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Sorry, @bangstrom, but now you crossed the border of an honest, argumentative discourse. I assume you have some ideological reasons, and that your ideology needs non-locality. Otherwise I cannot explain the huge misses you make here, and your derogation of Joigus' and Swansonts knowledge of QM. The no-communication theorem is derived from the formalism of QM, and is valid on all levels. If you observe something only one time, you cannot conclude that it has changed. In Bell-like experiments, Bob from his side does not notice anything special. He just gets random results, as if he is just doing experiments on some simple particle source. Only when Alice and Bob compare their lists (these cannot be send FTL), they notice that the correlations are stronger than any classical system allows. On the contrary. The problem is you do not understand modern QM. Einstein objected against the non-local 'odour' of QM, but since then, physicists have developed QM further, and e.g. came up with the no-communication theorem, which excludes any FTL communication (and effect, and influence, and ...). Invalidated? On the contrary, the conclusion of the article that seemed contradictory to relativity, was confirmed by Bell-like experiments: the QM depiction of the world that Einstein thought was too absurd to be true, turns out to be true. And still Zeilinger would rather give up realism than locality. That is clear if you would really read his book, understand his argumentation, instead of citing passages from his book that seem to support your position. Nope. Read, and understand what Zeilinger is saying: in short, if Alice does here measurement before or after Bob did, it describes two different experiments, which means different boundary conditions. As said before, of the five ways Zeilinger mentions that could explain Bell-like experiments, Zeilinger dismisses 'back in time propagation', instead refers, to the fact that they are different experiments. Maybe this has a connection, or is even an example of 'contextuality' as meant in the Kochen-Specker theorem? @joigus: do you think that is correct? So no outrage about the position of Gell-Mann, Susskind, Kracklauer, Sidney Coleman, etc.? In short, you are not able to show an authoritative text, that pleads for giving up locality instead of realism. Sigh... Using 'action' again. 'My experts' disagree with you, and Zeilinger explicitly prefers to give up on realism, instead of locality. I am afraid, you forgot again, that teleportation needs an additional classical communication channel. I think I am done here. Unless a Bell-Kochen-Specker-Bangstrom inequality is derived that can distinguish if we must abandon locality, and not realism, (and empirically tested of course), I rest my case. Your ideological glasses make you blind, blind as two perpendicular oriented polarisators behind each other.

You should better take care of your words, which is very important in such fundamental questions. I made them italic: action: we had this again and again. There is no action, no interaction, no causal relationship, no information transfer, no affect, no influence between the measurements. These are all excluded by the no-communication theorem. change: there is no change, in the first place because a change needs a cause, and that is already done away with with the previous point. In the second place, we cannot detect this change, because we cannot observe the wave function itself. We cannot look deeper then individual quantum measurements, and therefore we can only detect correlations. This is hubris. Swansont knows more about QM than you, me, and Joigus together. You are referring to the mainstream again. And still, you are not able to mention any QM expert precisely arguing why it is that we have to give up locality in QM. Again you do not understand quite what Zeilinger is saying here, and his viewpoint later in the chapter. I italicized the words. Zeilinger does not talk about events 'influencing' events in the past. He is saying that our interpretation of the experiment is different. Alice's measurement occurring before Bob's measurements, or after his measurements are different experiments, i.e. we need different interpretations of the experimental situation. Emphasis by me. And then: And then, more specific: Italics by me. The obvious problem for you is that Zeilinger is a nice and reasonable fellow. So he presents different viewpoints and mentions a few arguments pro and contra these viewpoints. And then you pick out the arguments that fit to your viewpoint. But giving his own viewpoint Zeilinger is very clear: on QM level, we have to depart from realism; not locality. I showed you above that this is not his opinion. And you are using 'action' again! Underlined it for you. Sure, he does not say this is excluded, but that giving our present insights it is not the best solution, because it would mean a total rewriting our present understanding. It is also, clear from the context in which he discusses this, taking the options 4 and 5 behind the sentence: Meaning 'to be honest, there are two other interpretations, but I do not take them seriously'. You really have a problem understanding texts.

With a single particle, entanglement of course plays no role at all. Which is what Zeilinger says: But Zeilinger uses it in his argumentation for his view. Look how he is doing it: Zeilinger discusses 5 ways out after the confirmation that QM violates the Bell inequalities. Deny realism Deny locality Deny counterfactual definiteness Accept superdeterminism Accept actions to the past He more or less discards 3 4, and 5 rather briskly. Of locality, as already cited early, he remarks that most physicists think that we should give up on locality. However he tends to give up on realism, because this seems to be the conclusion of the Kochen-Specker theorem, and its first empirical tests. So the KS theorem has directly nothing to do with Bell states. But for Zeilinger it is a hint that of 'local realism' (which, as Joigus explained means 'locality' and 'realism' taken together), we have to loosen our concept of a reality behind our quantum measurements. Please reread the chapter 'What could that mean?'. (Warning: he does not discuss these in the exact order as I did here. I streamlined his argument here. First he mentions the first three assumptions, then he argues against (3), then he discusses locality and realism, and only then he mentions superdeterminism, retro-temporal causation, just to discard them immediately.) @joigus: as you see, Zeilinger argues against superdeterminism. He treats it as a kind of 'last straw'. This is his argument: For completeness the 5th:

Hi Studiot! Does that mean the left and right side of the brain are entangled? Ok, back to business: I found a pdf of Zeilinger's book. This is the paragraph immediately after the paragraph @bangstromcited:

From a Dutch newspaper:

This is not fair. You should have included the next paragraph, where Zeilinger gives his own viewpoint. It fits pretty well to @joigus post. Pity enough I only have the the original German version, and translating from one foreign language to another one is a bit difficult. But in my summary: he carefully proposes that letting go realism is the better solution, and refers to the Kochen-Specker theorem, which leads to a similar solution, even without entanglement. Maybe you could cite this paragraph here too? Until now I could not find the text somewhere on the internet. So now, I can add Zeilinger to my list, but only half-half, because he does not express himself as strong as the others on the list. But his tendency is clear.

Yep, exactly what I wanted to show here: Sabine H says it very clearly: The correlations are greater than those allowed by a deterministic, local theory, not by quantum mechanics. So in QM the correlations are local. Sorry, the error is yours. Your interpretation is wrong. Compare with all citations @joigus made from the video, in which words like 'seems', 'appears', 'says' are heavily used. And in the sentences you cited, she sets the records straight. In QM there are no non-local causes/signals/information transfer/affects. I even just discovered that for my point 1 (of the three points above) has an official name: the no-communication theorem: My italics. So what is left? Correlation. And correlation can be faster than light even classically: that is the example of the left and right hand shoes. Condition is that the correlated 'events': opening the boxes; measuring spins, have a common history. And that they both have. Putting the two shoes in the boxes; creating two entangled particles. The only astonishing is that the correlation in QM is stronger than in classical mechanics. That definitely has a 'FTL odour'. But 'odour' is just as a physical concept as 'spooky', namely none. Coin flips can be explained classically. QM correlations cannot. And further I am still waiting of citations of authoritative QM experts that say that in QM there is 'spooky xxx' at a distance. So no simple text books, these are already critisised by Sidney Coleman. So reference to authorities, please. And of course no popular science books.

Hurray! Clauser, Aspect and Zeilinger got this year's Nobel prize!😃 Now the newspapers will be full of articles saying that they have proved non-locality with their experiments.🤪

It is even worse. @joigus, Sabine H has a blog, in which she spells out her videos, so you can read them in your own tempo. Here is the one of that video. And this is even 'worse' than what you quoted: And in the comments. A commenter: Next try! You keep repeating this. But my list becomes longer... Susskind Gell-Man Kracklauer Sidney Coleman (thanks, Joigus) Sabine Hossenfelder 2 Names added on the list thanks to your references... For clarity, let's take the following 3 propositions QM does not allow for FTL causation. Watch my wording: causation. So no signal, (inter)action, affect, or whatever. The conclusion of Bell's theorem is: no local hidden classical system can reproduce the correlations predicted by QM. These correlations were experimentally confirmed, so QM is right. Conclusion: the experiments can be explained by QM, without needing non-locality. Classically, we would need non-locality. So find an acknowledged author that rejects one of the 3 presumptions that together support that QM is local. If you keep repeating that the mainstream think QM is non-local, then it should be easy. But be careful not to shoot yourself in the foot again.

Water bear = tardigrade Essentially no different from experiment with a number of silicon atoms (the fullerene experiment.) I know what you said. My point was against how you argued for your position. Counting particles is not of importance, mass, or better momentum, of the bound system is of importance here. Good point. It were interference experiments, not entanglement experiments. But if bangstrom cannot just deliver tardigrades, but also a source of identical, entangled tardigrades, we could do the experiment. However, I am not sure to look for correlation or anti-correlation. Before I prepare the experiment, I have e.g. to know if tardigrades are bosons or fermions...

No, you turn it around: instead of providing references of QM specialists who see 'real superluminal connections', you provide a link to a physicist who denies none-locality, strengthening my position. Try again. Yes, you are completely right. I would suggest that you read Feynman's QED: The Strange Theory of Light and Matter. Then you can wonder why the principle of least action seems to work in classical physics (Lagrange formulation of classical physics, Fermat's theorem etc), in relativity, and in QM (QED). E.g. taking Fermat's theorem, how does the light in advance know what is the fastest way between two points? Must be non-locality... . OK, this was already reacted on by Joigus. However, @joigus, I think you make an error in your argumentation. Interference experiments with buckyballs have succeeded. But if I follow your argumentation regarding the tardigrades, and apply this to buckyballs, that would have been: 60 x 6 = 360 electrons 60 x 1 = 60 nuclei makes 420 particles Or should I go further, and count the nucleons? 60 x 6 = 360 electrons 60 x 12 = 720 nucleons makes a total of 1080 particles. I simply think, that because the nucleus is a bound state, it counts as one. The same for carbon atoms, the same for buckyballs. And I would then assume the same for basket balls, tardigrades in between, both being also huge bound states of matter. So I even think bangstrom's idea is correct, but the experimental confirmation may lie in a very far future. So I think you should just take the Broglie wavelength of the bound state as a whole. Sadly enough, Wikipedia does not mention the mass of tardigrades... Maybe in the far future we will have amusement parks, where they send you through two doors, so you can experience yourself what it is to go to through 2 doors at the same time. 😉. Why not, you can already experience free fall...

I am not aware of any QM physicist who would not agree with Susskind's position: Nothing that Bob does has any FTL influence on Alice's side. QM does not allow for such interactions. If you know of FTL interactions (i.e. FTL causal relationships allowed by QM), let me know. This would mean that the direction of cause to effect is agreed upon by all observers. Bell's theorem says that no classical theory can replicate all predictions of QM If you have any serious references, please post them. You're right of course that I cannot evaluate the correctness of Susskind's calculations. But for this kind of situation, there is only one option for me: wait, and see if this is (will be) a well established viewpoint of the physics community at the long term. As you call my approach 'philosophical', I would like to tell what my position is: in QM we have come at the limit of our, human, epistemological possibilities. We can measure particles arriving at a detector, measure some of their properties (but not all of them at the same time), or we can measure wave properties in the collective behaviour of many particles. These are physical, measurable results. But the wave function is not physical: we cannot measure it in itself. We cannot measure it (any experiment measuring the phase of the wave function? Or when it flips due to entanglement with a remote measurement?). It is part of a recipe to predict quantum events, but only in terms of probabilities. The wave function itself is not a physical object. Earlier I compared it with the use of the imaginary i. AFAIK QM cannot be done without it. It is not just shorthand to make some calculations easier, as it is in the description of classical wave mechanics. And this imaginary i stares you in the face in the Schrödinger equation! (Just to be honest, I read somewhere (I think it was in the blogs of Sabine Hossenfelder) that much of QM can be done without imaginary numbers, but not everything). At least I find it funny that a function is taken as a physical object. That its name is still a 'function' is at least suspicious. That is also the reason I cannot take MWI seriously. It heaves the existence of the wave function from a mathematical tool to physical reality. That is metaphysics. OK, give some of the same caliber as Gell-Mann and Susskind, that base their position on established mathematics of QM. Not of some metaphysical interpretation of it. (I found nothing of the kind in Susskind's book, just descriptions of experiments and mathematical derivations). I think you are confusing entanglement with plain superposition. I also know of experiments where they succeeded in doing double-split experiments with buckey-balls, and producing interference. Not with tardigrades. But if you have a source, let us know.

OK, I will cite a few lines from Leonard Susskind's Theoretical Minimum: Quantum mechanics. First he makes a mathematical derivation, that is of course is over my head, but the end conclusion is clear: With other words, QM does not need faster than light signals to explain entanglement, and QM obeys this speed limit. Recognise what Gell-Mann said in the video that Joigus linked. Then Susskind presents a setup with two computers, that each for themselves simulate quantum spin measurements, which is not impossible, if the random generator is good enough. However, he shows that in order to simulate entanglement, a faster then light connection is needed. (Italics in the original). So now you can do three things: show that Susskind made an error in his math stick your head in the sand or accept what one of great QM specialists is saying here. For me, I accept Susskind's, Gell-Manns (and Swansont's, and Joigus', and MigL's) position, even if I cannot follow the math. So I take the argument of authority. Such arguments are valid, when it is clear that Susskind and Gell-Mann are absolute 'quantum experts'. Just to give an idea of Gell-Mann: he predicted the existence of the Omega-minus particle, and is one of the fathers of the quark model of hadrons. I think for him this topic would be basic QM... Because QM is right: the 'superluminal correlation' is only needed when you want to understand entanglement classically.

Hi Joigus, No, I do not want to take the deep dive into the principles of the so-called 'quantum teleportation'. AFAIK, Zeilinger was the first experimentally proving that it is possible. I do not quite understand it, and I will not spend my mind energy on that now. I mentioned it, because I suppose that Bangstrom's idea of 'identity swapping' comes from these experiments, and not from entanglement experiments 'an sich'. It is an application of entanglement.

Yes, and you are human. And humans do not have the ability to visualise what is 'really going on'. That is why you have a problem here. As any other human. But QM is unambiguous: the measurements are local, but correlated. I think your postings are scattered with 'signal', 'cause', 'affect', 'action' etc. In QM superluminal signals are also impossible. The illusion of a superluminal signal only appears because one wants to understand what is happening from a classical viewpoint. Correct. So there is no signal, and it is superluminal? Reminds me of a bonmot of Pauli about Dirac's atheism: there is no God, and Dirac is his prophet. I assume this is in the context of 'quantum teleportation'. Quantum teleportation is based on entanglement, but it is a good trick, made possible on the basis of entanglement. Correlation. That is what we (if I may speak for Joigus, Swanson and MigL...) are calling it all the time.

Because in this experiment, there is no direction all observers can agree upon. Detection1 can be the first for one observer, while for another observer Detection2 is the first. So there is no superluminal signal from one detection to the other, because a signal always has a direction. Hiding behind the vague word 'nature' does not help you. Yep. Nature is not obliged to follow our capabilities to visualise how this happens; our visualisations are classical, per definition. The superluminal signal is only necessary if you want to reproduce entanglement with classical means. I scanned through Susskind's Theoretical Minimum about QM: he is making this argument very precise. Classically you would need direct action at a distance; QM does not. I would suggest to read this book. Stop using the word 'identities', this is very imprecise. I assume you mean properties. If not explain what you mean with 'identity' in this context. Zeilinger would not agree with you, because your use of the word 'affects', which is just another way of saying 'one measurement causes a change at the remote side'.

I was breeding on a similar, precise way to formulate what we really learn from Bell-like experiments. In the first place, we learn that the predictions of QM are correct. (I suppose that is the reason that Feynman threw Clauser out of his office.) Secondly, nearly the same formulation you used: No system, based on classical physics, can reproduce all predictions of QM. Only if you would introduce 'action at a distance', one could. But we know this is classically impossible, because of SR. @bangstrom: I think there is a rather clear experiment that shows that the correlation between the 2 distant measurements cannot be causal. And 'not being causal' implies: no communication is taking place between the two measurements, no superluminal signals none of the more or less equivalents of causality: effect, action, interaction, etc. applies. Now this is the experiment: in a Bell like experiment the distances of the detectors are exactly equal. So, assuming we use a photon/polarisation experiment, int the rest frame of the source of entangled photons, the photons will arrive at exactly the same time. Further, the detections are spacelike separated, so even light is not fast enough to reach the other detector (maybe superfluous, because using photons in the experiment it would be impossible anyway. We measure the correlations, which of course are exactly as QM says they will be. Now imagine 2 other observers: one is travelling in the direction of the first detector to the second, the other observer in exactly the opposite direction. For both observers, the detections do not occur at the same time. For Observer 1 Detection 1 will be the first, for Observer 2 Detection 2 will be first. However, SR demands 'conservation of direction of causality'. It cannot be that for Observer 1 Detection 1 causes Detection 2, and for Observer 2 Detection 2 causes Detection 1. Same holds of course for all other 'disguises of causality': communication, effect, interaction etc. This leaves us with the only other option, correlation. And as Detection 1 and 2 are outside their respective light cones, this correlation must have its origin somewhere else: the source of the entangled photons. 2 photons just leaving the entanglement source are of course in the light cones of Detection 1 and 2.* And this is what Swansont has already repeated a few times: the photons are correlated direct at the beginning. It is only when we look at it with a classical view, it seems we need 'action at a distance'. (That sounds like Joigus) A bit against Joigus and Swansont, I would 'cry out': "yes, but we, as macroscopic human beings, live in a classical world!" And therefore we are astonished about these results. But this is nothing new: QM is astonishing. But that is nothing new. Citations, just from my head: Bohr: Who is not astonished about QM, has not understood QM. Feynman: I do not understand QM. * An actual experiment, not exactly like the one I described, but I assume equivalent, was indeed done: From: Experimental test of nonlocal quantum correlation in relativistic configurations Bold by me, of course. Joigus, do you still not want to earn a beer?

A small correction to this: correlation always only shows up statistically. It is my understanding that this is already accounted for in Bell's unequality: QM measurements cannot be reproduced by introducing any local hidden variables. I think 'hidden' is the keyword here. Compared to the Clauser et al experiment, Aspect changed the polarisers after the photons left the source, and also did this so fast that it was impossible for the measurement devices to communicate, i.e. they were spacelike separated. BTW, I am still sitting on my problem...:

Then you have not understood my example. The source of the entangled photons lies in the middle between Geneva and Andromeda. No measurement is made there. The measurements are done in Geneva and Andromeda. No beer, sorry. To add to Joigus' reaction: the correlation is 100% if the polarisers are oriented in the same direction. So a single measurement would do the job (except no scientist would do it once, it could be accidental). However, the 100% correlation is not interesting, because it could just as well be explained by supposing the photons had their polarisation from the beginning. To show the stronger correlation, you must vary the orientation of the polarisers independently from each other. And that you can only do by doing many measurements, according Joigus' example. Only then the correlation turns out to be stronger than a classical theory, where the photons have a polarisation from the beginning.

Yes, what Joigus says here is also what I read everywhere. The landlady of the apartment on Helgoland thought Heisenberg had been in a fight or something, so bad he looked in his face. I've been on Helgoland: it is a small rocky island, very different from the main land around it, and I can't even remember that I saw one single tree. Pity enough I was there before I knew about Heisenberg having been there, and discovered his version of QM. And MigL, just for fun, Google 'Heisenberg Cocain', and you probably realise where the story comes from... It was good for a laugh at least. Oh, and a fat +1 for Joigus, of course.

To 1). I completely accept what rolls out of the math of QM. I 'read' Leonard Susskind's Quantum Mechanics: The Theoretical Minimum, but somewhere halfway I had to give up on the math, but at least I can more or less follow the argumentation. Maybe I should now reread the relevant chapters again, with the present discussion in the back of my mind. To 2): Ah, but I specified this immediate after that remark. Your quote from Gell-Mann: But that is exactly what I think. Some years ago I had a thought exchange about this with Swansont. If I remember correctly, I defended that the only thing one can say something about is what the result of a measurement of the entangled partner will be. (Of course this is only valid when e.g. polarisers are in exactly the same position.) However, I am completely convinced that nothing physically changes. I think the reason I retracted to this point, is that there indeed are many descriptions of Bell-like experiments where is said something like "If the polarisation of one photon is measured, the other one immediately flips in the same direction." As if some 'Quantum God' already sees how the wave function changed, before it is measured by a physical mortal. No, nothing flips, the only thing I can know for sure is what will be measured at the other end, if measured in the same polarisation direction. Swansont and Gell-Mann (Swansont, correct me if necessary),and you make it already to 'reality' because under certain circumstances you can with 100% certainty predict what the other end will measure if the measurement is made with the same polarisers in the same direction. But I have to confess, now I am getting confused myself. Thinking about this I could imagine superluminal communication, so there should be an error in my thinking here. It is easy to determine if a beam of light is polarised: just turn a polarisation filter in the direction that lets through the maximum of light intensity, and you know its polarisation directon. Now do the same with entangled photons located exactly between Geneva (for obvious reasons) and the Andromeda galaxy. In Geneva I measure a small stream of photons, with a polariser at 0o, and because the source of entangled photons is exactly in the middle, the entangled partner photons arrive there at the same time. The Andromedian measures in which direction they are polarised, and will also measure 0o. So it does not work with single photons, but with many it would work. I assume I am making some huge error here, but at the moment I do not see where. My mind-overflow alert is blinking red... The one with the clearest explanation where my error lies, gets a free beer (entangled with the one I will drink then, so take care it does not spill over...). I'll stop here for the moment, before my head explodes. Never realised 'honest thinking' can hurt so much. Ah, how easier life would be if one could simply stick to an ideology!

Now I got confused in my reading myself: Bangstrom is saying that the 'connection' (whatever that may be) is not causal. I must add that we have to torture nature to the limit, to empirically observe these correlations.

I understand that. For me however the mathematics of QM is a book with about 5 seals (if you know what I mean). What I am interested in is how physicists came to their hypotheses, and how these were empirically underpinned. (And of course the methodological and philosophical assumptions that go into these hypotheses). I always felt a bit disturbed by the lectures at university because physics was always presented as a ready made building. History of physics was one of my favourite subjects (and still is). And in my philosophy study, I was trained in reading (old) texts. I notice a few ambiguities in your position. First you said: I took this as 'final statement of Bell in this matter', but you reacted on it as if you read 'final statement in this matter' (in general). And now you are saying: Wouldn't be 'final' in his last years? Sorry for the ant fucking, but hey, I am a philosopher by education. (Not profession...) What is non-separability when a spacelike distance is involved other than non-locality? (Beware: correlation, not causation.) More or less. "Some element", yes. But we have no idea what this element is. Another problem I think I have is with: As for me the wave function is not a physical object, there is nothing physically updated. The wave function is an idea, and there is no problem for ideas to be superluminal (now I think about the war in the Ukraine, and now I am thinking about the Andromeda galaxy. Wow, 2 million lightyears in less than a second!) I know that the violations of Bell's inequalities roll out of the math of QM. You know the story that Feynman threw Clauser out of his office, because implicitly he was doubting QM? We know that QM predictions are empirically valid. But we don't know why. And my guess is we never will. I agree with that; however I am not so sure if it is Bangstrom's imprecise language (but he is not the only one guilty of that..). I however suppose that Bangstrom agrees that no information is transferred, and that the correlation between the remote measurements is not a causal relationship. @bangstrom: could you clarify, please, as precise as you can? I agree. But it is surprising that nature does something we can derive mathematically only, without knowing the ontological status of the wave function. I think I more or less agree with Bangstrom here: New word alert! Try to define these words, or try to say what you want to say without them. Nope. The correlation is not causal, as with the shoes in the boxes. The correlation however is stronger than we classically expect.

Hui, Joigus, now you have fallen into a trap. If it is your own, or the 'Journal de physique' (or some other source) I don't know, but Bell is citing Einstein in your highlighted passages: Here Bell is speaking for himself: And after his argument: It is obvious that Bell doesn't like this conclusion, and discusses 4 ways out: QM is wrong, at least in the case of such situations Superdeterminism (he doesn't name it like that, but is clear that he is pointing at that) Lorentz transformations are not valid There is no reality below some "classical" "macroscopic" level (quotation marks from the original) Concerning the first point: Aspect was still working on his experiments, and Bell refers to that. His comment: We know how the experiment went out... From other articles, I have reason to believe that he was going for the first point, i.e. that QM is incomplete. He was puzzled by the results of the Clauser and Aspect experiments. Bell says exactly the opposite of what you are saying. I think it is important that you all, discutants (my word creation?), are very clear with the words you are using. I give a few proposals: action (or interaction): a physical process, where energy and momentum are exchanged, and so special relativity applies correlation: as in the example of the shoes in the boxes To 1: even Bell is confusing here, because he says "They cannot be explained, that is to say, without action at a distance." (Bold by me) To 2: I would say that the Bell inequalities, together with the confirmation that they do not hold in QM in experiments, show that QM has stronger correlations than local realistic theories allow. For me, I go with Bell's 4th 'way out', at least for now. The wave function is part of a calculation recipe. Why it works, we simply don't know. Why it leads to non-local correlations, we don't know either. But the formalism of QM simply leads to the conclusion that non-local correlations are possible.

But I hope you remember what you said yourself: Bold by me. Is it not finally then? Of couse. I agree, insofar if you mean with a superluminal signal that it implies a physical causal process (which implicitly would mean transfer of energy and momentum), and that people therefore could use for FTL communication. I think one problem (maybe also part of my problem) is the status of the wave function. My opinion: the wave function itself is not a physical object, so e.g. in Bell like experiments with spin, when Alice measures the spin from here side, there is changing nothing on Bob's side. (See the example of the gloves). The wave function is not a physical object*, which simply means that nothing changes because of Alice's measurement. This would then even be stronger than what I just said: there is no superluminal signal. But there is definitely some form of none-locality. But I would say this just rolls out of the formalism of QM, in the end the results of experiments like Aspect's and is followups are often described as 'QM was right again'. * Therefore I cannot by in into the MWI. I understand that. QM is often called the best proven scientific theory we have. But we live in a classical world. And in this classical world it just looks like superluminal information transfer. A classical view must fail terribly. How should I imagine a wave function that is stretched over light years, and then collapses over its total length if we do a measurement at one of it's sides? Maybe that is the reason I like to declare the wave function as not-physical. It is part of a calculation recipe, not of nature. As a (dangerous?) analogy: the imaginary number i does also not represent any physical observation ('I walked 5i kilometers today'). But in our calculation recipes in e.g. QM, it plays an important role. So, and now to cheer up the discussion a little, some pictures: Bertlmann smells tea presented by John Bell. Mermin and Bertlmann (yes, a few years later...) Invitation for a talk by Bell in Vienna, with a student's addition.