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  1. editor
    editor at | |

    This paper has been sent out for peer review.

  2. editor
    editor at | |

    Report of Referee B:

    This manuscript is a compelling and enjoyable response to a recent paper by Wiseman. As per usual, Norsen's writing here is clear and precise, and the arguments are very sound. What's more, it's a *useful* argument to make, in that many people do seem to have the same view as Wiseman on this matter, so this is not a paper with a mere audience of one. I strongly recommend publication.

    I only have two recommendations to strengthen the paper, both optional. The first suggestion concerns the introduction of equation (1). I realize that the discussion of this equation does not occur until later in the paper, but it might help clarify the key upcoming issues by explicitly noting that (1) is a definition of locality expressed entirely in terms of probabilities. (This is later stressed on page 6, but might be worth explicitly noting here as well.)

    The other suggestion is that the author could choose to directly take on Wiseman's section 3. On page 1, Norsen notes that "there's a lot going on in Wiseman's paper", and tries to put the focus on Bell 1964, which is all well-and-good. But Wiseman's section 3 purports to be a direct critique of the very view that Norsen is advocating here. So a direct response to this critique would seem to be an appropriate addition.

    After reading this manuscript, I went back and read Wiseman's section 3, and can pretty much imagine what Norsen's direct responses would be, as they've been clearly presented in this manuscript. But perhaps a point-by-point response might be a nice way to frame a summary of the main arguments (or perhaps form an Appendix for those interested?) Again, this is not a crucial addition, as the main points have all been made, but might make this manuscript an even stronger rebuttal to Wiseman's perspective.

  3. editor
    editor at | |

    Report of Referee A:

    This manuscript presents the author's views on Howard Wiseman's paper "The Two Bell's Theorems of John Bell". In my opinion Wiseman's paper is an important attempt at bridging the divide, between what Wiseman calls "realists" and "operationalists", over the meaning of the phrase "Bell's theorem". Hence it may be worthwhile to have on the record the response of a representative "realist", such as the author. Although the author's basic position on the interpretation of Bell's 1964 has been expounded by himself and others many times already, I would say that enough of the present manuscript is sufficiently novel for publication.

    With one glaring exception, the manuscript summarizes Wiseman's position fairly well and insightfully engages with it. Provided that exception is resolved, I am therefore happy to support publication.

    The glaring exception exception is on pages 8 and 9, where two quotes from Wiseman are severely distorted to create what can only be described as a straw man, which is then of course easily knocked down.
    The relevant discussion begins with 'Wiseman's charge that Bell "made a mistake"'. Wiseman indeed makes such a charge. But before long, and for no reason that I can fathom, this becomes 'Wiseman's charge that both Bell and Einstein "made a mistake"'. Calling this 'Wiseman's charge', and using the attributed Wiseman quotation "made a mistake", clearly suggests that Wiseman himself has charged Einstein with a mistake. I have read Wiseman's originally paper carefully, and so can confidently say that he has done no such thing.

    The best solution would be to simply remove this claim in its entirety (that would improve the manuscript since the claim verges on inconsistency with the "Here it worth recalling..." discussion that follows anyway). If the author is absolutely determined to keep it, then an actual justification must be given, making it clear that it is the author's extrapolation from Wiseman's statements rather than anything that Wiseman has actually wrote. The format would be something like this: "Wiseman does not explicitly accuse Einstein of making a similar mistake. But since Wiseman does say x and y, logical argument z says that he must also believe that Einstein has made a mistake." I cannot see any such argument being successful, since it will most likely involve an assumption that Bell and Einstein were using the same "localistic" notion, which Wiseman explicitly disputes.
    But at least the reader will be able to judge the logic for themselves, rather than simply being misled into thinking that Wiseman stated something that he did not.

    The second distortion is the claim that Wiseman believes 'Einstein's "no telepathy" notion of locality "has the same force as local causlity"'. To see the problem here, we need only read Wiseman's full
    sentence: "With some thought, one can propose a strong but reasonable formalisation for ['real factual situation'] such that the assumption (which, prior to the passage quoted above, Einstein makes explicitly) that systems have real factual situations, plus the no telepathy supposition, has the same force as local causality". So much of what Wiseman actually wrote has been expunged from the manuscript's version as to make it a fundamentally different statement, and one that is at odds with Wiseman's actual stated position. Some attempt to repair the damage is done in footnote 5, but this only deals with the "assumption ... that systems have real factual situations" part and not at all with the (much more important for these purposes) "one can propose a strong but reasonable formalisation" part.

    What is the best solution here? My own view is much like the author's view on Bell 1964: "it is notoriously difficult to precisely capture the idea of causal influence in the context of general (not necessarily determinstic) theories. So it is simply not clear how to translate Bell's words here (about locality) into a sharp mathematical statement in terms of which the EPR argument might be rigorously rehearsed". Replace "Bell" with "Einstein" and I couldn't have described the situation better myself! If the author doesn't want to go that far, he should at least quote Wiseman in full and explain any disagreement, again with the aim of giving the reader a fair shot at deciding who's actual position is the correct one.

    With that out of the way, I might as well use this opportunity to offer the author a few suggestions for improving the manuscript in other ways:
    p1-10: The author shares with other "realists" the unfortunate habit of abbreviating "local causality" to "locality", which plays a non-trivial role in "realist"/"operationalist" misunderstandings.
    Whilst I doubt that I can convince him to stop doing this in general, would he at least consider suspending the practice in this particular manuscript, which is after all partly about what different people have used the word "locality" to mean, and responds to a paper that (also unfortunately, in my view) specifically defined "locality" to mean something else? I'm thinking in particular of places where the manuscript speaks of Bell's 1976 paper and the conclusion one can obtain from Bell 1964's paper by combining the mathematics there with the EPR argument, which would be much clearer if the author called "local causality" by its name.
    p1: In "So, according to Wiseman, Bell,...", "according to Wiseman"
    should be bracketed using dashes or parantheses. At the moment Wiseman looks like the first name in the following list.
    p2: The phrasing in "As Wiseman acknowledges, this reading..." is a little mischievous as of course Wiseman does not acknowledge that his reading is in fact a "misunderstanding". How about something like 'As Wiseman acknowledges, this reading puts him in the "almost universal"
    school of interpretation that Bell himself would later take issue with'.
    p2: Using a superscript 2 for Bell's citation of Einstein is a little confusing, especially as there currently happens to be an unrelated footnote 2 in that very column. Perhaps this will be alleviated by the journal's formatting.
    p3: "For the proof of this last claim" - the following phrase does not actually describe a claim. I'm not sure exactly what the author intended, but removing the comma and changing "including" to "include"
    would fix this, as would appending ", can prove determinism".
    p6: "he invites his readers to find in the paper of Einstein" - should this be EPR?
    p8-p9: During the "John Bell Workshop", under the incisive questioning of a certain "Dr. Pusey", the author seemed to acknowledge that Einstein's autobiographical notes only contain a direct argument against ψ-completeness rather than for determinism, and that these "are distinct, though of course closely-related"
    It might be worth tweaking the presentation of Einstein's argument to make these nuances clearer. For example, I don't know if the author still holds that 'Einstein makes _precisely_ the argument that "Bell wants to make"', rather than just a closely-related argument.

  4. editor
    editor at | |

    Author's response:

    First of all, I offer my sincere thanks to the two referees for their careful readings of my paper and for their helpful suggestions.

    Let me first address Referee A’s two major complaints about my paper. The first of these is that I insinuate that Wiseman has charged not only Bell, but also Einstein, with some kind of “mistake”, when Wiseman has in fact charged only Bell, not Einstein, with any mistake. Insofar as one accepts that Bell meant to be rehearsing or recapitulating the earlier Einstein/EPR argument – and insofar as one insists (as Wiseman does) that this part of Bell’s argument is invalid – there does seem to be an implication that the Einstein/EPR argument as such is invalid. And in that case, it would indeed evidently be not only Bell, but also Einstein, who were mistaken in believing the argument to be valid. That, at least, is what I meant to convey in the offending section of the paper.

    But, because I agree with the referee that it is not fair to imply that Wiseman does actually mean to charge Einstein with having made a mistake, I have re-written this part of the paper to remove that implication and instead just explicitly raise what I consider to be the crucial (and essentially unanswerable) questions, about the relationship between Bell’s alleged “mistake” and the Einstein/EPR argument he was there recapitulating, that Wiseman’s interpretation raises.

    Referee A’s second major complaint about my paper has to do with my claim that, according to Wiseman, Einstein’s “no telepathy” notion of locality “has the same force as local causality”. As the Referee points out, Wiseman actually believes that it is only Einstein’s “no telepathy” condition *in conjunction with Einstein’s idea that we can attribute “real factual situations” to systems* that “has the same force as local causality”. By way of explaining my position here, let me quote from a comment I made on Wiseman’s contribution to the IJQF “John Bell Workshop 2014” (namely, Wiseman’s draft response to my paper here):

    begin{quote}I understand that you think it is misleading to suggest that (what you call) "no telepathy" *alone* "has the same force as local causality" since, you want to say, it is really only "no telepathy" *plus* "the assumption ... that systems have real factual situations" which, together, "have the same force as local causality". I agree that this other realism-type assumption is needed. But I think we disagree about the logical-hierarchical relation of the two assumptions. In my view (which is also Einstein's view and Bell's view) "the assumption that systems have real factual situations" is a pre-requisite for discussing locality. That is, one could not maintain a meaningful notion of locality (such as "no telepathy") while rejecting this elementary sort of realism. Indeed, as I pointed out in my comment above, the relevant section of Einstein's Autobiographical Notes begins with a statement about this sort of realism being an essential aspect of what "Physics is". I thus find it quite misleading to list this as an assumption at the same level as locality, as if one could meaningfully choose to maintain *either* (by abandoning the other). You probably disagree with all this. I'm not trying to convince you to agree with me; I'm just explaining why, from my point of view, it is in fact quite accurate to identify Einstein's formulation of locality (from the Autobiographical Notes) with what Bell would later call "local causality". (Note by the way that an identical "realism" assumption underlies Bell's "local causality".)end{quote}

    I have slightly edited the relevant section of my paper (including footnote 5, which explains the situation in a little more detail) but basically I stand by the idea which motivated my omitting any mention of this other (“realist”) supposition. In short, I think it is quite accurate to say (without qualification) that Einstein’s “no telepathy” condition “has the same force as local causality”. And for those who disagree, the desired qualification is there, in the footnote.

    I have made several other minor changes to the paper in response to the Referee’s several suggestions at the end of his report. The Referee is correct, though, that he will not convince me to stop using the word “locality” in the way that annoys him, and my reasons for this are implied in the Referee’s own comments: the Referee thinks that, in 1964, Bell “specifically defined ‘locality’ to mean something else” – other, that is, than the “local causality”-type notion that I mean by “locality”. But surely the Referee understands that here we simply disagree, and that this disagreement is precisely the central issue of my whole paper. I do not think that Bell ever used “locality” to mean Parameter Independence. Instead I think he meant, by “locality”, in 1964, the “no telepathy” condition of Einstein, which (I think) is precisely a (somewhat less formal) version of “local causality”. And if I’m right about that, it would be positively inappropriate (because misleading) to introduce two distinct words for what is, in fact, the same one underlying concept. So I stand by my use of terminology as absolutely required, for accuracy, given the interpretation of Bell’s 1964 paper that I am elaborating in this paper.

    There is, obviously, less to say in response to Referee B. I appreciate (and to some extent sympathize with) the suggestion to note, as soon as Equation (1) first appears, that it is a statement about probabilities and that nothing Bell writes in 1964 (that is, none of the passages that Wiseman regards as the evidence for his interpretation that Bell meant Equation (1) when he wrote “locality”) is about probabilities. My feeling, though, is that in Section 2 of the paper, I am trying to simply summarize Wiseman’s views – before jumping in to dispute/refute them – and it would be somewhat unfair to Wiseman to interject such “sneak peeks” at my later rebuttals. Hopefully readers can be trusted to have the patience to understand Section II as presenting a perspective with which I will ultimately come to (strongly) disagree. I did, however, slightly strengthen the wording when it is pointed out, later, that Equation (1) is about probabilities and therefore cannot represent anything like a direct translation of Bell’s words… just to make sure readers don’t miss this crucial point.

    And then I must confess to being slightly puzzled by the Referee’s suggestion that I should somehow more directly respond to Section 3 of Wiseman’s paper. My whole paper is, in essence, my response to Section 3 of Wiseman’s paper. Of course, if the Referee’s point is just that there are many other small items in Wiseman’s section 3 that I would disagree with, that is correct. But I really did want to stay focused on what I consider the fundamental issues, and not get bogged down in all of the little side issues. My hope is just what the Referee expresses – that, like the Referee, other readers will be able to see for themselves the other various problems with Wiseman’s paper, once they have understood the two fundamental issues: what did Bell mean by locality, and what was the role of the EPR argument in Bell’s overall presentation?

  5. editor
    editor at | |

    Report of Referee A:

    The manuscript is overall significantly improved. In particular, the blanket claim that Wiseman accused Einstein of a mistake has been replaced by a much more careful exploration of the possible relationship between Wiseman's 2014 paper and the Einstein/EPR arguments. However, although the author has also sought to address my objection to the Wiseman quotation on "no telepathy", I still don't think the current discussion does justice to Wiseman's 2014 text.

    To be clear, I would have no objection to the author arguing for (or even just flatly asserting) *his* opinion that 'it is quite accurate to say (without qualification) that Einstein’s “no telepathy”condition “has the same force as local causality”'. My objection is only to the claim that this is opinion is also expressed by Wiseman in his 2014 paper. The footnote deals with the "existence of real situations" subtlety, but not the "with some thought, one can propose a strong but reasonable formalisation" part. The simplest fix would be simply to quote Wiseman's sentence in full, perhaps as a footnote to "acknowledge", which would hardly be a great burden since the manuscript is already contains a number of long quotations.

    Under normal circumstances the fact that this problem is still present would suffice for me to object to the publication of the manuscript. However, there are several special considerations in this case:

    1) A third round of reviewing, regarding a single sentence, would place a disproportionate burden on the author of this manuscript, the authors of the reply, the referees, and of course our editor.

    2) I don't think the author intends to misquote Wiseman. Rather, based on the author's conceptual scheme, the parts of Wiseman's sentence that he has omitted seem unimportant. (Based on my conceptual scheme, the omitted parts are essential.) I also suspect this difference in conceptual schemes is why my first report did not convince the author that Wiseman's whole sentence needs to be quoted, and this report will not either.

    3) Most importantly, I presume that this manuscript will be published alongside the Wiseman/Rieffel reply, which identifies this issue and provides the full quotation from Wiseman's 2014 paper.

    Since the overwhelming majority of the manuscript is interesting and clear, and the considerations above speak against further delay, I support its publication.

    I can't resist throwing in a brief postscript on 'locality' versus 'local causilty'. The author's response suggests that I think "in 1964, Bell “specifically defined ‘locality’ to mean something else”". Actually my "specifically defined 'locality'" remark was aimed only at Wiseman's 2014 paper. I thought we all agreed that, for better or worse, Wiseman's 2014 paper uses the word 'locality' to mean PI. A reader that is attempting to read this manuscript alongside Wiseman's 2014 paper has to keep switching between the different definitions of 'locality' in each context. If our beleaguered reader actually thinks 'locality' in Bell 1964 refers to some third concept, distinct from both PI and local causality, (or simply wants to remain open-minded about Bell's meaning) he would have to juggle three definitions (or two definitions plus one lack of definition)! The suggestion to call local causality by name is only supposed to ease this cognitive burden. This would not prevent the author from arguing, as forcefully as he wishes, that 1964 Bell's use of 'locality' should/must be understood as 'local causality'. Of course a very similar criticism can be levelled at Wiseman's 2014 choice of terminology (and indeed I think Wiseman 2014 would have been clearer had it used PI or some other non-overloaded term), but two wrongs don't make a right!

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