Can retrocausality solve the puzzle of action at a distance?

Taming the quantum spooks: Reconciling Einstein with quantum mechanics may require abandoning the notion that cause always precedes effect

Huw Price

Some readers may raise a more global objection to retrocausality. Ordinarily, we think that the past is fixed while the future is open, or partly so. Doesn’t our freedom to affect the future depend on this openness? How could we affect what was already fixed? These are deep philosophical waters, but we don’t have to paddle out very far to see that we have some options. We can say that, according to the retrocausal proposal, quantum theory shows that the division between what is fixed and what is open doesn’t line up neatly with the distinction between past and future. Some of the past turns out to be open, too, in whatever sense the future is open.

To understand what sense that is, we’d need to swim out a lot further. Is the openness ‘out there in the world’, or is it a matter of our own viewpoint as agents, making up our minds how to act? Fortunately, we don’t really need an answer: whatever works for the future will work for the past, too. Either way, the result will be that our naive picture of time needs to be revised in the light of a new understanding of physics – a surprising conclusion, perhaps, but hardly a revolutionary one, more than a century after special relativity wrought its own changes on our understanding of space and time.

Still, we we want to explain why the kind of retrocausality involved in the Parisian zigzag needn’t allow us to send signals to the past. We are going to do this by examining an experiment in which standard quantum mechanics predicts the mirror-image: the same subtle causality directed to the future, achieved without signalling to the future.

Thanks. I found that interesting.

One pertinent point is the reason why Bell dismissed the retrocausal explanation for "spooky action at a distance":
"There’s a clue in a letter that Bell wrote to one of us in 1988. Huw Price was a young philosopher in Sydney at the time, and plucked up the courage to send Bell two of his early papers about this retrocausal idea. Bell kindly wrote back, saying: ‘When I try to think of [backward causation] I lapse quickly into fatalism’ and referred to a published discussion for ‘what little I can say’ about the matter. However, the published discussion is about an entirely different way of rejecting Bell’s statistical independence assumption, an idea that Bell called superdeterminism. In fact, he had good reasons to reject superdeterminism. But he didn’t see the difference between the two proposals, apparently, and threw out the retrocausal baby with the superdeterminist bathwater."

It would still fall short of explaining Wigner’s Friend.