Talk:Bell's theorem/Archive 7

Thank you for this comment

Thank you for this comment. May I say, contrary to it, that the new section does not (repeat NOT) suggest, nor (repeat NOR) does Khrennikov suggest, that the "Bell's theorem experiments are flawed". For the sake of definiteness, I can add here that the section, and Khrennikov, gladly accept that the Bell's theorem experiments are not (repeat NOT) flawed. For more explicitness, perhaps I may add that the section and Khrennikov gladly accept that "we have (almost) [ir]refutable evidence that nature can violate Bell's inequality". The section and Khrennikov gladly accept that "an experiment demonstrating that nature never violates Bell's inequality" is not at all likely to be validly conducted. If by now there remains unclarity about this, please let me know, and I will try to clarify.

For support of my just foregoing comment, may I observe that the only use of the word 'experiment' in the section is as follows:

According to Bell, it is essential for the establishment of the causal implications of his inequality, that the experimental protocol be of the delayed-choice structure.^[1]

For definiteness, may I say that this sentence intends to agree completely with Bell on this point, and does not intend to impugn any experiment that might be performed.

No, the point made is about the theory in Bell's paper, his reasoning and argumentation, that generates the inequalities that the experiments test. It is the theoretical generation of the inequalities, not the experiments, that are the subject of the section and that are addressed by Khrennikov.

Since my just foregoing remarks interpret your comment as seeming to indicate that you are concerned that Khrennikov might be challenging the experiments, when the section intends that such is not his proposal, perhaps I may stop at this point, and see if we can review the situation, before going further.Chjoaygame (talk) 00:59, 3 October 2015 (UTC)

Thank you for clarifying your position. It was a relief to learn that you understand Bell's theorem. I now modify my complaint by stating that the following sentence is misleading:

When this factor is taken into account, the resulting inequalities are far less stringent, and are not violated by quantum mechanical predictions.

I assumed that the words "the resulting inequalities" refer to some modification of Bell's inequality that makes it more realistically model the experiment, for example by including missed photons or false detection of entangled photons. These complications were neglected in Bell's original paper. The phrase "not violated by quantum mechanical predictions" sounds like Bell's inequality is NOT violated when these effects are taken into account. First time readers will find it extremely confusing that Bell "derived" an inequality that is violated by both theory and experiment. Virtually all theoretical work focuses on deriving equations that are consistent with theory and experiment. So even if your section is technically correct, it is misleading.

When you write about Bell's theorem always keep in mind this peculiar fact: Bell's inequality is a quote-"prediction"-unquote that is violated by experiment and by quantum mechanics. Ironically one of the greatest discoveries in the recent history of quantum mechanics is an equation that is wrong. I often talk to students about Bell's theorem, and that is a big stumbling block. --Guy vandegrift (talk) 03:09, 3 October 2015 (UTC)

Thank you for your prompt and apposite response.

In my opinion, you are right to have "assumed that the words "the resulting inequalities" refer to some modification of Bell's inequality that makes it more realistically model the experiment". On the other hand, I should say that Khrennikov is not remotely imagining or suggesting that the modification is about "missed photons or false detection of entangled photons", or anything along those lines. Neither is Khrennikov suggesting that "Bell's inequality is NOT violated when these effects are taken into account". Khrennikov fully accepts that Bell's inequality is violated when these effects are taken into account.

Thank you for emphasizing the point that I (and, perhaps I may guess, Khrennikov) agree with, that "First time readers will find it extremely confusing that Bell "derived" an inequality that is violated by both theory and experiment." But the question is 'why will they find it confusing?'

The reason why they will find it confusing is not that Khrennikov is mistaken, nor that my posting of Khrennikov is wrong or misleading. They will find it confusing because they have already in their minds the idea that Bell validly derived an inequality that refers to the experiments. The reality is, according to Khrennikov, that Bell's inequality does not validly refer to the experiments. First time readers, and many readers who have read it a hundred times in the past, suppose that Bell's inequality and its congeners are validly applicable to the experiments.

Khrennikov is pointing out that the inequality that validly applies to the experiments is different from Bell's, and more particularly, from the CHSH, inequality. Bell's 1964 paper gives the reason for this. The last words of the conclusion of Bell's text are as follows:

Of course, the situation is different if the quantum mechanical predictions are of limited validity. Conceivably they might apply only to experiments in which the settings of the instruments are made sufficiently in advance to allow them to reach some mutual rapport by exchange of signals with velocity less than or equal to that of light. In that connection, experiments of the type proposed by Bohm and Aharonov [6], in which the settings are changed during the flight of the particles, are crucial.

It is evident, from the fact of these being the last words of his conclusion, and from the idea they express (the need to follow the delayed-choice protocol) not being expressed earlier in his paper, that Bell's derivation does not take that idea into account. Uniformly, other writers, following Bell, produce derivations of congeners of Bell's inequality that also do not take that idea into account. Khrennikov's paper, that is reported in the section, shows how to take it into account through valid orthodox probabilistic reasoning. The result is an inequality that indeed validly refers to and applies to the experiments, but is different from Bell's and its congeners'. The experiments do not come near violating the inequality that Khrennikov validly derives.

That the inequality that Khrennikov derives is not violated by the experiments is consistent with the validity of Khrennikov's derivation. As it happens, Khrennikov's working with conditional probabilities was to a degree anticipated, though not completed, by Edwin Thompson Jaynes.^[1]

The problem is not with Khrennikov's derivation, nor with his result, nor with the section's report of them. The problem is that Bell's inequality, as derived by Bell, and of its congeners as derived by his followers, makes no pretence to take into account the last words of Bell's 1964 paper that I have quoted just above. Those Bell inequalities and their congeners, accordingly, cannot pretend to apply to experiments that follow the delayed-choice protocol. Readers who supposed the contrary would be confused.

But their confusion does not arise from a mistake by Khrennikov, nor, I submit, from the section that I posted being misleading or mistaken. To find the source of their confusion, they must look not there, but instead must look at their supposition that Bell's inequality and its congeners refer validly to the experiments. The bulk of the article would, of course, support their supposition. That is why the section is headed 'Alternative analysis'.Chjoaygame (talk) 05:28, 3 October 2015 (UTC)

Is the Khrennikov paper freely available online or can anyone send be a copy please? Martin Hogbin (talk) 13:07, 3 October 2015 (UTC)

what is happening?

I do not understand, what is happening. Yes, of course, "experiments ... in which the settings are changed during the flight of the particles, are crucial"; doing otherwise is one of the loopholes well-known since 1964, isn't it? So, what could be the new point made by Khrennikov in 2015? Maybe this matter (if at all) should go to "Loopholes in Bell test experiments"? Boris Tsirelson (talk) 06:11, 3 October 2015 (UTC)

Thank you, very much admired and respected Editor Tsirel, for your very welcome comment.

Perhaps I may approach the question again. I think all agree that, broadly speaking, the so-called "Bell" experiments are sound when considered as experimental facts. The agreed experimental facts are that the observations violate the Bell and congener inequalities. So far as I can see, all will agree on that. If not, please let me know, and I will consider the reasons offered.

The questions arise as to interpretation of this violation.

I think most will agree that because the experimental facts contradict the Bell inequalities, there must be something very wrong with any purported "derivation" of those inequalities. This means that, in particular, there must be something very wrong with Bell's derivation. So far as I can see, all will agree on that. If not, please let me know, and I will consider the reasons offered.

What is wrong with the Bell derivation?

I guess the currently most celebrated diagnosis, of the fault in Bell's "derivation", is that Bell's "derivation" makes some wrong physical assumptions, more or less along the lines that 'nature would follow classical physical thinking'.

Under the heading 'Alternative analysis', the section takes the line that such a currently celebrated diagnosis differs profoundly from the diagnosis that is to be found in Khrennikov's paper. No, Khrennikov's paper does not endorse that currently celebrated physical diagnosis of the fault in Bell's "derivation". Instead, Khrennikov's paper diagnoses a logical, not a physical, defect that makes Bell's "derivation" inapplicable to the experiments. That is to say, Bell's "derivation" does not use conditional probabilities when they are needed for a valid derivation that can refer to the experiments. The diagnosis is not physical failure; it is logical, failure to conduct valid probabilistic reasoning.Chjoaygame (talk) 07:52, 3 October 2015 (UTC)

I still guess that our "Metaphysical aspects" section mentions all known ways to escape Bell inequality. What does it mean here, "logical, not physical"? When the physical assumptions are carefully formulated, Bell theorem becomes just this: a mathematical theorem that is a logical consequence of the assumptions. Rigorously. Do you want to say that Khrennikov is able to be more rigorous than the mainstream mathematics (including, of course, the probability theory, as is)? Even though the mathematics is now available to formal computerized verification? Boris Tsirelson (talk) 10:06, 3 October 2015 (UTC)

Thank you for this response. It is good to see that you take this seriously. Nevertheless, you do not make it clear, as to whether or not you have read Khrennikov's paper; at face value, your reply gives me the impression, perhaps mistaken, that you have not read Khrennikov's paper; please tell me this impression is mistaken, or please read the paper. As a piece of persuasive rhetoric, your response is fine. But your response does not pretend to address explicitly and directly the logical issue raised by Khrennikov.

Instead, your response just asks me what do I want to say, asking my opinion about Khrennikov's rigour? Your response presupposes, but does not offer reasons for, the idea that Khrennikov is not using "mainstream mathematics, including probability theory , as is". My answer is that Khrennikov is indeed using mainstream mathematics including probability theory, as is. The failure of Bell's "derivation" to use mainstream conditional probability where it is needed, as in this case, was pointed out in 1988 by none other than E.T. Jaynes, as cited and linked above. For the benefit of this discussion, may I point out that a major element in Khrennikov's presentation is his approving citation of the contribution of one Boris Tsirelson. I do not know if you are that Boris Tsirelson; perhaps you may wish, or not, to enlighten me on that point; by default, I am supposing you are he. I am nowhere near qualified to pass judgment on Tsirelson's work, because I am nowhere near him in knowledge and scholarly stature, but my unquestioning personal assumption is that Tsirelson's work is undoubtedly correct.

For definiteness, it may be useful if I here quote Khrennikov's paper:

Therefore “quantumness” is characterized not by a violation of the inequality (34), i.e., not by the experimentally confirmed fact that |Q₁₁ + Q₁₂ + Q₂₁ − Q₂₂| can be larger than 2, but by the Tsirelson bound 2√2. This cannot be explained in the classical Kolmogorov framework.^[1]

For clarity, I should add that by the "the classical Kolmogorov framework", Khrennikov means 'the most basic form of the Kolmogorov framework', that does not explicitly deal with conditional probability. Of course, Khrennikov accepts the basic form of the Kolmogorov framework, as do all, including me. Conditional probability is of course an established mainstream offspring of the basic Kolmogorov framework. As a detail, it seems that Khrennikov assumes that the reader is so well familiar with the work of Tsirelson, that, most regrettably, Khrennikov does not actually give the reference for the relevant paper by Tsirelson; I here supply the latter for the English translation, according to my reading: Tsirelson, B. (1985/1987). 'Quantum analogues of the Bell inequalities. The case of two spatially separated domains', Journal of Soviet Mathematics, 36(4): 557–570. This can easily be downloaded from the internet for free. If I am mistaken here, of course I will defer to proper correction.

The Khrennikov diagnosis is that the Bell derivation does not refer to the experiments because of a logical disqualification, namely failure to use conditional probability when it is needed. Consequently, the physical assumptions of the Bell derivation have no applicability, and no relevance.

In a nutshell, the choice of each occasion of analyzer setting is part of the physical content of the experiments, and should be taken into account as conditioning the relevant probabilities, a thing not done by the Bell derivation and its followers. So to fail is an error of logic, not a physical error.

With great respect for your fine erudition, I feel that this matter may best be advanced here if you tell us what you think of Khrennikov's reasoning when you have read his paper.Chjoaygame (talk) 13:41, 3 October 2015 (UTC)

Well, for now, just two simple bits of information that you like to know: (a) indeed, I did not see Khrennikov's work (yet); (b) really, I am that Tsirelson; proof: "his" website (in Tel Aviv university) contains a link to "my" userpage here. Boris Tsirelson (talk) 16:19, 3 October 2015 (UTC)

Thank you for this. I await your further post.Chjoaygame (talk) 17:23, 3 October 2015 (UTC)

OK, I saw his article. First of all, I know that my opinion is not a reliable source; no matter which Tsirelson I am, here I am just one of numerous editors of WP. This being said, here is my first impression.

It was my preconception that Bell inequalities follow evidently from Bell's assumptions; and therefore someone that fails to get these inequalities, necessarily uses different, nonequivalent assumptions. And this is the case. By conditioning on the pair of inputs, the author opens the door for contextuality. And so, not unexpectedly, he escapes Bell's framework. Such a model generally cannot be embedded into the framework of local hidden variables ( = "local realism" = "counterfactual definiteness + relativistic local causality + no-conspiracy" = ... ). It is of course important that Bob's input cannot influence Alice's hidden variables. If someone chooses to escape Bell theorem by admitting that Bob's input does influence Alice's hidden variables, well, he'd better say so explicitly. Just to be more clear to physicists in his position, than speaking about Kolmogorov's probability theory etc. As usual, by admitting this hidden faster-than-light communication, he gets CHSH=4 (rather than 2) and then wonders, why we never observe this.

So, what about the article in Wikipedia? The question is, how notable is this reliable source. My impression is that, if out threshold admits this source, then it admits quite a lot of other sources that discuss (non)contextuality and many other possible thoughts inspired by Bell theorem. Or maybe "Quantum contextuality" is the right place for it? See his first phrase on his last page 723: "It seems that there the key word is contextuality". Boris Tsirelson (talk) 17:36, 3 October 2015 (UTC)

Sad to say, your last added fragment has created an edit conflict which makes my last half-hour's work inaccessible to my machine's editor. I would need to re-type every word again in order to reproduce it. I will think it over.Chjoaygame (talk) 19:11, 3 October 2015 (UTC)

Oops... I am really sorry, but not guilty. I was many times in such situations, the last time - just here, today, because of you! (You are not guilty, of course.) But, seeing the edit conflict, I did "copy" of my text (by mouse) and later, "past"; my text was not long. I would never create a long text with no backup. Maybe, because I worked 10 years as a programmer? :-) Boris Tsirelson (talk) 19:39, 3 October 2015 (UTC)

thank you

Thank you for this very interesting comment. Beyond saying that I think the sources that I have so far encountered fail miserably to provide an even remotely adequate, consistent, and coherent point of view about which one could be either happy or unhappy, and I am very unhappy about that failure, for the present I will refrain from further reply because it is forbidden to use this page as a discussion forum as distinct from an article forge. I will think about it. Perhaps personal talk pages suggest themselves?Chjoaygame (talk) 10:07, 4 October 2015 (UTC)

As a physcist (of sorts) I fit firmly into the 'be happy with the predictions and the point of view' camp but I am stll interested in the results of Bell tests.

I have just seen the Khrennikov paper and have not followed all the maths yet but my initial impression, from reading just the abstract, is that there might be something in it. It would be a pity if Bell tests were made even harder but if that is the case we just have to accept it. Martin Hogbin (talk) 16:57, 4 October 2015 (UTC)

Hmm. I read it the other way !! As I read it, the Khrennikov view is that the tests, properly analyzed, are so easy you can drive a truck through them. The customarily celebrated tight tests are just artefacts of mistaken logic, if construed as tests of metaphysical positions, such a 'locality'. The Bell tests, as they are celebrated, just corroborate that every experiment can be analyzed, though only up to a point, in terms of waves, and in terms of particles, and no experiment, with genuine quantum phenomena, can be fully analyzed by either waves or particles alone.Chjoaygame (talk) 17:40, 4 October 2015 (UTC)

Now I see

Now I see. The ad hoc term 'context' is a way of using Jeffreys' idea that a statement of the data on which it is based must accompany every statement of a probability, without acknowledging Jeffreys' priority. In more detail, for example, the expression 'the probability of detecting a prescribed position state of a particle, given the detection of its prescribed momentum state' has no meaning, because the prescriptions are inconsistent and inadequate. On the other hand, it does make sense to speak of 'the probability of detecting a prescribed position state of a particle, given its preparation in a prescribed momentum state', because the prescriptions are consistent and adequate.Chjoaygame (talk) 14:56, 4 October 2015 (UTC)Chjoaygame (talk) 15:30, 4 October 2015 (UTC)

Well, now I understand the direction of your (and Khrennikov's, and some other's) thinking. The direction is itself OK, but this is not about Bell inequalities! Bell inequalities, BY DEFINITION, are inequalities that must be satisfied under LOCAL REALISM (there are several equivalent terms, choose any one, this one is the shortest, if not the best). If you are not interested at all in local realism, OK, this is your right. But then, you are not interested at all in Bell inequalities. Thus, again, this part of the discussion (as well as Khrennikov's work) should go to the article on contextuality. (There you may argue that the term is historically wrong, if you like.) Boris Tsirelson (talk) 16:15, 4 October 2015 (UTC)

Hmm. I am not quite in agreement with some of this. I guess that's because I don't have any confidence that the metaphysical term LOCAL REALISM has a definite physical meaning. I would define Bell inequalities as inequalities proposed by Bell. Since I don't trust his logic, I have no confidence that they have definite physical or metaphysical import. If local realism means the same as 'no action at a distance', I am interested in it. But the "realism" side of it leaves me distrustful, because I am not confident what it might mean. The fallacy of misplaced concreteness hovers all over it. Perhaps I should follow your advice and go to the article on "contextuality". Let's see.Chjoaygame (talk) 17:53, 4 October 2015 (UTC)

It seems you know what is meant by 'no action at a distance' in a universe without counterfactual definiteness! I do not. The no-signaling condition seems to me rather a surrogate, or an implication, of 'no action at a distance'. Boris Tsirelson (talk) 19:36, 4 October 2015 (UTC)

Touché! I guessed you might ask what does one mean by 'no action at a distance', but thought I would wait till you asked. I have to concede I don't have an answer any better than I do about 'local realism'. I'm sure I don't know any better than you or the next man! It's just that I prefer, without a very strong reason, the more traditional wording, rather than the newfangled term 'local realism'!! I suppose what I mean by 'no action at a distance' is the same as 'finite speed of propagation of causal efficacy'; I guess that would raise a laugh from some!

The orthodox quantum doctrine, with which I agree, is that if you want to find out something from nature, you have to design a question and a set of experiments that explicitly and directly address that something. So if one wants to find out the speed of propagation of "influence", one should do an experiment that measures speed. But time and distance appear nowhere in the Bell story: so it doesn't allow a deduction about speed, infinite or not. Another way of looking at it is to remember the rule against arbitrary deduction from a contradiction.

It seems, you take "the Bell story" quite literally: just the text of the Bell 1964 article. Why? I do not. For me "Bell story" is the great story initiated by that article. Including later articles by Bell, and numerous articles by others. Accordingly, (1) for me "Bell inequality" means every inequality on observed probabilities that follows from local realism; (2) time and distance do appear. (Just look at my article on Citizendium, linked above.) For example, it is well-known during decades that Bell inequalities are violated in the vacuum state; this is interpreted within the quantum field theory; needless to say, space/time/relativity is crucial. Boris Tsirelson (talk) 06:02, 5 October 2015 (UTC)

Near enough. I speak of 'Bell inequalities and their congeners'. I think we refer to the same inequalities. I am not, however, comfortable in speaking in terms of "hidden variables" and "local realism", as I suppose is by now obvious. I am unpersuaded by the methods of reasoning that rely on those terms.

We are getting close to some deep water. I haven't yet looked at your article but will do so quite soon. Perhaps it may help here if I quote from the Wikipedia article on Hidden variable theories and comment on the quote:

Einstein, Podolsky, and Rosen argued that "elements of reality" (hidden variables) must be added to quantum mechanics to explain entanglement without action at a distance.^[1][2]

Let me comment on that sentence. I think it puts words into mouths of the authors which they did not speak, and I find that procedure a recipe for endless consequent muddle. I think the EPR 1935 paper suffers from grave logical problems that are not well criticized by the usual literature on "hidden variables". At a rough guess, perhaps more useful criticism may be found in terms of Jaakko Hintikka's 'Independence Friendly' (IF) logic. I previously claimed that I wanted orthodox logic and here I am proposing something that might be seen as slightly different. So we are, as I said, getting close to some deep water. I guess I have to say I find the usual literature on hidden variables (how shall I put it?) not to my taste. For this kind of work, one needs serious cosmology in the sense of Alfred North Whitehead. Whether Whitehead's own cosmology is adequate for the present kind of work, I am not confident. But I am confident that seriously professional cosmology (in that sense) is needed. I will look at your article on Citizendium, linked above. I think we will not sort out the present questions very easily or quickly.Chjoaygame (talk) 08:18, 5 October 2015 (UTC)

Oh yes; we will not. Here is a kind of a proof of this no-go theorem. :-) Looking at my reminiscence on IQOQI blog here you can see that the shock from the Bell theorem is a fundamental fact of my biography. An intellectual drama (or even tragedy?) of my youth. It is possible, in principle, to convince me that the inequalities hold, or not, conform to views of Einstein, or not, etc.; or even, that I am very stupid, from my youth onward. But it is impossible, in principle, to convince me that they are not shocking, since the assumptions are not reasonable. For me they are, absolutely. Boris Tsirelson (talk) 09:54, 5 October 2015 (UTC)

I too was rather surprised to learn of the Bell story. My immediate reaction was to think there must be something wrong with the reasoning. This was because I don't believe in action at a distance, and I do, in general, believe in causality. Dare I say it, I have a suspicion that much of our difficulty derives from the way Niels Bohr set the tone of the thinking. I am not disagreeing with any particular thing he said. Rather I am saying that I think he set our thinking in an unfruitful frame, from which we can't easily escape. I have to accept that this is a nearly meaningless thing to say. But it's my best guess.

Quantum mechanics has the isolated system obey the Schrödinger equation. That is deterministic. The stochastic element comes in when one makes the isolated system collide with another system, the observing apparatus. I suppose the observing apparatus might have been obeying its own Schrödinger equation, again deterministic, until the collision. But we don't pretend to know a Schrödinger equation jointly for the two after the collision. I think our lack of knowledge of a suitable joint Schrödinger equation does not make the physical world lack obedience to a joint Schrödinger equation, which again is deterministic. A closely related problem, I think, is in thermodynamics. A thermodynamic process is initiated by a thermodynamic operation. The thermodynamic operation just appears out of nowhere, a true deus ex machina. Thermodynamics makes no effort to deal with it. Perhaps it is the work of Maxwell's demon? This doesn't shock me. I think something along these lines may help with the Bell problem.Chjoaygame (talk) 11:24, 5 October 2015 (UTC)

If the physical world, accurately described as it is by quantum mechanics, really were weird and magical as too many try to persuade us, it wouldn't let itself be restricted by Tsirelson's bound; it would go all out, as in this story about toy systems. If someone isn't bound by such constraints as Tsirelson's bound, why would he stop there? Might as well be hung for a sheep as for a lamb. For me, this points to a physical world that obeys causality, even though it cannot be verified by singular direct observation.Chjoaygame (talk) 12:02, 5 October 2015 (UTC)

Oh, the quantum/classical boundary is a vast and complicated matter... But! My admiration for Bell is first of all due to the fact that his argument disentangles us from this vast and complicated matter. Bell theorem shows that Nature is not a classical mechanism; and what is the input from the quantum theory? Only a single prediction, of purely informational nature (thus, no matter what kind of particles we use, and whether they are particles, at all). Bell theorem establishes a direct connection between fundamental assumptions and empirical facts, over the head of the quantum theory. As long as the prediction is experimentally verified, I can forget all ideas of Bohr, Schrödinger etc.

Thus, I think, seriously, that these ideas of Bohr, Schrödinger etc should not be discussed here. (On personal talk pages, they may.) This is not wikilawyering, this is the essence of Bell's approach. Boris Tsirelson (talk) 12:22, 5 October 2015 (UTC)

This is sometimes called "experimental metaphysics": a single experiment can give us a fundamental knowledge about Nature irrespective of any theory at all (in particular, of quantum theory). Bell have discovered the very existence of experimental metaphysics. Unprecedented! Boris Tsirelson (talk) 12:53, 5 October 2015 (UTC)

It looks as if we have gone as far as we can for now? We have aired some ideas which may develop. Perhaps some further progress may come in future. I will look forward to that. It has been a great privilege and pleasure for me to chat as we have. Thank you.Chjoaygame (talk) 12:46, 5 October 2015 (UTC)

Happy editing. Boris Tsirelson (talk) 12:53, 5 October 2015 (UTC)

I am not quite sure which article you are indicating. I have now downloaded and will shortly read this one. Is it the one you mean?Chjoaygame (talk) 08:56, 5 October 2015 (UTC)

Oops, no, sorry for being misleading; I mean this. Boris Tsirelson (talk) 09:44, 5 October 2015 (UTC)

No worries. I am learning all the while. Thank you for this. I will read it.Chjoaygame (talk) 10:20, 5 October 2015 (UTC)

Ah, yes, now I recall glancing at this, but it slipped my mind. I will now read it with attention.Chjoaygame (talk) 10:32, 5 October 2015 (UTC)L

Yes, I now recognize that I did read this, but it didn't all lodge in my memory. There is quite a lot in it. My own approach to these puzzles is to try to hold close to a physical picture, if such is possible. What is a physical picture? I don't have a ready answer. I won't try to answer right now.Chjoaygame (talk) 10:46, 5 October 2015 (UTC)

There, "bibliography" and "external links" are separate pages. Boris Tsirelson (talk) 10:56, 5 October 2015 (UTC)

Coming back to 'contextuality'. I have to say that I think that the rule proposed by Jeffreys, that a statement of the data on which it is based must accompany every statement of a probability, is normal ordinary routine logic, not something special and peculiar that justifies a new label and a separate article "contextuality". My instinct is that a breach of the Jeffreys rule is automatically wrong and a violation of ordinary logic. One encounters, on the other hand, an attitude that I find bizarre and crazy, that somehow a quantum experiment or theory could overthrow ordinary logic and justify a new "quantum logic". The quantum theory is written in the language of ordinary logic. To overthrow ordinary logic is to send everything back to the drawing board, including quantum theory; not for me, thanks very much! A departure from the Jeffreys rule is, I think, mere carelessness or incompetence. I think it safer to take the Jeffreys rule as part of normal reason.Chjoaygame (talk) 00:38, 5 October 2015 (UTC)

If it is contemplated that last-moment switching of the near analyzer setting might affect what happens at the far observation station, it would be natural to expect that such switching would have potentially far greater effects on what happens at the near station. Once it is contemplated as effective, who knows what might be the effects of the switching? It is part of the experiment.Chjoaygame (talk) 02:37, 5 October 2015

If anyone has had so much time to spare as to have glanced at my above comments, perhaps it may help if I quote Khrennikov as follows:

I have had numerous conversations with outstanding physicists. A rather common opinion is that it is totally meaningless to pay attention to foundations of probability theory.Typically such a viewpoint is motivated by considering probability as a “physically well-defined quantity.” Therefore one need not seek a mathematically rigorous probabilistic formalization.

I totally disagree with such a viewpoint. In the same way one might say that physicists need not take note of mathematical models of space and geometries.^[1]

And from Kolmogorov:

In consequence, one of the most important problems in the philosophy of the natural sciences is—in addition to the well­ known one regarding the essence of the concept of probability itself—to make precise the premises which would make it possible to regard any given real events as independent. This question, however, is beyond the scope of this book.^[2]

Khrennikov does a lot of talking, and it takes a while to find the core of what he is on about. Much of his basic thinking is hardly different from that of Harold Jeffreys, and it disappoints me that it seems Khrennikov did not read Jeffreys.^[3][4]

Or perhaps for some very odd reason Khrennikov did not see how close are his and Jeffreys' ideas on probability. The key is simple, as above: a statement of the data on which it is based must accompany every statement of a probability. Chjoaygame (talk) 03:18, 7 October 2015 (UTC)

article on quantum contextuality

I have now followed your advice and had a look at the article entitled Quantum contextuality. I am not sure what I should say as a result.Chjoaygame (talk) 04:57, 5 October 2015 (UTC)

In the opinion of Khrennikov:

     The main terminological problem is related to the notion of contextuality.The use of the term “contextual” is characterized by a huge diversity of meanings, see Bell [34], Svozil [296] or Beltrametti and Cassinelli [35] for the notion of contextuality in quantum physics ...

     ... In quantum physics the contextuality is typically reduced to a rather specific contextuality—“Bell contextuality.” J. Bell invented this notion in the framework of the EPR-Bohm experiment [34, 35]. We recall that such quantum contextuality (“Bell’s contextuality”) is defined as follows.

     The result of the measurement of an observable a depends on another measurement of observable b, although these two observables commute with each other.

     It should be emphasized that the nonlocality in the framework of the EPR-Bohm experiment is a special case of quantum contexuality. ...

     Our contextuality is essentially more general than Bell’s.^[1]

On looking at the reference Beltrametti & Cassinelli (1984), one finds that built into their definition of "contextuality" is the presupposition of "hidden variables".

On looking at the reference to Svozil, I can only say it confirms my view that the term 'contextuality' is a recipe for muddle.

Speaking more generally, it seems to me that the term 'contextuality', though used just barely reasonably but still unfortunately, perhaps to satisfy the watchdogs, by Khrennikov, is a brilliant masterpiece of obfuscation or intellectual coersion that puts George Orwell's 1984 Newspeak in the shade.

For those unfamiliar with Orwell, Newspeak is a synthetic language, enforced by the state, so constructed that it is practically impossible in it to express thoughts other than those authorized by, or pleasing to, Big Brother. It ensures that ordinary truth is inaccessible, and that nonsense prevails unchallengeably, making doublethink seem natural.

Khrennikov uses the term 'contextuality' in a safe way, though I think he would have done better to avoid it because it is saddled with crippling handicap in the wake of Bell's use of it.

Once one starts using the term 'contextuality' as if it were an ordinary-physical-usage word in the present context, without very particular and well-advertised precautions (such as, for example, Khrennikov's), one is almost sure to talk nonsense.Chjoaygame (talk) 18:27, 11 October 2015 (UTC)

Maybe. I can only add that I was always bored by contextuality, and has never been willing to think seriously in this direction. Boris Tsirelson (talk) 19:06, 11 October 2015 (UTC)

section deleted

I have thought it over, and have deleted the section because it relies only on primary research in a journal, which is not adequate as a reliable source.Chjoaygame (talk) 21:02, 3 October 2015 (UTC)