.Chjoaygame (talk) 04:35, 15 September 2014 (UTC)

Footnotes and references

I think it would be better to have footnotes (e.g. #2) separated from references (e.g. #1, 3, & 4). Bubba73 ^{You talkin' to me?} 00:28, 28 September 2014 (UTC)

undid good faith edit

I undid a good faith edit, for the following reasons.

1. The edit, even if it were admissible on other grounds, was, on its merits, inappropriately placed. It announces itself as new. Therefore it cannot be an established interpretation; at best it would be a minority interpretation, properly placed in the article Minority interpretations of quantum mechanics. The undone edit references only what is evidently a single basic source, perhaps the editor who posted it. An established interpretation would be supported by a fair number of more or less mutually independent secondary reliable sources.
2. Sourcing itself from a single-issue new username, the undone edit was evidently promotion by an author of new research, and thus presumably self-interested, that is to say, subject to conflict of interest, not from a neutral editor. Wikipedia edits of this kind are regarded as soap-boxing.
3. The undone edit was original research, probably by its author or a related person. Wikipedia does not post such original research, even if it has some refereed published source.

Obviously the edit was in good faith, but that is not sufficient for it to stand in the article. It is unfortunate for the undone edit that, regardless of the merits or demerits of its content, it is, by Wikipedia editing rules, formally inadmissible.Chjoaygame (talk) 02:26, 19 October 2014 (UTC)Chjoaygame (talk) 03:01, 19 October 2014 (UTC)

Yep, doesn't belong. Great work, Second Quantization (talk) 22:20, 27 October 2014 (UTC)

Perhaps somewhere we should explain that an added interpretation should (1) be published in a reputable journal, and (2) be recognized by neutral sources as one of the significant interpretations. Roger (talk) 05:45, 28 October 2014 (UTC)

It needs to be supported by reliable sources, and should not breach any Wikipedia policy. That's it.

I would say it is risky to over-explicitly try to spell out Wikipedia policy on the run, more or less ad hoc, for example by talking about reputable journals. For particular cases, exactly what is a reliable source, and exactly what is Wikipedia policy, is ultimately a matter of editorial judgement and skill.Chjoaygame (talk)

deletion of "no interpretation needed" and related

It is already claimed by the principal authority on the "Copenhagen interpretation", Werner Heisenberg, that the Copenhagen interpretation is not really an interpretation, but is the only right way to see things. The Fuchs and Peres article and its dependents do no more than repeat that view that was expressed by Heisenberg in relation to his virtual original formulation of the Copenhagen interpretation. It is not useful at this point of the article to have such virtual repetition of what is of dubious notability. Therefore I have deleted the sentences about it, that read "A strictly formalist position declares that interpretation is unnecessary and misleading, and that no experiment can distinguish the interpretations.<Quantum Theory Needs No ‘Interpretation’, Christopher A. Fuchs and Asher Peres, Physics Today, 2000, [1]> This has been challenged by proposals for falsifiable experiments that might one day distinguish among interpretations, as by measuring an AI consciousness<Quantum theory as a universal physical theory, by David Deutsch, International Journal of Theoretical Physics, Vol 24 #1 (1985)> or via quantum computing.<Three connections between Everett's interpretation and experiment Quantum Concepts of Space and Time, by David Deutsch, Oxford University Press (1986)>"Chjoaygame (talk) 00:05, 24 December 2014 (UTC)

I disagree. You say it duplicates Heisenberg, but that Heisenberg opinion is not in the article. The opinion should be there somewhere, as it is at least as important as Deutsch's opinion. Roger (talk) 02:28, 24 December 2014 (UTC)

Thank you for your comment. I agree that more detail could be put in here, but should be judiciously chosen. I feel that what I deleted gave it undue prominence. Please give me a little time to think about it.Chjoaygame (talk) 02:47, 24 December 2014 (UTC)

Perhaps you will very kindly expand on how Deutsch's opinion comes into it.Chjoaygame (talk) 03:11, 24 December 2014 (UTC)

Digging a little, I see that the original remark about not needing an interpretation was in the nature of editorial comment introducing material by Deutsch. As I see it, Deutsch was not specifically targeting and seeking to refute the no-interpretation-needed thesis. As I see it, Deutsch was just putting his own viewpoint, which happens to refer to the many-worlds interpretation.Chjoaygame (talk) 06:15, 24 December 2014 (UTC)

Digging further, I see that the no-interpretation-needed thesis is a sort of relic or shard of earlier poorly sourced comments on the instrumentalist interpretation.Chjoaygame (talk) 06:29, 24 December 2014 (UTC)

The Deutsch material was added here. I think the Deutsch material may be interesting in some context, but that it is not appropriate in this particular section on the history of interpretations of quantum mechanics. Deutsch was not advancing a new interpretation so much as referring to older ones.

There is a good case for restoring here some version of the earlier accounts of the instrumentalist view. This does not mean that the Fuchs Peres article is the one to cite.

It verges on nonsense to say that "no" interpretation is needed. Fuchs and Peres were playing with words. As for Heisenberg's view, a careful reader would already have encountered it by following the link Copenhagen interpretation.Chjoaygame (talk) 07:01, 24 December 2014 (UTC)

This article has a multitude of mainstream views. To some people, Copenhagen is pretty much the same as the instrumentalist interpretation, and that is pretty much the same as no interpretation at all. Fuchs has gone on to promote Quantum Bayesianism, which again is not much different. Maybe these could be lumped together. Regardless, it is important to say that while some people view the choice of interpretation as very important, others do not. The article has the "Shut up and calculate" quote, which seems to be another attempt to eschew interpretations. Roger (talk) 07:21, 24 December 2014 (UTC)

I think that the historical section, at least at its present state of development, is not the place to try to list the interpretations or to criticize or debate them.

If a section about popularity is considered useful, it could well be written.

I cannot quite agree that the Copenhagen interpretation is pretty much the same as no interpretation. It is in fact very hard to work out from pure logic or first principles exactly what the mathematical formalism means in physical terms, unless one has a built-in uncritical preconception and cannot see the difficulties. If one feels one already knows the one and only correct interpretation, then of course one finds it easy to say "Oh, the mathematical formalism unequivocally means such-and-such, and no interpretation is needed."

Heisenberg thinks his interpretation is the only reasonable one, and he called it the Copenhagen interpretation, though he later said he wished he hadn't. He doesn't say that no interpretation is needed. He says that those other than his are nonsense.

The body of the article has a section entitled Interpretations of quantum mechanics#Summary of common interpretations of quantum mechanics#Instrumentalist interpretation. There is a link to the Wikipedia article Instrumentalist interpretation. The latter article has no references, and is a free-running editorial essay. I don't recommend us linking this article to it. If you are seriously interested in this, Gunther Ludwig's Foundations of Quantum Mechanics ISBN 0-387-11683-4 might perhaps be a good place to look.

If you feel that the history section needs to record that some writers think interpretation is unnecessary or unimportant, you could put it in. I think that the Fuchs and Peres article would not be a suitable source for such historical information. In my reading of it, that article is an attempt to present an interpretation. It is headed in the journal as 'Opinion', I think rightly so. I will not here spend time analyzing it. It pretty much falls under the class that I adumbrated above, of writings by authors who feel they already know the one and only correct interpretation, so that they find it easy to say "Oh, the mathematical formalism unequivocally means such-and-such, and no interpretation is needed." They are of course entitled to feel whatever and however they like. But that doesn't make them reliable sources about history.Chjoaygame (talk) 11:03, 24 December 2014 (UTC)Chjoaygame (talk) 11:31, 24 December 2014 (UTC)

Why are you deleting good material? If you think it is in the wrong section, just move it. If you are just applying your personal opinion about interpretations, then please allow this article to reflect the mainstream views of others. Roger (talk) 17:34, 24 December 2014 (UTC)

You did well to draw attention to the faulty character of the material that I have deleted. The faults arose, as indicated by you, through lack of reliable sourcing. The prime problem is lack of reliable sourcing about the extreme minimalist views, such as for example the view that no interpretation is needed. Nearer the mainstream, there is lack of reliable sourcing about the instrumentalist view. The article has a section about the instrumentalist position, and it sadly lacks adequate sourcing. The lack of sourcing led to a distorted over-emphasis or misplacement of that view in the history section, and to the inappropriate placing of other opinion in that section. It is not enough that material have some source, such as an opinion piece in a newsletter such as Physics Today. Entries should be sourced from adequate investigation of the literature with special attention to reliability, and notable in the context in which they appear. A duty of Wikipedia editors is judicious selection of material to provide balanced emphasis.

It damages Wikipedia to litter it with poorly sourced and inappropriately placed or emphasized material. Sad to say, years of creeping and careless inattention to sourcing and to notability in context had led to misleading placement of poor quality material. In a nutshell, the Fuchs & Peres material was poorly sourced opinion and the Deutsch material was not notable in context. Their initial posting was wrong; it is unfortunate that its due undoing has been long delayed. That is why I deleted them.

You did well in moving some minority material to the minority interpretations article.Chjoaygame (talk) 23:32, 24 December 2014 (UTC)Chjoaygame (talk) 09:38, 25 December 2014 (UTC)

Perhaps superfluously, I have chased up the previously carelessly posted and over-emphasised Deutsch reference to its accurate source and posted the latter in a more or less appropriate place.Chjoaygame (talk) 00:04, 25 December 2014 (UTC)

I fear that you are injecting your own opinions. There are a couple of mainstream physicist views. One says that the lack of a consensus on interpreting quantum mechanics is a huge problem, and that we need a lot of research and debate on the merits of pilot waves, many-worlds, etc. The other view is that Copenhagen or some instrumentalist variant is just fine, and all this talk of interpretations is a big waste of time. The article should reflect both views, regardless of your opinion or my opinion. Roger (talk) 01:04, 25 December 2014 (UTC)

The article well reflects the range of views. The present question is as to presentation. I see the article as a whole as needed for the task. I think it not good to try to squeeze a second, summary, version into the history section. The two that you list in your just immediately above comment are far from an adequate summary.

I have now put your reference to Fuchs & Peres (2000) into a suitable place in the article.Chjoaygame (talk) 03:58, 25 December 2014 (UTC)

MIW

Please, add Many-Interacting-Worlds interpretation: http://arxiv.org/abs/1402.6144 http://journals.aps.org/prx/abstract/10.1103/PhysRevX.4.041013 http://www.newscientist.com/article/mg22429944.000-ghost-universes-kill-schrodingers-quantum-cat.html http://www.nature.com/news/a-quantum-world-arising-from-many-ordinary-ones-1.16213 90.154.68.242 (talk) 15:17, 16 February 2015 (UTC)alex

I don't know exactly what qualifies for a mention in Minority interpretations of quantum mechanics, and so I don't have an immediate opinion about whether this one should be posted there. But I feel sure it should not be posted in the present article here.Chjoaygame (talk) 16:24, 16 February 2015 (UTC)

There is Many-worlds interpretation in this article. Why not add similar but distinctive Many-Interacting-Worlds ? 90.154.68.242 (talk) 16:34, 23 February 2015 (UTC)alex

Because MIW is just a proposal without any following. The secondary literature on the major interpretations does not mention it. I suggest putting it in the Minority article. If it gains traction, it can be promoted to this. Roger (talk) 17:46, 23 February 2015 (UTC)

Non-locality in Copenhagen Interpretation

In the comparison chart it says Copenhagen is non-local. This contradicts the Wikipedia article on the Copenhagen Interpretation. It is also dubious because Copenhagen is the standard model, and non-locality contradicts the generally accepted theory of general relativity. As per Wikipedia's rules, to ensure that all Wikipedia content is verifiable, anyone may question an un-cited claim by inserting a tag, and I have done so. — Preceding unsigned comment added by 153.203.90.130 (talk • contribs) 23:56, 8 March 2015‎ (UTC)

How do you see the contradiction? I see nowhere in Copenhagen Interpretation claiming locality – only contrary claims (i.e. of non-locality) are mentioned in the article. —Quondum 00:45, 9 March 2015 (UTC)

The article distinguishes between the Copenhagen and von Neumann interpretations. Not everyone does. I think it is fair to say that the vN is non-local, but there is an argument that Copenhagen is local. Roger (talk) 01:52, 9 March 2015 (UTC)

You'd have to be clearer about which part of the the article asserts that it is local for people such as me who fail to see this. We have a claim that there is a contradiction on the matter of locality with that article that is not clearly apparent, at least to me. —Quondum 02:11, 9 March 2015 (UTC)

The Copenhagen Interpretation article does say: "However, proponents of many worlds[43] and the transactional interpretation[44][45] (TI) maintain that Copenhagen interpretation is fatally non-local." Well, yes, the main argument for those other interpretations is that there is something fatal about Copenhagen. But those people are really complaining about the vN interpretation. It also says "displayed non-locality is not at odds with special relativity." Special relativity requires locality, so that means that there appears to be a non-locality, but it not really non-local. Roger (talk) 03:36, 9 March 2015 (UTC)

You don't seem to be pointing out the contradiction referred to, only making an interpretive argument (by saying that the phrase "Copenhagen interpretation" really means something other than the Copenhagen interpretation – go figure) that the article is not saying that it is non-local. Which is an argument that the article is saying nothing on the topic, not that there is a contradiction. So the argument misses actually being valid in two counts, as I see it. Anyhow, the distinction between the von Neumann and Heisenberg perspectives, judging from the article, is only the distinction between "collapse" and "reduction". I don't see how this makes any difference to locality; any change to the wavefunction gives rise to the problem of nonlocality. —Quondum 04:06, 9 March 2015 (UTC)

Since much of this relates closely to the article Copenhagen interpretation, I have made some comments on the question on the talk page of that article.Chjoaygame (talk) 00:45, 10 March 2015 (UTC)

There is some ambiguity here over nonlocality. The Copenhagen interpretations insists there are nonlocal correlations that are classically forbidden, but it does not insist these correlations are due to nonlocal action. The stronger correlations of QM are permitted due to the representation of observables as Hermitian operators, but the CI is not committed to any deeper explanation of this correlation HiMyNameIsKelso (talk) 15:40, 16 March 2015 (UTC)

"Collapsing Wavefunctions?" is ambiguous

Does collapsing wavefunction in the table mean physical collapse, or does it also include the unphysical process of an observer updating their knowledge? The Copenhagen interpretation, as it is usually described, does not consider the wavefunction to be real, so collapse is unphysical, just as it is unphysical in the ensemble and consistent histories interpretation. This is in contrast to, say, objective collapse theories. Yet the table implies the Copenhagen interpretation has more in common with objective collapse theories than it does with the ensemble or consistent histories interpretation in this regard. If "Collapsing Wavefunction" includes unphysical acquisition of knowledge, then the Copenhagen interpretation posits collapse, but so does the ensemble and (arguably) consistent histories interpretations HiMyNameIsKelso (talk) 16:10, 16 March 2015 (UTC)

The collapse (when doing a measurement) occurs whether a person pays attention to the result or not. So collapse can occur even if no knowledge is obtained. From the standpoint of non-collapse interpretations, this is due to the measurement entangling the state of the system with rest of the universe (i.e. with a heat sink). That is, the phase of the non-system is changed by an amount which depends (randomly) on the eigenvalue of the measured observable. JRSpriggs (talk) 01:18, 17 March 2015 (UTC)

My understanding is there's a difference between collapse and decoherence. Decoherence lets us assign classical probabilities to possible outcomes, but "collapse" is the actualisation of just one possibility. Perhaps, instead of "Yes" and "No", we should use "objective" and "subjective". The ensemble, consistent histories, and Many-worlds all consider collapse to be subjective, while Von Neumann, transactional, and objective collapse all posit objective collapse (Copenhagen is subjective, or at least agnostic). HiMyNameIsKelso (talk) 15:35, 17 March 2015 (UTC)

The terms 'objective' and 'subjective' are primarily philosophico-psychological. I think that use of them in the present context leads more to confusion than to enlightenment or clarity. I think it is better to avoid them.Chjoaygame (talk) 18:31, 17 March 2015 (UTC)

new logical structure needs revision

There is a bundle of new edits. One feature of them is that they are largely built around the validity or invalidity of the notion of collapse or reduction. This in effect dictates a large effect on the logical structure of the article.

I think this puts too much emphasis on the collapse idea. In particular, it results in the so-called 'ensemble interpretation' being described in a format that gives it pre-eminence. I think this is not good. I think that the Copenhagen interpretation should appear pre-eminent. I suppose the editor who made these edits thinks that the article should have a logical structure, and that he thinks that 'collapse' is the key idea and so should dictate the logical structure. In a sense, the so-called 'ensemble interpretation' is agnostic about collapse, and so by its agnosticism, under this scheme it gets to be pre-eminent. A reader might easily assume that the format indicated conceptual pre-eminence. I think that is not good.

Niels Bohr was an important contributor to the Copenhagen interpretation. So far as I know, he said little or nothing about 'collapse'. Heisenberg thought that reduction was an obviously reasonable view, but he did not, so far as I recall, set out a simple formulation of why it is reasonable. It is, of course, obviously reasonable. The beam starts as a pure beam, with one wave function. By the quantum analyzers of the experimental set-up, the original beam is fractionated into sub-beams. Each sub-beam can be considered as pure with respect to the analyzers of the experimental set-up that produced it, with a new wave function. 'Collapse' is the word used to refer to the fact that a fractional sub-beam with its specific wave function, is only fractionally as intense as the original starting beam, with its differing specific wave function. Of course, if, instead of destructive detection, the sub-beams were to be directed together, through reverse copies of the analyzers, so as to re-form that original beam, with its original wave function, 'collapse' would not occur. The real puzzle is not why there is collapse, given that the analyzers do their thing. The real puzzle is why or how the analyzers do their thing. It was John von Neumann who invented the colourful and dramatic term collapse, but he is not a primary source for the Copenhagen interpretation. So it is misleading to try to characterize, as do the new edits, the Copenhagen interpretation as a 'collapse interpretation', especially as it results here in an appearance that the so-called 'ensemble interpretation' is pre-eminent.

Reading Dirac, it is quite clear that he utterly and profoundly rejects the so-called 'ensemble interpretation'. As Dirac explains things, it is almost absurd to try to present quantum mechanics as an "ensemble" theory. I think on this point Dirac is right. Most of the problem is that people don't clearly say what is meant by the word 'ensemble' in this context. I will not try to do it here, but the reader is invited to think it out for himself. On careful reading of his famous last response to critics, I don't think Einstein was clear about the use of the word 'ensemble', and I think he did not accept the so-called 'ensemble interpretation'. So there is muddle in the use of the term.

In summary, I think the logical structure of the new editing needs major revision, to accord with the above criticism. Perhaps the editor who made the new edits will do it.Chjoaygame (talk) 12:43, 18 April 2015 (UTC)

I was going to comment on this once I was done, but you beat me to it.

My edits are guided by the grouping of interpretations in secondary (or tertiary) sources, notably Stanford Encyclopedia of Philosophy and "This Poll". arXiv:1301.1069. doi:10.1016/j.shpsb.2013.04.004. {{cite journal}}: Cite journal requires |journal= (help)

It seems clear to me that this page should group "interpretation" into classes following these (and similar) references. Since interpretations develop organically, and are not really "countable", such a hierarchic approach is almost inevitable.

But it may well be that I have made mistakes or bad choices in the details. Both SEP and the poll recognize as major classes of interpretations (question 12 in the poll)

• Copenagen / collapse theories
• Everrettian / many worlds
• Bohmian / hidden variables
• Modal
• Relational

Of these, the first three categories seem reasonably clear-cut, and also to represent the most important interpretations from a :contemporary perspective.

We have surprisingly little coverage on "Modal" stuff, and confusing or misleading coverage on "Relational". Also, how closely are "relational" approaches related to "information theoretical" or "Bayesian" ones?

The poll further has the following categories:

• objective collapse (e.g. Penrose, GRW) [subsumed under "collapse theories" by SEP]
• Information-based/information-theoretical
• Quantum Bayesianism [part of 'information theoretical']
• consistent histories
• Ensemble
• Transactional

but it admits that they may be overlapping, e.g. QBism is clearly "information-theoretical" (as is, afacis, the relational interpretation?)

So, by all means, my attempt at structuring what was basically a heap of disparate ideas of widely diverging notability should be improved upon, but I do think the grouping into classes should be kept.

Regarding your specific concerns,

• I first gave the so-called 'ensemble interpretation' prominence not because it is widely held but because of its historical primacy (it is the view of Einstein). But since almost nobody bothers with it these days, I then moved it under "other". In any case, I have no desire to argue about the "ensemble interpretation". It seems to be of great interest when studying the history of the question, but of very little interest when studying the main alternatives discussed today. I do think its dedicated article is a mess, and should be cleaned up before we worry too much about what to do with it on this page.

• "Collapse theories" seems to be a major category introduced now (i.e. since the 2000s), as "many-worlds" and "hidden variables" made a come-back from "unorthodoxy". Collapse may not have been the central aspect of the "Copenhagen interpretations" in its heyday, but it is now seen as its major and most problematic aspect by its Everettian or Bohmian detractors. I think the modern or "interpretation-independent" way of talking about "reduction" is decoherence. Still, there is no way around the fact that the Copenhagen interpretation does not have any explicit way of dealing with the measurement problem intrinsically, measurement is something that happens outside or in addition to quantum mechanics "proper". This is what is meant by "collapse", whether you embrace the term or not, and the major alternatives to Copenhagen, i.e. hidden variables or many-worlds are motivated a dislike of exactly this way of "externalising" the concept of measurement.

At least this is the impression I get from the "tertiary" summaries I cited, I am not an expert. Also, I have no stakes in the question (I am pretty agnostic on which interpretation is best, although I admit I find some more jarring than others, but I have not studied them closely enough to be sure this impression would persist if I really understood the suggestions in their details)

--dab (𒁳) 13:56, 18 April 2015 (UTC)

Thank you for these thoughts. I have taken the liberty of putting in the customary indentation format. I hope you will be happy with that.

As I think it over, I am inclined to think it better to avoid trying to structure the presentation as if one had a rational basis for classifying the interpretations. Having spent some time working on sources for Wikipedia articles on physics, I have come to the conclusion that it is very difficult to be sure that a source is reliable. I don't like the idea of trusting the Stanford Encyclopedia too far. It is customary to say that Einstein was a 'supporter of the ensemble interpretation', and in the past I have believed that customary story, but now I think the meanings of the words are very poorly specified, and I don't think Einstein was such a supporter; I think there is a serious problem of definition and semantics that makes it doubtful or unlikely. Therefore I would look very critically at purported sources. It is not enough to find a source. One must find concurrence of reliable sources. A lot of reading is needed.

It does not make sense to say that the so-called 'ensemble interpretation' has "historical primacy" because it is the view of Einstein. The Copenhagen interpretation has historical primacy, at least in so far as it is even well-defined.

Of course it is nonsense to speak of an "interpretation-independent" way of talking about reduction. That would be like speaking of a water-free way of talking about wetness. Likewise of course it is nonsense to pretend that interpretation can be avoided if the article purports to be about physics. The formulas are just formulas. The physical facts are really existent aspects of experience. Physics is about their relations, that is to say, physics is interpretation. A main problem is that writers think that logic can find answers without needing underlying physical understanding, which they don't try to work from.

Perhaps I should stop here. I repeat, however, my view that it it dangerous or pretentious to try to present the interpretations as if one had a rational classification. Most "interpretations" are half-baked muddles. Some important or widely cited ones (which I dare not name) are lunatic. Much talk about collapse demonstrates mostly that the talker is no good at thinking about such matters. An attempt to classify the deviant interpretations can hardly avoid being itself an interpretation not labeled as such. Born describes his view as a statistical interpretation. Often enough the ensemble interpretation is called the statistical interpretation. But Born does not support the ensemble interpretation.

You say that the article on the ensemble interpretation is a mess that should be fixed before much is written about it on this page. Perhaps you are the person to master the sources and do the fixing.

I think you would do better spend time getting a clearer picture of the subject in your own mind than to try to present the subject by cherry-picking from sources. Once an article gets a bad logical structure, it is very difficult to repair it. I think you should climb back from your present excessively rationalistic structuring of your work.Chjoaygame (talk) 16:35, 18 April 2015 (UTC)

instrumentalist interpretation

The article now gives pre-eminence to an interpretation that the article labels "Instrumentalist description". Reading the description I see that it refers to the primary interpretation proposed by Max Born, and subsequently very widely accepted. The presentation might give the impression that somehow the "instrumentalist description" is not an interpretation but is somehow more absolute, somehow "bare" of interpretation. The description says, apparently believing it, that "By abuse of language, a bare instrumentalist description could be referred to as an interpretation, although this usage is somewhat misleading since instrumentalism does not attempt to assign physical meanings to particular mathematical objects of the theory."

Instrumentalism assigns the meaning of probability to the quantities derived from the wave function. Probability is how the physical observations are analyzed. That is the key interpretation proposed by Max Born.

The description uses terms such as "state preparation processes", "measurement processes", and "initial conditions". These are very much interpretative in nature, and the subject of much discussion. They assign physical meanings to particular mathematical objects of the theory, such as for example wave functions.

Some writers regard Bohr as "instrumentalist", but he is almost by definition "Copenhagenist".

In effect, the so-called "ensemble interpretation" claims to be instrumentalist because it claims its assumptions are minimal, which is the claim of "instrumentalists".

The "instrumentalist" interpretation would deceive itself if it imagined that it is not an interpretation. Such a self-deception would work on the principle "What I think is fact, and infallible, while what you think is opinion, and fallible." No, sorry, what the "instrumentalist" thinks is opinion too. Very good opinion, no doubt, but still opinion.

"Instrumentalism" is a claim to some kind of superiority on the claimed ground of some kind of logical parsimony, but really it is just a claim to superiority that can avoid the ordinary requirements of scientific justifying argument.

I am not now editing to correct that error, but am leaving it to the current very active editor to put the instrumentalist view in a more proper place in the article.Chjoaygame (talk) 08:13, 19 April 2015 (UTC)Chjoaygame (talk) 12:05, 19 April 2015 (UTC)Chjoaygame (talk) 23:18, 19 April 2015 (UTC)

Table entry for time-symetric theories

The table entry for time-symmetric theories now cites two (Since I added Costa de Beauregard's one). But Costa de Beauregard's theory was an ignorance interpretation - that is, the wave-function is not regarded as real, but merely as describing the state of our (incomplete) knowledge. The problem is that the table rows are sometimes individual theories and sometimes classes or groups of similar theories. The group of time-symetric theories should probably be split into two lines, one with wave-function real as "yes"/green (as now), and a new one with it "no"/pink. And likewise for the universal wave-function column at the end. My editing skills are not up to that, however. I hope someone else can split the line in two, please. Huw Price's 1996 book "Times Arrow and Archimedes point" (OUP) can serve as a source for this if need be - but his talk at https://www.youtube.com/watch?v=rK4Dq8Wwsd8 is much clearer, in my view. The video, but not the book, calls Costa de Beauregard's interpretation the "Paris Interpretation". Nimrod54 (talk) 00:52, 26 April 2015 (UTC)

From what I recall of my last reading of work by Huw Price, I would be very hesitant to accept anything he wrote as a reliable source for Wikipedia. I think at least some other reliable source would be needed. A source, to be reliable, needs more than that it has been published and quoted by others. For reliability, a source should preferably be in accord with other reliable sources on the question of interest. Circular? Yes, but reliability is hard to prove. Reasonable literature survey is the only way I know.Chjoaygame (talk) 03:35, 27 April 2015 (UTC)

undid faulty edit; reasons

I undid a couple of faulty edits of which this was the second.

The reasons are that the edit was to the wrong article, in the wrong place if it had been suitable for this article, that it is fringe material, original research, that it violates the rule against self-promotion with conflict of interest, and that in editorial format it is very defective.

Dear IP 172.6.65.122 editor, it is good that you make some comment here on your talk page. But you need to know that Wikipedia does not seek to be a newspaper telling of the latest research. The other article you refer to, Firewall (physics), should probably also be deleted because of lack of reliable sourcing by Wikipedia criteria, but at present I do not have time to pursue that matter.

Wikipedia has rules against original research and against self-promotion, both of which your edit seeks to violate. The proper thing for you to do is wait until your research has found its way, or not, into what Wikipedia editors regard as reliable sources. Further, this is at present a content matter, and there is no "upper administrator" who can intervene directly on that at this stage. Anyone who let his student refer to Wikipedia as a research source would be making a big mistake, and that will probably never change. The other complaints that you make on your talk page indicate that you have a lot to learn about the Wikipedia process.

I could go on with more reasons why I undid your edit, but I think the above should be enough for the present.Chjoaygame (talk) 04:00, 15 May 2015 (UTC)

I have offered to send the reearch to editing parties as long as I can verify that you are not a party that is on a US government watchlist, as this is military funded research. I give you the same offer. I am not a ikipedia author, I am a reseacher, soldier, and scientist. It seems philosophically wrong to reject informational articles based on formatting or procedural issues and not with the logic or math of the theorem itself. Please provide an actual scientific argument for rejection instead of a social media taunt.Derenek (talk) 13:59, 11 June 2015 (UTC)

inappropriate entry; reasons

I undid an inappropriate entry for the following reasons.

The article is about mainstream widely considered interpretations. The entry was not about one of those, and was consequently off-topic.

The entry did not have support in Wikipedia-reliable sources.

Wikipedia editors are not judges of merit of new research. It is not the duty of Wikipedia editors to find support for inadequately supported entries of new research. The criterion of fitness for a Wikipedia entry is that the work should have been considered sound by a concordance of reliable sources. Editors need some knowledge and experience, and perhaps some consensus, to be able to identify reliable sources.Chjoaygame (talk) 14:00, 11 June 2015 (UTC)

Once again I extend the offer to send you the research provided you are not on the US government watchlist. This is not research that should be posted as a public link on wikiedia, however it is important new research which has a significant effect on the understanding of quantum theory.Derenek (talk) 14:05, 11 June 2015 (UTC)

Dear User:Derenek, I am sorry to need to tell you that you are acting on a great misunderstanding of the Wikipedia editing process. There are two kinds of issue: content, and conduct. You need to attend to both. The material you wish to post is inappropriate as to content. And your rapid undo of my undo, accompanied by your rapid undo of an edit on a related page, jointly tend in the direction of a conduct issue because repeated undos are forbidden. You have perhaps not yet actually violated in this, but you are close to it.

You seem to have ignored the reasons I wrote just above. Please read them carefully, to learn why your edits are inappropriate.Chjoaygame (talk) 14:33, 11 June 2015 (UTC)

Like I said, I am not a wikipedia author. I apologize if you took offense, I'm not an expert in using social media like wikipedia to disseminate knowledge. I just hope that somebody interested in understanding science read the paper prior to people deciding to erase it off the cuff.Derenek (talk) 14:47, 11 June 2015 (UTC)

Thank you for this reply. No offence felt. In words slightly different from those I wrote above, Wikipedia is not the place for very new research.Chjoaygame (talk) 20:57, 11 June 2015 (UTC)

Interpretations and 'reality'

In the introduction to the section "Tabular comparison", I've changed the sentence:

"No experimental evidence exists that distinguishes among these interpretations. To that extent, the physical theory stands, and is consistent with itself and with reality." to

"No empirical evidence exists that distinguishes among these interpretations. To that extent, the physical theory stands, and is consistent within itself and with observation and experiment."

My reason for doing so is that - as the table makes clear - different interpretations of QM present, in effect, different pictures of reality. There is thus no single, generally accepted concept of reality that QM could be consistent with. For example, there is surely a fact of the matter as to whether or not our universe is deterministic, but different interpretations give different opinions about this reality. Peter Ells (talk) 19:17, 12 August 2015 (UTC)

Branching space-time theories

I note that the only source for this section is a paper hosted on a pre-print archive that doesn't appear, from my searches, to have been accepted for publication by any journal. Is this adequate sourcing for a section of a scientific article? 86.24.88.241 (talk) 07:58, 21 September 2015 (UTC)

IP User:86.24.88.24, it would be good, if you intend to join these conversations, if you would choose and register for yourself some identity-non-revealing User name. It is hard to converse with a number. I think no security problem arises from a non-identity-revealing User name.

It is good to see you question sourcing as you have done. If that's the source, it's definitely inadequate. Definitely. If that's all the sourcing, the item should be deleted. If there is more sourcing, that needs to be very very carefully scrutinized; it's likely also to be inadequate, and again the item should be deleted.

From here, the phrase "branching space-time" looks like an extreme example of the tail wagging the dog. Or like a man who was a moment ago sitting on a tree-branch, now having sawn through the part between him and the trunk. Muddled thinking about quantum mechanics leading to bizarre fantasy about nothing real.Chjoaygame (talk) 11:23, 21 September 2015 (UTC)

Agreed, deleted. Waleswatcher (talk) 23:16, 21 September 2015 (UTC)

Chjoaygame, it is no harder to converse with a number than with a silly pseudonym. Please stick to responding sensibly to the content of comments rather than adding patronising clap-trap about registering. My non-registration is not a question of security, but of believing in Wikipedia's mission to be an encyclopedia that anyone can edit. 86.24.88.241 (talk) 21:42, 2 October 2015 (UTC)

If the history of a system is added to its state, then this eliminates interference resulting in a non-quantum system. JRSpriggs (talk) 10:24, 22 September 2015 (UTC)

History of interpretations

This section is incomprehensible unless you already know what all the terms mean, it's very badly written. — Preceding unsigned comment added by 82.139.82.82 (talk) 21:23, 15 November 2015 (UTC)

undid inappropriate "correction"

I undid a good-faith "correction" that replaced a link to a mathematical article with one to an article about electron density. The mathematical link is definitely to be preferred because, rightly or wrongly, 'electron density' has a connotation of Schrödinger's view that the electron was smeared. Born is emphasizing the probabilistic point-particle viewpoint, contrary to Schrödinger's.Chjoaygame (talk) 22:10, 3 December 2015 (UTC)

instrumentalist interpretation — copied from archive 4 because of no response

The article now gives pre-eminence to an interpretation that the article labels "Instrumentalist description". Reading the description I see that it refers to the primary interpretation proposed by Max Born, and subsequently very widely accepted. The presentation might give the impression that somehow the "instrumentalist description" is not an interpretation but is somehow more absolute, somehow "bare" of interpretation. The description says, apparently believing it, that "By abuse of language, a bare instrumentalist description could be referred to as an interpretation, although this usage is somewhat misleading since instrumentalism does not attempt to assign physical meanings to particular mathematical objects of the theory."

Instrumentalism assigns the meaning of probability to the quantities derived from the wave function. Probability is how the physical observations are analyzed. That is the key interpretation proposed by Max Born.

The description uses terms such as "state preparation processes", "measurement processes", and "initial conditions". These are very much interpretative in nature, and the subject of much discussion. They assign physical meanings to particular mathematical objects of the theory, such as for example wave functions.

Some writers regard Bohr as "instrumentalist", but he is almost by definition "Copenhagenist".

In effect, the so-called "ensemble interpretation" claims to be instrumentalist because it claims its assumptions are minimal, which is the claim of "instrumentalists".

The "instrumentalist" interpretation would deceive itself if it imagined that it is not an interpretation. Such a self-deception would work on the principle "What I think is fact, and infallible, while what you think is opinion, and fallible." No, sorry, what the "instrumentalist" thinks is opinion too. Very good opinion, no doubt, but still opinion.

"Instrumentalism" is a claim to some kind of superiority on the claimed ground of some kind of logical parsimony, but really it is just a claim to superiority that can avoid the ordinary requirements of scientific justifying argument.

I am not now editing to correct that error, but am leaving it to the current very active editor to put the instrumentalist view in a more proper place in the article.Chjoaygame (talk) 08:13, 19 April 2015 (UTC)Chjoaygame (talk) 12:05, 19 April 2015 (UTC)Chjoaygame (talk) 23:18, 19 April 2015 (UTC)Chjoaygame (talk) 03:16, 13 January 2016 (UTC)

Tabular Comparison

Does anyone who is active on this page know the history of how the tabular comparison was made? I am interested in clarifying this table and sourcing it. As of now it contains no true citations. My interest in the table is for the purpose of pedagogy - it is of great importance that the table be sourced and accurate as possible. I am willing to do the research, but are very aware that someone must have already done much work on this and we don't need to reinvent the wheel - but we would like to verify and source it! I am new to wiki and am still learning the proper etiquette - please be patient and help me approach the issue of making changes according to the rules of Wiki. Thank you. — Preceding unsigned comment added by Qmskcc (talk • contribs) 03:55, 2 September 2015 (UTC)

I put some of the entries in. Good sources are difficult, as it is debatable whether some of these interpretations make any sense and they are not even mentioned in textbooks. Roger (talk) 16:58, 2 September 2015 (UTC)

Part of the reason for sources being hard to find is probably that the very categories of the table are dubious. You may consider re-examining them.Chjoaygame (talk) 17:46, 2 September 2015 (UTC)

Thank you for your comments. I agree with each of your points. I am going to go ahead and get started on the project, and I will post proposed changes before making any if I make discoveries that would justify such changes. I'm working with some physicists at UC Berkeley to find the sources and will also interview some of the experts to see what they think of this table. In some cases, it will be possible just to ask the living interpreters represented here what they think of their column/if it is correct or even meaningful etc. — Preceding unsigned comment added by Qmskcc (talk • contribs) 20:21, 5 September 2015 (UTC)

You can sign your posts yourself by use of four tildes. A good thing to do.

The table lists the ensemble interpretation as due to Max Born. The use of the term 'ensemble' is variegated and I think Born was a Copenhagenist. It would be good to be very very careful to define 'ensemble interpretation'; it isn't successfully done in the article. Personally I think the 'many worlds interpretation' is sheer drivel, a testament to far out loss of contact with reality! You have set yourself a hard task.Chjoaygame (talk) 00:24, 6 September 2015 (UTC)

Instead of grumbling, perhaps I should try to make some positive contribution. Here is a try. Dirac makes a relevant point in a way that may be helpful for analyzing the 'ensemble' dispute. Perhaps the following might be seen as labouring the obvious, but in this area, even the obvious seems disputable.

On page 15 of the first edition, Dirac writes "The solution of Maxwell's equations that forms the wave picture of the phenomenon represents one of the photons and not the whole assembly of photons. ... One must not try to establish any connexion between the absolute intensity of the waves and the total number of particles, which is in sharp distinction to the older ideas of the relations between waves and particles." In the second edition, and, in the very same words in the third, and again in the fourth, edition, Dirac writes on page 9: "What they did not clearly realize, however, was that the wave function gives information about the probability of one photon being in a particular place and not the probable number of photons in that place."

The term ensemble has diverse usages. Some probabilists express the probability of an adventure of a single photon by talking of a fictive abstract ensemble of its possible adventures. The probability is measured by counting elements of that ensemble. In practice, one repeats the one-photon experiment many times, and counts the several various outcomes, to derive an empirical estimate of the probability. Many photon adventures are involved, but they occur and are observed one by one. Born could be said to be an ensemble man because he thinks in terms of this form of expression. Evidently in the just foregoing, Dirac uses the word 'assembly' to refer to a single concrete adventure in which many photons occur and are observed simultaneously. One would say that Born's 'ensemble' is not Dirac's just foregoing 'assembly'. What meant by 'ensemble' is not the same everywhere.Chjoaygame (talk) 00:59, 8 September 2015 (UTC)

Gunter Ludwig translates Born's second, more definitive, 1926 paper thus: "... relationship with the probability so that in an assembly of identical, uncoupled, atoms the states occur with a definite frequency." Here Born is considering many atoms simultaneously co-existent close to one another, but still sufficiently far separate from one another to be "uncoupled". This is a single concrete occasion in which many atoms occur but are somehow imagined to be counted one by one to measure the probability. Another translation of the same source is "... related to the probability that in a collection of equal, uncoupled atoms, a state should occur with a certain frequency [multiplicity?]."

Born and Einstein, in many letters, debated the meaning of the wave function. There the word 'ensemble' is used many times. For example, in a commentary in translation, Born writes "Einstein admits that one can regard the 'probabilistic' quantum theory as final if one assumes that the ψ-function relates to the ensemble and not to an individual case. This has always been my assumption as well, and I consider the frequent repetition of an experiment as a realization of the ensemble."

I think the possibility of confusion about the word 'ensemble' is evident in this. Howsoever, I think most would say that Born is not an ensemble man, that, on the contrary, he is a Copenhagen man.

Not easy to classify different authors' views on the notion of an 'ensemble'.Chjoaygame (talk) 03:50, 8 September 2015 (UTC)

Back after some time. This will take time no doubt. Another difficulty seems to be that Born changed his mind over his life, and also seems to have possibly misrepresented his previous positions, ant least according to the historians. What you have provided does seem to justify Born as a Copenhagen man. The table as is claims that the only difference between Copenhagen and Ensemble is that Born was, in 1926, agnostic on certain issues. I'm curious on the agnosticism of determinism and hidden variables. I doubt his agnosticism stayed, if that was indeed his position in 1926. Do you know any evidence of that agnosticism?

Another point: while many columns pose some definition problems, I don't understand "unique history". It must be different than the kind of unique history involved in determinism and counterfactual definiteness. I've seen it mentioned in Griffiths' advocates. Any knowledge of where else? Qmskcc (talk) 02:15, 4 November 2015 (UTC)

Thank you for your careful thoughts, Editor Qmskcc. I feel that the literature on the interpretation of quantum mechanics verges on the incurable. Physicists are utterly determined to mess it up. They want to prove that they are cleverer than Einstein, and will do whatever it takes to convince themselves of that. The word 'ensemble' is a deep and subtle trap. The use of Bellspeak (see Newspeak; Bellspeak is a dialect of Newspeak) is one of the ways they do so. For me, whether or not Einstein had it right is not so important as it is to understand the physics.

For Born's views, you can look at the Born-Einstein letters, which continued till 1955. The Schilpp tome, with Born on pages 161–177, was published in 1949. I don't think Born changed his mind or misrepresented his previous positions. I guess it is possible to read things as if he did change, but I think he didn't change. You may find it useful to look at his 1949 book Natural Philosophy of Cause and Chance. In the chapter on pages 5–9, Born makes some distinctions that I find useful, independent of his views. He distinguishes the ideas of causality and of determinism. Within causality he distinguishes between what I call 'nomic' and 'singular' causation. On page 103, he writes "We have the paradoxical situation that observable events obey laws of chance, but that the probability for these events spreads according to laws which are in all essential features causal laws." My reading of this is that Born thinks that quantum mechanics preserves causality, at least with definite reservations. But he thinks determinism has been overthrown. Einstein said that he could accept it that God might gamble, but not that he would gamble according to deterministic laws! I think he means that if the laws of nature were really stochastic, we should expect to see it in the macroscopic classical world. Of course there are multitudes of physicists who do so see things. For example, one reads things such as "the universe came into existence by a quantum fluctuation." Personally, I was not present at the birth of the universe and I don't know what happened. At present I think Bohr didn't adequately distinguish causality from determinism (I reserve the right to change my mind about this, perhaps on further thought or study).

I am sorry to say I don't want to get myself more deeply into it here.Chjoaygame (talk) 07:12, 4 November 2015 (UTC)

Agnosticism of Copenhagen Interpretation RE Locality

The Copenhagen interpretation, in the table at the bottom of the article, is currently listed as "Agnostic" on its position with respect to Locality. I find this an incredibly dubious claim to make, Deutsch-Hayden arguments notwithstanding. If the Copenhagen interpretation is allowed to remain agnostic on this issue, then a host of other interpretations can likely be coerced to agnostic also. Porphyro (talk) 15:38, 24 February 2016 (UTC)

Perhaps Copenhagen should be changed to Yes. Is that what you are suggesting? Roger (talk) 18:20, 24 February 2016 (UTC)

Yes, that is what I'm suggesting. The alternative view isn't held by many, as far as I am aware. Porphyro (talk) 19:11, 24 February 2016 (UTC)

I'd also support renaming that column to "Dynamically local" or "locally causal" although that isn't quite accurate either. But many of the "Local" theories aren't local in the sense that Einstein meant, since the wavefunction is part of the ontology, aren't kinematically local and so aren't really "local". Porphyro (talk) 22:26, 24 February 2016 (UTC)