Challenging local realism with human choices

Max

I'm still struggling to understand your point, to be honest. You seem to be implying I'm misunderstanding something, but you don't seem to want to be explicit. Or maybe you're just saying that I shouldn't find the effects of entanglement strange, because you don't. If so, I don't think it's very helpful unless you can communicate why it doesn't seem strange to you, beyond saying "That's just quantum mechanics."

I think that's a bit rich to say I'm not being helpful...

You've already said entanglement is not "...the result of a cause that's common to the two measurements".

Where as I have repetitively pointed out in this thread that this correlation comes about as a consequence of the preparation of the initial system state (i.e. both particles past association). But you just ignore my comments, and go on to exclaiming puzzlement in trying to understand entanglement using classical correlations.

Where as I'm trying to point out the futility of trying to explain observations of entanglement using a classical mechanism. And that it's meaningless to ask questions similar to "but how does it work?".

Max

The phrase you quoted from my earlier comment didn't (of course) relate to "entanglement". Here it is in its proper context:
The aspect of synchronicity that this [correlation between measurements on entangled particles] seems to resemble is the "temporally coincident occurrences of acausal events" in the description you quote, because the observed correlation is "acausal" in the sense that it's neither the result of one measurement causing the other, nor the result of a cause that's common to the two measurements.

Earlier I'd specified that there couldn't be a causal relationship between the two measurements "on the assumption that a causal influence can't travel faster than light".

As for the substantive question, it's evidently still a controversial question among physicists whether causal influence (as opposed to communication) can travel faster than light. You may be interested to have a look at this comment by Howard Wiseman, published in Nature in 2014:
https://www.nature.com/news/physics-bell...es-1.15435

Wiseman characterises the choice left to us by Bell's work as follows:
either causal influences are not limited to the speed of light, or events can be correlated for no reason.

Wiseman's claims aroused controversy, but his opponents were those who believed that in the light of Bell's work there can be no general speed-of-light limit on causal influences. See, for example, this response by Norsen to Wiseman's paper on Bell's Theorems, published in 2015:
https://arxiv.org/pdf/1503.05017.pdf

As for the substantive question, it's evidently still a controversial question among physicists whether causal influence (as opposed to communication) can travel faster than light. You may be interested to have a look at this comment by Howard Wiseman, published in Nature in 2014:
https://www.nature.com/news/physics-bell...es-1.15435

Wiseman characterises the choice left to us by Bell's work as follows:
either causal influences are not limited to the speed of light, or events can be correlated for no reason.

Wiseman's claims aroused controversy, but his opponents were those who believed that in the light of Bell's work there can be no general speed-of-light limit on causal influences. See, for example, this response by Norsen to Wiseman's paper on Bell's Theorems, published in 2015:
https://arxiv.org/pdf/1503.05017.pdf

As I said earlier, I can't really help you, You'll have to get there by yourself. As regards the articles you've mentioned, you can find all sorts of papers on Quantum physics if you go looking for support of a position. But the main postulates seem solid, and have been known about for years.

I've found my own QM journey a bit analogous to letting go of childhood ideas of direct perception, and moving towards indirect ideas of perception. Only to realize after I made the move, that things are more subtle, and finding I can move back a little, to new position which probably accepts different parts of both general ideas of perception, and something more too. But the journey I've made had to be taken in these steps.

I dare say I'm all the better for it.

As I said earlier, I can't really help you, You'll have to get there by yourself. As regards the articles you've mentioned, you can find all sorts of papers on Quantum physics if you go looking for support of a position. But the main postulates seem solid, and have been known about for years. 

I really don't know why you think I want you to help me. I've just been trying to get you to explain the comments you've been making here. I'm afraid I'm far from convinced that you've grasped what's going on.

I really don't know why you think I want you to help me. I've just been trying to get you to explain the comments you've been making here. I'm afraid I'm far from convinced that you've grasped what's going on.

That's fine, as I explained earlier, it is a hopeless task for me. I have explained that the correlation comes about as a consequence of the preparation of the initial system state, both Bell particles association in the past, but that's not good enough for you, you still want to know how to explain it from the position of classical correlations. But no such explanation is possible. It's not going to happen. I've pointed you towards Roland Omnes work, and Consistent Histories.

Quantum mechanics is a more fundamental description of nature, it's new, and different, and you have to think differently about nature. It's not possible to understand this more fundamental description of nature using less fundamental classical mechanisms.

That's fine, as I explained earlier, it is a hopeless task for me.  I have explained that the correlation comes about as a consequence of the preparation of the initial system state, both Bell particles association in the past, but that's not good enough for you, you still want to know how to explain it from the position of classical correlations.

If you think that, you've misunderstood badly. And I have to say the accusation is ironic coming from you, given the assertions you've made in this thread.

If you think that, you've misunderstood badly.

Nope, I don't think I have.

Max

Why does it not surprise me that you think you know what's in my head better than I do myself? 

But seriously, it does present a problem for discussion when someone continually just says "No, you are wrong," and won't produce any evidence to back up the assertion, or even explain why they think so. 

I won't try any further to discuss this with you, but what I don't want is for anyone else still reading to get the impression that your assertions in any way reflect a consensus understanding among physicists. They don't, partly because there is demonstrably no such consensus understanding. Here are links to a couple more recent papers reflecting the continuing controversy, by Stephen Boughn and Federico Laudisa:
https://arxiv.org/pdf/1703.11003.pdf
https://arxiv.org/ftp/arxiv/papers/1705/1705.01356.pdf

Boughn's position is the closest I've seen in the recent literature to yours, Max, and I'll try to have a closer look at it when I have a chance. If you can bring yourself to read the introduction you'll understand what I mean about the lack of a consensus on these issues. I noted particularly the quoted view of a "distinguished Princeton physicist" that:
"Anybody who’s not bothered by Bell’s theorem has to have rocks in his head."

There's a story among mathematicians about a lecturer who remarked in passing that something was obvious, and was asked by a student to explain. He left the lecture theatre and didn't reappear for half an hour. He then said "It is obvious" and continued the lecture without further comment. The paper in which Boughn explains his position is 23 pages long.

...

Earlier, I pointed you at very knowledgeable people who I think get it... Like Omnes, Motl, Feynman, Zeilinger... they are certainly worthwhile reading...

Maybe it's worth noting one other proposal here. The paper by Leifer and Pusey was published in Proceedings of the Royal Society A nearly a year ago, but for some reason an article about it just appeared and was picked up by Daily Grail. There's a clearer discussion at phys.org here:
https://phys.org/news/2017-07-physicists...uture.html
And an earlier draft of the paper is here:
https://arxiv.org/pdf/1607.07871.pdf

This provides an alternative way around Bell's Theorem, which would allow both locality and realism, namely for information to pass between the entangled particles by retrocausality. The authors take an earlier result showing that under a realist assumption, time-symmetry implies retrocausality, and generalise it by replacing the realist assumption with a different one which they call lambda-mediation. If I understand correctly, the idea is that there would be nothing in the laws of physics to forbid signalling from the future to the past, but only something in the state of the universe - analogous to the view that the thermodynamic "arrow of time" is a result of boundary conditions rather than time-asymmetric physical laws.

Of course, there's a strong underlying assumption here that signalling from the future to the past must be prevented somehow, because it is never observed. In other words, the experimental evidence for precognition is assumed to be bogus.