# Talk:Bell's theorem

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## Unclear on the intuition of some text

"Suppose the two particles are perfectly anti-correlated—in the sense that whenever both measured in the same direction, one gets identically opposite outcomes, when both measured in opposite directions they always give the same outcome. The only way to imagine how this works is that both particles leave their common source with, somehow, the outcomes they will deliver when measured in any possible direction. (How else could particle 1 know how to deliver the same answer as particle 2 when measured in the same direction? They don't know in advance how they are going to be measured...)."

The above is an unsourced (perhaps OR) intuitive argument the intuition of which dose not jibe with my own understanding.

The particles in question are photons which are observed. Thus, they are photons that have been both emitted and absorbed. When a photon is emitted and absorbed, it has traveled at the speed of light and, from the photon's perspective, the emission and absorption have happened simultaneously, coupling and conserving mass-energy and spin angular momentum from the emitter to the absorber.

Similarly when a pair of entangled photons is emitted and absorbed, the emission event, and the two absorption events happen simultaneously, again from the photons' perspective, and again conserving spin angular momentum. So the photon does not have to "know" what these angular momenta are while in transit, as from the photon's perspective, the entire coupling event has happened in a single instant, is a single event and there was no concept of being "in transit".

The fact that the two distantly separated absorbers are measured as not being co-located, by some observer, who is neither of the photons, is explained because that's how special relativity works. In different frames you measure different distances and times. The coupling must make sense from the frame of the force-coupling carrier(s), but not from anybody else's frame. So there is no FTL communications paradox, at least not in this example involving photons in a vacuum.

Spope3 (talk) 06:03, 7 May 2015 (UTC)

Maybe. But the effect is the same on electrons and even heavy ions, that are far not massless. That "the emission and absorption have happened simultaneously" is itself not a well-established point of view. Moreover, bare photons are massless but do not exist in reality. Dressed photons are not quite massless because electron-positron virtual pairs matter. Boris Tsirelson (talk) 07:16, 7 May 2015 (UTC)

== (Reply to Boris re. "unclear intuition")

I have two points here:

1) Although the effect "is the same" for electrons and heavy ions, the article makes it clear that the most serious experimental results come from studying the behavior of photons. So it is at this point speculative to say that similar results hold for electrons (although I personally believe they do).

2) It is true that all real-world photons behave as dressed photons. But I'm not sure this means undressed photons don't exist, to me it means that a perfect vacuum does not exist, at least in our section of the universe/multiverse. So a photon might scatter off particles other than its Bell-experiment target (including virtual particles, and this effect can be translated into a mass expression for a dressed photon, but if this happens the Bell-experiment outcome is different whether or not one leans towards my point of view or the article's statements. — Preceding unsigned comment added by Spope3 (talkcontribs) 02:02, 8 May 2015 (UTC)

Looking at recent work from the Hanson group in Delft I see that a Bell test experiment is presently underway using electrons in diamonds. "Entanglement swapping" uses entangled photons to create entanglement between electrons in widely separated in locations in imperfections in carbon crystals (diamonds). Replace one carbon atom with a nitrogen atom and you have an addressable electron. Take a look at http://hansonlab.tudelft.nl/publications/ and at http://www.tudelft.nl/en/current/latest-news/article/detail/beam-me-up-data/ Richard Gill (talk) 16:43, 4 August 2015 (UTC)

## Aug 2015 experiment Experimental loophole-free violation of a Bell inequality using entangled electron spins separated by 1.3 km

New experiment, results to be peer reviewed. May be a future addition after peer review agrees with the results. http://www.nature.com/news/quantum-spookiness-passes-toughest-test-yet-1.18255?WT.mc_id=TWT_NatureNews http://arxiv.org/abs/1508.05949 JScience 17:04, 29 August 2015 (UTC)jcardazzi

Very nice, thank you!
And please sign your remarks (on talk pages) with four tildas: ~~~~. Boris Tsirelson (talk) 17:44, 29 August 2015 (UTC)

See also https://en.wikipedia.org/wiki/Bell_test_experiments (and perhaps also https://en.wikipedia.org/wiki/Loopholes_in_Bell_test_experiments) Richard Gill (talk) 06:34, 5 September 2015 (UTC)

Final Loophole David Kaiser Additional thought:The experiment has closed two of the three major loopholes beautifully, but two out of three isn’t three,” Dr. Kaiser said. “I believe in my bones that quantum mechanics :::is the correct description of nature. But to make the strongest statement, frankly we’re not there.”
A potential weakness of the experiment, he suggested, is that an electronic system the researchers used to add randomness to their measurement may in fact be predetermined in some subtle way that is not easily detectable, meaning that the outcome might still be predetermined as Einstein believed.
To attempt to overcome this weakness and close what they believe is a final loophole, the National Science Foundation has financed a group of physicists led by Dr. Kaiser and Alan H. Guth, also at M.I.T., to attempt an experiment that will have a better chance of ensuring the complete independence of the measurement detectors by gathering light from distant objects on different sides of the galaxy next year, and then going a step further by capturing the light from objects known as quasars near the edge of the universe in 2017 and 2018."
--CuriousMind01 (talk) 13:56, 22 October 2015 (UTC)

## I'm probably missing something, but your Bell's inequality seems wrong

$1+\rho_{BC} \geq |\rho_{AB} - \rho_{AC}|$

Replacing B by c, C by b, and A by a:

$1+\rho_{cb} \geq |\rho_{ac} - \rho_{ab}|$

It seems you are missing the absolute value sign.--Guy vandegrift (talk) 04:03, 6 September 2015 (UTC)

On one hand, that is all the same. From $\forall a,b,c \;\; \rho(a,c)-\rho(a,b) \le 1+\rho(b,c)$ it follows that also $\rho(a,b)-\rho(a,c) \le 1+\rho(b,c)$ and therefore $|\rho(a,c)-\rho(a,b)| \le 1+\rho(b,c).$
On the other hand, indeed, the absolute value appears in Bell's original text, equation (15) there; why not do the same in this article? Boris Tsirelson (talk) 19:15, 6 September 2015 (UTC)
Anyway, Mermin's form is rather $0.5(1-\rho(a,c)) \le 0.5(1-\rho(a,b)) + 0.5(1-\rho(b,c)),$ that is, $\rho(a,b)+\rho(b,c) \le 1+\rho(a,c).$ Boris Tsirelson (talk) 19:37, 6 September 2015 (UTC)
Since you don't need the minus sign, you removed it. But removing the absolute value sign weakens the result and also confuses the reader who is looking for it. Before I read a paper, I scan the equations to see what the paper is about. Removing the minus sign interferes with that initial assessment of whether or not I need to read the article. BTW, I am drafting a simple derivation on Wikiversity at v:Bell's theorem/Guy vandegrift. You are welcome to join in.--Guy vandegrift (talk) 09:28, 7 September 2015 (UTC)
The inequality with absolute value sign is two inequalities, depending on whether the thing we take the absolute value of is positive or negative. Those two inequalities are actually (from a mathematician's point of view) the same inequality - prove one, and you have proved the other too, by symmetry. The inequality without the absolute value sign is the one which you need to understand and it is the one with the simplest proof. But actually the CHSH inequality is just as simple to prove and it implies Bell's original and it is the one actually used in experiments. So I recommend you look for a simple proof of CHSH. We know that this inequality is very fundamental, for instance from Fine's theorem which says that one can come up with a local hidden variables model for an experiment with two parties, each with two settings, for measurements each with two outcomes, if and only if the probabilities P(A, B| a, b) satisfy all 8 CHSH inequalities (apply the obvious symmetries to transform one CHSH inequality into others). My favourite proof is the one on my slide 7 of my slides http://www.slideshare.net/gill1109/epidemiology-meets-quantum-statistics-causality-and-bells-theorem Richard Gill (talk) 19:47, 7 September 2015 (UTC)
Wow, that was easy! I will use it at Wikiversity:Bell's theorem/Inequality (but not till Thanksgiving when I have another few days to do as I please).--Guy vandegrift (talk) 03:47, 8 September 2015 (UTC)
No, thanks, I do not join in, for two reasons. First, I already did my best elsewhere. Second, one may write down a lot of various necessary conditions, but they are at best of historical interest, since we know the necessary and sufficient conditions: Bell-CHSH inequalities. All necessary conditions follow from Bell-CHSH. Boris Tsirelson (talk) 10:45, 7 September 2015 (UTC)
I will look at your website. FYI - I just found an extremely simple proof in a textbook by Griffiths. http://www.physics.umd.edu/courses/Phys270/Jenkins/Griffiths_EPR_BellInequality_Excerpt.pdf --Guy vandegrift (talk) 16:37, 7 September 2015 (UTC)
Your link seems not to work. Martin Hogbin (talk) 17:14, 7 September 2015 (UTC)
Try the link now. I had the signature touching the file: ..._Excerpt.pdf--(signature)--Guy vandegrift (talk) 03:17, 8 September 2015 (UTC)

## Sister links to Commons categories

I created a category in Commons, not knowing exactly what I was doing. When I went to put a sister link here, I discovered that you already have one. I presume that you don't want two such links and I presume this is resolved by using subcategories at Commons. I will post the question on commons and place a link here so you can verify the status. If anybody knows how commons does categories, let me know. You may remove the link to the Bell's theorem category if you wish (obviously). See this post on commons.--Guy vandegrift (talk) 23:04, 15 September 2015 (UTC)

The category on commons seems OK. See c:Category:Bell's theorem. You can add or not add. I will move on to other projects. --Guy vandegrift (talk) 01:26, 16 September 2015 (UTC)

## Delete new section "Alternative Analysis"?

I question the recent addition of the section Bell's_theorem#Alternative_analysis. It certainly needs to be stated that papers have been published in refereed journals suggesting that Bell's theorem experiments are flawed. But keep in mind that an experiment demonstrating that nature never violates Bell's inequality would be the greatest event in the history of quantum mechanics. In the minds of most, the only question is whether experiments to verify the violation of the inequality have minor flaws that need to removed before we have (almost) refutable evidence that nature can violate Bell's inequality.--Guy vandegrift (talk) 22:46, 2 October 2015 (UTC)

### 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]
1. ^ Bell, John (1964). "On the Einstein Podolsky Rosen Paradox" (PDF). Physics 1 (3): 195–200.
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]
1. ^ Jaynes, E.T. (1989). 'Clearing up mysteries – the original goal, pp. 1–24 in Maximum Entropy and Bayesian Methods, edited by J. Skilling, Kluwer Academic Publishers, Dordrecht, ISBN 0-7923-0224-9, (a talk given by Jaynes at the eighth MaxEnt Workshop, held at St John's College, Cambridge UK, August 1–5, 1988, a copy of which was kindly supplied to me by Professor Jaynes' secretary while Professor Jaynes was still alive), particularly the section headed 'The Bell inequalities' on pp. 10–12.
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]
1. ^ Khrennikov, A. (2015). CHSH inequalities: Quantum probabilities as classical conditional probabilities, Foundations of Physics, 45: 711–725.
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)

#### ___

Partially offtopic... There is no problem to work with conditional probabilities in Bell's framework. This was made many times. But it was still assumed that Bob's input cannot influence Alice's hidden variables (in contrast to Khrennikov). In fact, I did once such conditional-probability reformulation in the quantum framework, in my work that is justly forgotten,
It seems evident that the immediately foregoing was left incomplete. It was written on this occasion by Editor User:Tsirel.
With much respect for Editor User:Tsirel's opinion, I differ. At present, I think Khrennikov does not, repeat not, think, or use an assumption, "that Bob's input can influence Alice's hidden variables". Perhaps Editor Tsirel may very kindly, if he has time and inclination, say more here that may persuade me that Khrennikov does endorse and make use of that idea. It is conceivable that Editor Tsirel thinks that Khrennikov uses such action at a distance because Khrennikov regrettably uses the very risky and unreliable word 'context' in the present context. Indeed that word 'context', in the present context, is sometimes defined to include an assumption of such action at a distance. But Khrennikov points out the risks of using the word, and he says he is defining it himself for the present purposes, not following the definitions of others. It is a pity that words can be appropriated by factions in the way that has befallen 'contextuality', and I think Khrennikov made a regrettable mistake in letting himself be lured into using the word 'context' in the present context. But I think Khrennikov's argument does not depend on the use of the word 'context', and that Khrennikov's argument does not assume or suggest an assumption of such action at a distance as is implied in in the words "that Bob's input can influence Alice's hidden variables".Chjoaygame (talk) 15:06, 13 October 2015 (UTC)

### ___

────────────────────────────────────────────────────────────────────────────────────────────────────Whatever this conversation is about, it is far too complicated for Wikipedia. Bell's theorem is breathtakingly simple. One could go on and on about what the assumptions mean -- they are hidden variables and that's all the reader needs to know in this article. Other ideas belong in a different article.--Guy vandegrift (talk) 19:17, 3 October 2015 (UTC)

With respect, Guy vandegrift, this conversation intends to consider the proposal that Bell's theorem is not just breathtakingly simple. This conversation intends to consider a paper that means that Bell's theorem is a gross and intolerable oversimplification . There is no suggestion by me or by Khrennikov that there are 'hidden variables'. I, and I think Khrennikov, fully accept quantum mechanics. The present point is rather that Bell's physical assumptions are irrelevant because they are treated wrongly in logic for the crucial delayed-choice protocol.Chjoaygame (talk) 19:41, 3 October 2015 (UTC)
I am now feeling better. I worked out how to access what I had written.
Thank you for your comment, Editor Tsirel. It calls for several lines of response.
It is appropriate here to remember that an ultimate aim of the Bell industry is to establish that quantum mechanics' success is enough to overthrow the idea of causality, and in effect to establish instead a kind of action at a distance, for some cases. Of course, when it is put like that, there is clever word-play to evade the starker implications. Nevertheless, the stakes are high. The standards of reasoning need to be correspondingly high. By such criteria, Bell's derivation fails in logic to deal with what he recognizes as the crucial case, the delayed-choice protocol.
The Bell industry, represented for example by the present Wikipedia article, has set up a special ad hoc vocabulary. Examples of that are in your words 'contextuality' and 'hidden variables'. I think Khrennikov works in a different way. Though he mentions it, he does not mainly rely on a special ad hoc vocabulary, but instead he relies on ordinary mainstream mathematics and logic. I think the special ad hoc vocabulary has been invented for lack of adequate attention to to the need for ordinary mainstream mathematics and logic. What Khrennikov has done ought to have been done forty or even fifty years ago.
Bell's derivation uses probabilistic reasoning that does not condition on the last-moment choices of analyzer setting. We can say this, not only because it is not there in Bell's text, but also because Bell refers to the delayed-choice protocol only in the very last paragraph of his 1964 paper. This means that Bell's derivation cannot refer to experiments of which interpretation needs to rely on delayed-choice reasoning. Khrennikov proposes that for such experiments, explicit account needs to be taken, in the probabilistic reasoning, of the fact that choice means unpredictability, which is mathematically represented as stochasticity; this calls for conditional probability, which is absent from Bell's derivation. I think that talk in terms of 'contextuality', 'hidden variables', and suchlike, is using a special vocabulary that obscures rather than clarifies. I prefer Khrennikov's direct talk in terms of established mainstream probability theory. I think Khrennikov's way makes the logic safer and clearer.
Be that as it may, a more cogent concern here is your question about reliable sourcing and notability. I am no Wikilawyer. My instinct is that if the Khrennikov paper were reliably sourced, then it would well and truly pass the notability test, because it works through ordinary mainstream mathematics and logic, not relying on the special ad hoc vocabulary. More questionable is whether the Khrennikov paper is by itself a reliable source. I think one could well argue that it is primary research, not yet supported or rejected by secondary sourcing, and this would make it inadmissible on the grounds of lack of reliable sourcing. But I am no Wikilawyer and so I will not try to decide that issue by myself.
Perhaps other editors may have opinions here.Chjoaygame (talk) 19:44, 3 October 2015 (UTC)
I see. Well, now I have nothing to say. We appear to think so much differently that our discussion degenerates. It remains to me only to join your last phrase: Perhaps other editors may have opinions here. Boris Tsirelson (talk) 19:54, 3 October 2015 (UTC)
Thank you for this comment. I now reply to your just previous one. I think that there are no such things as hidden variables, and so no thought arises of their being influenced or not influenced at a distance. I think Khrennikov's reasoning avoids entanglement with such ideas, even if he mentions them. The key here is that Khrennikov's method removes putative grounds for a belief that quantum mechanics somehow licenses a sort of action at a distance that is exhibited in the Bell experiments. The experiments are valid, but, when properly interpreted, they do not support ideas of action at a distance. Yes, we will see what others might say.Chjoaygame (talk) 20:04, 3 October 2015 (UTC)
Strangely or not, this time I nearly agree: The experiments are valid, but, when properly interpreted, they do not support ideas of action at a distance; rather, they disprove counterfactual definiteness. In fact, I've voiced this opinion here. Boris Tsirelson (talk) 20:55, 3 October 2015 (UTC)
Yes. Counterfactual definiteness is a metaphysical position. It holds that definite prediction is possible because of a sufficiently deterministic world. Counterfactual definiteness does not hold for phenomena for knowledge of which one needs essentially quantum techniques. In other words, in general, the result of an observation of a quantum phenomenon is not predictable. Perhaps I am mistaken, but I think we know that without needing to rely on Bell experiments? It is evident in the Heisenberg uncertainty principle? But yes, Bell experiments exhibit quantum unpredictability.
Please excuse my edit conflict whinge! I was tired, and I was not familiar with the editing resources of my machine! I soon learnt how to do it.Chjoaygame (talk) 21:31, 3 October 2015 (UTC)
I'd say, quantum mechanics gives us
• predictions;
• point of view.
Accordingly, a physicist can
• be happy with the predictions and the point of view;
• be shocked by the point of view but accept the predictions;
• be shocked by the point of view and hope that some "outrageous" predictions are wrong.
It seems, you belong to the first group (happy with the predictions and the point of view). Indeed, you write "It is evident in the Heisenberg uncertainty principle?" etc. That is OK, of course. But then, what do you seek on this page?? Bell theorem means nothing for the first group. Just work in the quantum mechanics, do the calculations and be happy. Bell theorem is of interest for the shocked. Boris Tsirelson (talk) 05:44, 4 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]
1. ^ Einstein, A.; Podolsky, B.; Rosen, N. (1935). "Can Quantum-Mechanical Description of Physical Reality Be Considered Complete?". Physical Review 47 (10): 777–780. Bibcode:1935PhRv...47..777E. doi:10.1103/PhysRev.47.777.
2. ^ "The debate whether Quantum Mechanics is a complete theory and probabilities have a non-epistemic character (i.e. nature is intrinsically probabilistic) or whether it is a statistical approximation of a deterministic theory and probabilities are due to our ignorance of some parameters (i.e. they are epistemic) dates to the beginning of the theory itself". See: arXiv:quant-ph/0701071v1 12 Jan 2007
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]
1. ^ Khrennikov, A. (2009). Contextual Approach to Quantum Formalism, Springer, ISBN 978-1-4020-9592-4, p. 171 .
2. ^ Kolmogorov, A.N.(1933/1956). Foundations of the Theory of Probability, translated from Russian to English by N. Morrison, second English edition, Chelsea, New York, p. 9.
3. ^ Jeffreys, H. (1939). Theory of Probability, Oxford University Press, Oxford UK.
4. ^ Jaynes, E. T. (2003) Probability Theory: The Logic of Science, Cambridge University Press, ISBN 978-0521592710
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]
1. ^ Khrennikov, A. (2009). Contextual Approach to Quantum Formalism, Springer, ISBN 978-1-4020-9592-4, p. xi.

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)

## The Born rule

The Born rule is usually introduced for an experiment with a very feeble beam with detectors arranged so that only one will click at a given time, indicating the presence of a single particle in a single output channel of the several output channels of a quantum analyzer (for example a Stern—Gerlach apparatus). Such channels, all outputs from a single quantum analyzer, are mutually compatible. If other analyzers are in the set-up, for other particles of the system, they can be chosen in various ways, by an external agent. Those chosen ways should be listed in the statement of the experimental result. The choice of the analyzers is not ordinarily described by the Schrödinger equation. It is in some respects analogous to a thermodynamic operation, not part of the usually considered internal dynamics of the system. This needs to be taken into account for Bell experiments with a delayed-choice protocol, which are crucial for the Bell reasoning. The Born rule then needs to be stated so as to account for the coexistence of the several analyzers.Chjoaygame (talk) 19:03, 11 October 2015 (UTC)

Surely, the Born rule is intended for very simple, highly idealized experiments. In less simple cases, I'd say, we have two ways: (a) include all relevant macroscopic apparatus into the quantum system and then apply the Born rule to an (unproblematic) "secondary" measurement of the outcomes of these (fully decohered) macroscopic apparatus; or (b) use quantum operations and quantum instruments. Hopefully now I use the Latin "apparatus" better. :-) Boris Tsirelson (talk) 19:23, 11 October 2015 (UTC)
My intention was to be vague. I just wanted to note that with several detectors, as in the Bell experiments, the simplest version of the Born rule needs to be suitably upgraded, not intending to say how that should be done.
My present understanding of the Born rule in its usual simple form is that it refers to the probability of detection of a particle by a detector sitting in an output channel of a single quantum analyzer. For example, a detector in an output channel of a polarizing beam splitter. I imagine more complicated cases of several particles in the system, with several analyzers (with their respective detectors), one for each species of particle, for example. At least that seems to be how they do Bell experiments. For this purpose, I don't envisage considering the analyzers as other than, for example, several macroscopic polarizing beam splitters; not treating them as internal parts of the quantum mechanical system and trying to describe them through their contributions to the Schrödinger equation of the system. I am not familiar with talk of 'quantum operations', but it would make good sense, I guess, to say that switching the orientation of a polarizer is a 'quantum operation'?
Looking at the articles you link, I see that the terms 'quantum operation' and 'quantum instrument' have been pre-empted, and defined in more or less abstract mathematical terms that hide or avoid or elide the simple physical kind of meaning I have in mind. Khrennikov has a footnote: "The quantum formalism does not account this sort of randomness. Random generators used in the experimental tests based on the Bell-type inequalities are not described by operators in the complex Hilbert space. They are considered as “technicalities”; often this sort of randomness is related to the freewill of an experimentalist."[1] My guess is that it is beneath the dignity of quantum theory to talk about such practicalities. Some very careful thermodynamic texts (e.g. Tisza) talk deliberately and explicitly about thermodynamic operations in the sense that I mean here. They are essential to a logical treatment of macroscopic thermodynamics.
1. ^ Khrennikov, A. (2015). Found. Phys. (2015) 45: 711–725.
If one really wants to emphasize that one is talking about several distinct devices, I think it is natural enough to treat the word as English and to write 'apparatuses', but others might disagree.Chjoaygame (talk) 21:44, 11 October 2015 (UTC)Chjoaygame (talk) 22:16, 11 October 2015 (UTC)
Do you really mean "thermodynamics" rather than "statistical mechanics"? Why?
About "beneath the dignity of quantum theory", this is up to you. If you can unite all the physics into a single consistent all-embracing theory able to analyze real-life experiments out of the first principles without drastic simplifications, just do it, urgently. :-)
As far as I know, use of temperature and other thermodynamical variables in relation to quantum measurement theory, as inherently classical variables, started in 1960:
H. Wakita, "Measurement in quantum mechanics", Prog. Theor. Phys. 23, 32-40 (1960);
A. Daneri, A. Loinger, G. Prosperi, "Quantum theory of measurement and ergodicity conditions", Nucl. Phys. 33, 297-319 (1962).
(Refs taken from Khalfin & Tsirelson 1992, see [52] and [244] there; also [53]. Mentioned on pages 901 and 905 there.)
Boris Tsirelson (talk) 05:53, 12 October 2015 (UTC)
I was not seeking there to cover a major area of physics, or to settle a deep question. I just intended to say that, in accounts of Bell practical experiments, the switching of the orientation of the polarizing beam splitter is not usually considered as a dynamical process described by the Schrödinger equation. Macroscopic thermodynamics is no more here than an instance of a subject where there is an explicit distinction between the internal adventures of the system (the process), on the one hand, and things that are done to it from the outside (the operation), on the other, but how that difference is carried out is not discussed in detail.
As I think about it, the following question comes to my mind. Allowing unprejudged in logic the contemplation of the possibility that the delayed-choice setting of the orientation of the polarizing beam splitter might affect the result, should one properly include the beam splitter as a component of the quantum system and put its dynamics into the Schrödinger equation for the system? I guess that might have been what you had in mind in a comment you made just above? If, following the orthodox view, one defines one's 'system' as separate from one's 'observational apparatus', and then inquires as to the 'effect' of a delayed-choice orientation switch, has one not moved the goal-posts while the ball is in flight, changed the rules of the game in the middle of play? Is that permitted in soccer?Chjoaygame (talk) 08:52, 12 October 2015 (UTC)
But wait. Bell theorem does not need quantum theory to be correct (correctly used) at all. All we need from quantum theory is advice, how to arrange experiment that will give CSHS>2. After successful experiment of this kind, even compete collapse of the quantum theory would not harm Bell theorem. Thus I wonder, what do you really want to say. Boris Tsirelson (talk) 11:17, 12 October 2015 (UTC)
Ah, no, there is a problem, The real experiment differs from the thought experiment. In the thought experiment, Alice is on the Earth, while Bob is on the Moon. They have some seconds to exercise their free will. In the real experiment, we are asked to believe in some apparatus, that it is indeed nothing but classical randomizers. Yes, clearly a loophole. Boris Tsirelson (talk) 11:27, 12 October 2015 (UTC)
I'm not working from a well-thought-out plan here, I'm just feeling my way. The CHSH inequalities involve several different expectations, that each rely on random polarizer settings. Are we dealing with a single experiment on one singlet system, or with several incompatible experiments on differently tested singlet systems? How do these various items fit into a single probabilistic and physical scheme?Chjoaygame (talk) 12:01, 12 October 2015 (UTC)
Each singlet is prepared, measured once, and lost (destroyed). This happens many times, with randomly chosen settings. Thus, we accumulate statistics for the four cases (2x2=4 settings); these cases get different sample sizes, but all four sizes are reasonably large. Now we calculate the four approximate probabilities, and finally, calculate CHSH. Well, in addition we probably calculate also confidence interval or something like that. Boris Tsirelson (talk) 12:54, 12 October 2015 (UTC)
Or maybe not; really, I never checked, since asymptotically, for large n, it is all the same. Maybe we treat each outcome as "win" or "loss" in the game (randomization of the inputs is the part of the game), and then calculate the approximate wining probability; if it clearly exceeds 0.75, we get excited... Boris Tsirelson (talk) 13:00, 12 October 2015 (UTC)
By the way, the game form of CSHS appears in "Quantum nonlocality". Boris Tsirelson (talk) 16:48, 12 October 2015 (UTC)
We are thinking of a 'classical' scheme when we intend to derive the Bell and congener inequalities. 'Classical' schemes are deterministic and admit neither randomizers nor random experimental results. Classical physics does not admit that Alice or Bob has free will. So I think we are blocked from the very beginning from our intention to carry out the Bell derivation as an example of a classical scheme. Only quantum physics admits random physical processes. An assumption of free will is already a huge metaphysical leap of faith. The existence of randomizers is another metaphysical leap. Assuming these things, it it no surprise that we can then overthrow causality. Our argument has assumed that it doesn't hold.
Classical physics assumes continuity, while the Bell and congener inequalities assume discontinuity. No wonder the consequences of the Bell assumptions rule out classical causality.Chjoaygame (talk) 20:13, 12 October 2015 (UTC)
Not so simple. Classical physics is not only classical mechanics but also classical statistical physics. Molecular chaos is a huge reservoir of pseudo-randomness that is the same as randomness for all practical purposes. This is the harmony between determinism and free will in classical physics. In quantum physics this harmony is broken, and now Gerard 't Hooft is brave enough for rejecting free will; see "'t Hooft's views" in Talk:Superdeterminism. Boris Tsirelson (talk) 20:30, 12 October 2015 (UTC)
Starting from your link to Talk:Superdeterminism, I followed some further links. I reached the following in the article Hard problem of consciousness:

Consciousness is fundamental or elusive

Some philosophers, including David Chalmers and Alfred North Whitehead, argue that conscious experience is a fundamental constituent of the universe, a form of panpsychism sometimes referred to as panexperientialism.

This is a fine example of the misleading effect of the regrettable custom of inventing terms that end in '-ism', and conducting further discussion in those terms . For this example, one can easily understand how the writer reached his statement, and how it might be seen as accurate, assuming his '-ism' mind-set. But the overall effect of his statement is almost to make black into white. The expression 'Chinese whispers' comes to mind. Each step of '-ism' talk leads a little further into muddle, with near-nonsense the eventual outcome. (Of course, I hardly need say that '-ism'-ism intends to be "quick and efficient".) I will likely try to chat more, but not, I think, right here and now.Chjoaygame (talk) 06:31, 13 October 2015 (UTC)
##### Question from Martin

Chjoaygame, can your argument be summarised by saying that, in classical mechanics (without giving humans some special properties outide known physics) nothing can be truly random. Things can be chaotic or pseudorandom but ultimatley, in classical mechanics, everything is fundamentally deterministic. On this basis, because the two random number generators are not truly random, and share the same ancestry, so to speak, a greater than expected correlation between spacelike separated events is possible in classical mechanics? Martin Hogbin (talk) 15:33, 13 October 2015 (UTC)

(This anxiety is often called "conspiracy".) Boris Tsirelson (talk) 15:54, 13 October 2015 (UTC)
Yes, thanks for reminding me of that. We did briefly talk about it before, it is one of the ways out of the EPR/Bell problem that people do not like very much. I have not had time to study the Khrennikov paper properly so I was just taking a stab in the dark. Martin Hogbin (talk) 17:31, 13 October 2015 (UTC)
Basic rule of life: when wondering whether something is due to conspiracy or mistake, go for mistake every time!!Chjoaygame (talk) 16:20, 13 October 2015 (UTC)
I guess you asked a fair question, but, no, Editor Martin Hogbin, that's not, repeat not, my argument here. Far from it. My argument here is: the fact that the orientation of the polarizing beam splitter is changed in some effectively random way needs to be taken account of in the calculations. The result of the calculations depends on whether or not the orientation was moved. It doesn't matter why or how it is moved, but it is an unpredictable thing and that unpredictability is part of the randomness of the experiment.Chjoaygame (talk) 16:27, 13 October 2015 (UTC)
Thanks for your reply. I will carry on thinking about the problem. Martin Hogbin (talk) 17:31, 13 October 2015 (UTC)
I agree that it seems to call for some thinking. It occurred to me this evening as follows. Would an equivalent to the delayed-choice analyzer-rotation protocol be as follows? One of the twin photons passes though a randomized beam deflector. The deflector passes the photon either to analyzer a or to analyzer b, both at the same station number 1. Come think of it, it seems to come to mind that indeed that's how the Bell experiment is sometimes done? Instead of randomly rotating one analyzer, the equipment randomly sends the photon to one of two relatively rotated fixed-orientation analyzers. Now there are four detectors for the station 1 that has the delayed-choice between two analyzers. Two detectors for the station 2 that has only one analyzer, with a fixed orientation. Six detectors altogether. Provided the beam is very feeble, only one of the four choice-side (station 1) detectors will click at the time of clicking of one of the two fixed-orientation detectors. I think this makes it easier to see why the delayed-choice protocol needs probabilistic analysis different from that for the no-switch protocol.Chjoaygame (talk) 18:57, 13 October 2015 (UTC)

## Superdeterminism - "Least" popular?

I really like your lede, which I only just now read because in the past I was combing for calculations. But this sentence bothers me:

Bell summarized one of the least popular ways to address the theorem, superdeterminism, in a 1985 BBC Radio interview:

I am not claiming that this is a "popular" way to address the theorem, but that no view is "popular". The statement in question seems to imply that popular views exist. It also implies that scientists disfavor this view when I think they are sublimely neutral to it. I think the most common view among experts is bewilderment that ranges from mild to extreme. I don't think any philosophical view is "popular", except perhaps that looking for a hidden variable theory is a waste of time. If people agree, then we can look for a subtle change in the wording. Perhaps this:

Bell summarized one of the more obscure ways to address the theorem, superdeterminism, in a 1985 BBC Radio interview:

In conclusion, the phrase "least popular" carries the connotation of "disliked". Personally, I found this view fascinating for a few days, and then decided to live the rest of my life as if I had free will-Guy vandegrift (talk) 14:19, 19 October 2015 (UTC)

I even thought about creating a one-dimensional universe with a big bang that consists of N identical non-interacting pairs of entangled particles travelling at different speeds (with Gaussian probability for position/momentum, centered spatially at the origin). The initial orientation of the observing filters would be predetermined, but the outcome of each measurement would determine the next measurement's orientation. This would be a trivial but tedious problem to solve, made complicated by the possibility of the "slow" particles arriving at the detector before the "fast" ones did. Sounds like a nice project for a gifted young student, but not worthwhile for an adult.--Guy vandegrift (talk) 14:33, 19 October 2015 (UTC)

I do not think we should editorialise in this manner at all. We should write:

Bell summarized one way to address the theorem, superdeterminism, in a 1985 BBC Radio interview:

Martin Hogbin (talk) 18:59, 19 October 2015 (UTC)

I agree. Strictly speaking, we shouldn't say "obscure" unless a source labels it as somehow "less popular" (if there is such a source, I'm certain the author meant "less common" instead of "less will-liked"). Feel free to change it. I am a Wikiversity writer and avoid editing WP whenever possible.--Guy vandegrift (talk) 19:16, 19 October 2015 (UTC)
Not sure about source, but it seems to me that it EVIDENTLY is MUCH less popular. Look for example at articles about games using entangled states. Almost all authors call them "nonlocal games", "nonlocal strategies" etc. So much so, that I, in my Citizendium article, was forced to emphasize that there are three principal assumptions, and locality is one ("first") of them, but there is also "second" (my pet), and, well, "third". Last years the third one is taken seriously by 't Hooft; and is discussed, after him, by several other authors. I do not know the future, but for now still most physicists did not hear about "second" and, the more so, "third" option. Boris Tsirelson (talk) 19:25, 19 October 2015 (UTC)
Sorry, I changed it before I read this. Martin Hogbin (talk) 19:35, 19 October 2015 (UTC)
Could we say something more specific like 'least studied'. Of couse that is because it is beyond the scope of physics but it is at least an indisputable fact. Martin Hogbin (talk) 19:37, 19 October 2015 (UTC)
According to 't Hooft, it is not "beyond the scope of physics". But for now he still has few followers. And, I guess, Richard Gill will claim (with sources) that Bell did not take the third option seriously. (I remember he did already.) Boris Tsirelson (talk) 19:43, 19 October 2015 (UTC)
More information about 't Hooft and superdeterminism may be found in archived discussion here: Wikipedia:Dispute_resolution_noticeboard/Archive_123#Superdeterminism. Boris Tsirelson (talk) 19:52, 19 October 2015 (UTC)
No, even better, this discussion: Wikipedia:Articles_for_deletion/Superdeterminism. Boris Tsirelson (talk) 19:55, 19 October 2015 (UTC)
I do not think that 't Hooft he says that superdeterminism is not beyond the scope of physics, he says, ' The definition usually employed is clearly invalid in strictly deterministic theories' and then he propses an alternative model of free will. He does not say that 'The definition usually employed' is within the scope of physics.
Anyway, if we put something clearly factual like 'least studied' ther is no need to discuss this point. Martin Hogbin (talk) 21:26, 19 October 2015 (UTC)

──────────────────────────────────────────────────────────────────────────────────────────────────── I reverted back to referring to superdeterminism as "one of the least popular ways" because no consensus has been reached. Bell himself refered to it as implausible, and Boris Tsirelson gave evidence. My suggestion was not that we change the meaning of the sentence, but merely the word chosen to convey that meaning. "Unpopular" when referring to humans means annoying or lacking friends. The word just had too many connotations for me, and I though "obscure" was better suited.--Guy vandegrift (talk) 09:54, 20 October 2015 (UTC)

## Confusing terminology

For a start, can anyone put them in order of 'hardness'.

Is there agreement on the correct term for the philosophy that the future of the universe and everything in it, including human actions and though is absolutely fixed and immutable?

In Bell's statement, '...absolute determinism in the universe, the complete absence of free will. Suppose the world is super-deterministic, with not just inanimate nature running on behind-the-scenes clockwork, but with our behavior, including our belief that we are free to choose to do one experiment rather than another, absolutely predetermined, including the ‘decision’ by the experimenter to carry out one set of measurements rather than another,...',which of the above is he referring to? Martin Hogbin (talk) 21:46, 19 October 2015 (UTC)

As I stated above, I like this lede. The boxes put me off as I skimmed it because I thought they were attempts at rigorous definition. Instead they are well-known attempts to explain the unexplainable. Not all these people chose the right words, or they might have chosen the right words at a time or place when these words carried different connotations. Bell was speaking in a radio interview when he used the words "implausible" and "superdeterminism". Did Bell publish any papers on the subject?--Guy vandegrift (talk) 10:16, 20 October 2015 (UTC)
On Wikiversity, where it is the custom to start a parallel article instead of editing the writing of others, I replaced the content of this article's lede by one sentence: Bell's theorem has no more business than sunsets and sunrises to be paradoxical. It conveys the wide range of views one can legitimately take, and is sort of a portmanteau of comments by Marmin and Tovey. --Guy vandegrift (talk) 10:26, 20 October 2015 (UTC)
I can't rank in order of "hardness", but I now understand the lede: Bell was was looking for a theory to replace Quantum mechanics in which variables "existed" before they were measured. He characterized his "superdeterminism" as "implausible", and the idea is "not popular" for good reason. In this scenario, the universe is a gigantic "clock" in which all the variables are predetermined to obey what we know as quantum mechanics. The same initial conditions that caused the polarization of an entangled photon to lie in a given direction also cause the humans to construct the experiment to measure that photon's polarization along that prescribed direction. It is a clock where the behavior of every single atom was choreographed from the beginning. It was implausible to Bell and not popular in the eyes of the editors of this article. The phrase "one of the least popular" should stand, IMHO. previous comment by same user was stricken--Guy vandegrift (talk) 14:25, 21 October 2015 (UTC)
What meaning do you intend to convey my the word 'unpopular'? Do you mean that it is not studied by physicist much (if at all)? If so then I agree with you, but why not state that fact more clearly. Do you mean that physicists, or mathematicians, or the public at large find the idea umpalatable or disturbing? If so who says this? Did Bell dislike this idea? Does 'unpopular' refer just to the editors of this article. If so, in my opinion it is unjustified and vague editorialising. Words like 'implausible' do not have any meaning in this context.
I know perfectly well what Bell meant. Exactly as you say, the universe is an already-written and immutable book. That philosphy is a very ancient idea that has been discussed for centuries. The generally opinion on the subject is that there is no conceivable way of testing the idea experimentally; it is a logical impossibility in that, whatever results may be obtained from whatever experiment it is always possible to say, 'that is what was ordained'. For that reason Bell's superdeterminism (or whatever we agree to call it) lies outside the scope of physics is therefore, by definition. 'unpopular' with physicists.
My dictionary defines 'determinism' as 'the philosophical doctrine that all events, including human actions and choices, are fully determined by preceeding events and states of affaires, so that freedom of choice is illusory'. This seems to me to be what Bell meant. In order to get some experimentally testable predictions many people seem to have 'softened' the meaning of some of the the various words for this concept so that we now need to invent new ones for the original idea. Martin Hogbin (talk) 15:18, 21 October 2015 (UTC)
As I stated when I re-introduced this discussion of the lede, I am concerned with the connotations associated with the word "least popular". I agree with you that "implausible" is not an appropriate word, but it is the word that Bell chose. Also, I am not comfortable with the Bell's mention of free will. I think what Bell was referring to was the extreme sensitivity to initial conditions. I don't know if Bell was thinking about the butterfly effect, but if he was, it's a pretty "implausible" butterfly that can simultaneously change what happens near a detector, and what happens inside the atom that created the entangled particles. We can't edit Bell's words, but perhaps we can come up with a brief paragraph that expresses Bell's sentiments. I know Wikipedia frowns on long footnotes, but I would put Bell's words in a footnote. Personally, I frown on long ledes. As is often the case, I am not entirely comfortable with the lede, but can't think of a better one. One option might be to improve Wikipedia's Superdeterminism. Does the word "superdeterminism" have any meaning outside the context of Bell's interview? I have no idea.
As for the word "superdeterminism", how do you get more deterministic than "deterministic"? I think it's just a superlative prefix that Bell added to emphasize how amazingly implausible a Newtonian "clock" universe would be if it also obeyed quantum mechanics. All this is why I prefer to write in Wikiversity where I am free to express ideas in my own words.
I guess we should put it to a vote. I reverted your edit because I felt responsible for triggering the edit and also felt guilty for raising the question before I managed to understand what the lede was trying to say. If you revert my revert, there will be no edit war from me.--Guy vandegrift (talk) 16:47, 21 October 2015 (UTC)
I am not going to fight about 'unpopular' either. There is a common misconception though that I believe should be dealt with in the article somewhere though, and that is the idea that QM is incompatible with determinism. The odd thing is that it is fully compatible with the most extreme form of determinism (whatever we choose to call that) but lesser forms, in which the actions of inanimate objects are fully deterministic, but humans (and maybe cats?) are able to act in some way independently of the physical world (I think Bell is on record as not liking that possibility much either.) is incompatible with QM. Martin Hogbin (talk) 17:34, 21 October 2015 (UTC)
As long as we think about physics (rather than, say, hard problem of consciousness, philosophical zombie etc.), free will is not really relevant. What is really relevant is, existence of local pseudorandom number generators that are, for all practical purposes, random (and local). In classical physics (mechanics plus statistical physics), such generators are abundant (the so-called molecular chaos). Accordingly, one may well believe that the future is predetermined, but only in principle, while for all practical purposes we have free will. But in quantum physics, this harmony is undermined by Bell theorem. This is the context in which the term "superdeterminism" is used by Gerard 't Hooft and some others. Boris Tsirelson (talk) 17:54, 21 October 2015 (UTC)
Note also that the (very important in physics) Einstein locality principle cannot even be formulated without local randomizers. But it is usually considered true in the classical physics. Think, why... Boris Tsirelson (talk) 17:57, 21 October 2015 (UTC)
The recent ideas of 't Hooft are the first (in the history) attempt to build a physical theory that stipulates the so-called "conspiracy", thus making the determinism (thus, failure of local randomizers and free will) visible "in practice", not only "in principle". If you like: visible to mortals, not only to immortals. Boris Tsirelson (talk) 18:00, 21 October 2015 (UTC)
It is fundamentally impossible to disprove the theory that everything is preordained. 'Random' has no meaning in this model of the world. Whatever the result of any experiment the answer is always that it was already decided. Martin Hogbin (talk) 19:06, 21 October 2015 (UTC)
Yes, I agree. But (a) this fact itself does not imply existence of any meaningful physical theory with "conspiracy"; and (b) the conjecture that everything is preordained is not falsifiable, but its negation is also not falsifiable, which means, it is, forever, a matter of belief. Boris Tsirelson (talk) 19:20, 21 October 2015 (UTC)
That is what I have said all along, I was not sure if you agreed or not. It is purely a matter of belief and is therefore outside the scope of physics. On the other hand it is something that we should make clear in this article, not because it is directly relevant to Bell's theorem but to dispel the common misconception that QM and Bell's theorem experiments can disprove this belief. One of the problems in making this fact clear is the confused terminology that I refer to below. Martin Hogbin (talk) 22:07, 21 October 2015 (UTC)

────────────────────────────────────────────────────────────────────────────────────────────────────Does anybody like the idea of briefly paraphrasing Bell's "superdeterminism" comment and using the link to Wikipedia's article of Superdeterminism? Something like this: In a radio interview Bell introduced what he called superdeterminism as another way to address the theorem. In this scenario the behavior of all particles, including those involved in choosing the measurements is predetermined by initial conditions. This removes the need for faster-than-light communication. Bell himself referred to this idea as "implausible"--Guy vandegrift (talk) 18:18, 21 October 2015 (UTC)

For now, this article is much more professional than "Superdeterminism" (not sure this one will stay professional, but sure, the other one will often be attacked by cranks). Boris Tsirelson (talk) 18:29, 21 October 2015 (UTC)
Apart from making the agreed facts a little clearer here, as I suggest above, I agree that it is the other articles that need improving rather than this one. Whether we can improve those articles is another matter. Even Superdeterminism contains this statement, ' It is conceivable, but arguably unlikely, that someone could exploit this loophole to construct a local hidden variable theory that reproduces the predictions of quantum mechanics'. Superdeterminism is not a theoretical loophole in physics, it is a belief that is outside the scope of physics and cannot therefore be used to construct a theory of physics any more than Christianity can. Martin Hogbin (talk) 22:17, 21 October 2015 (UTC)
As for me, this article is, and should remain, a matter of physics. The other one also should be first of all about physics, namely 't Hooft, but may give more attention to philosophy. For genuine philosophic matters we already have philosophically oriented articles (linked above). Boris Tsirelson (talk) 06:33, 22 October 2015 (UTC)
Also, Martin, we had a discussion on these matters in Dec 2013 - Jan 2014, see archive 6 and archive 7 of this talk page. Anything new now? Any reason to reconsider? Boris Tsirelson (talk) 09:01, 22 October 2015 (UTC)
Yes, there was a rather long discussion, including Richard and others. At one point we had:
I do hope that you understand my point though. Making invalid claims for Bell's theorem brings physics into disrepute and causes people to lose faith in it. Martin Hogbin (talk) 09:52, 2 January 2014 (UTC)
Happy editing. Boris Tsirelson (talk) 12:47, 2 January 2014 (UTC)
So you were not against some clarification then. This also shows my rationale for wanting to clarify things here. I do not think that I actually made any edits to the article at that time as I wanted to work with another editors if posible. Maybe Guy would be interested in working with me on this subject. Martin Hogbin (talk) 10:59, 22 October 2015 (UTC)
You actually made edits yourself on Jan 30: this diff. Boris Tsirelson (talk) 17:28, 22 October 2015 (UTC)
Yes you are correct. Maybe that is enough then, unless anyone else thinks that we need to make it any clearer. Martin Hogbin (talk) 17:47, 22 October 2015 (UTC)
"Making invalid claims brings physics into disrepute" — but I feel it differently. For a reader X that takes physics seriously, the formal logical consistence between facts and superdeterminism is of little importance. Such X is bothered, rather, whether or not the mainstream physical theory (or at least a serious alternative physical theory) supports superdeterminism. And for a reader Y that takes superdeterminism much more serious than physics, physics is already in disrepute anyway. This is why I do not share your concern. Boris Tsirelson (talk) 19:09, 22 October 2015 (UTC)
In other words: reader X hears from physics the voice: "as far as we understand, randomness exists"; and reader Y is attentive to different voice(s). This is the life, and you cannot change it by any edits to physical articles. Boris Tsirelson (talk) 19:47, 22 October 2015 (UTC)
Since you have pointed out that I have already made edits about this subject (which I forgot about) I am happy to leave things as they are and I will not be pushing for further changes. Martin Hogbin (talk) 21:28, 22 October 2015 (UTC)