Science
In reply to the discussion: Quantum Entanglement, Dark Counts, Coincidence Detection [View all]mindwalker_i
(4,407 posts)until we looked closer and it didn't. I would say that in our everyday perception, we don't see causality being violated, which is probably a good thing. However, we've seen that what we're used to seeing is definitely not the whole picture several times, like with relativity and QM.
At the end of 2011, Scientific American had a special issue on time. One of the main points was that we don't know what time is: Einstein said it was a very persistent illusion, and time tends to cancel itself out of equations. There's nothing that indicates why time exists except for our persistent perception of it passing.
Causality is deeply linked with time, so if we don't know what time is, it's at least reasonable to be suspicious of causality.
Another thought I've had on occasion is that special relativity talks about objects gaining mass as they move faster (relative to an observer - both the "fast" part and the "gaining mass" part). Because of this, getting over the speed of light would take more than infinite energy, but the case of quantum entanglement is very different. When two photons are entangled and go in separate directions, the little fuckers aren't passing a basketball back and forth or anything like that. They aren't exchanging virtual particles between each other, it's just a nonlocal aspect of the universe that they're part of the same thing.
Thus, it makes sense exchange of information between them would not be subject to special relativity - there's to stuff to gain mass. And it's already been demonstrated that the effects of collapsing into known states ignores relativity and time - I'm talking about the two sets of entangled photons with entanglement swapping. It seems to me that by measuring how often the two measured photons had the same polarization, one could very quickly determine whether the entanglement-swapping measure was going to take place in the future. Hence that already demonstrates retrocausality.
Of course, it want it to be that way because it would be cool