Not really at the quantum level, at least not in the form that is typically understood as causality. There are all kinds of ways that you can interfere with probability and when you do, the “no taksie-backsies” rule goes out the window. You can prove this to yourself with a flashlight and 3 diffraction gratings.
That’s where probability manipulation really gets interesting.
My preferred conjecture is that all things exist, at all times, in all places, but only a fraction of all of those infinite-dimensional probability vectors will produce the act of your observation, so those are all of the vector-spaces that you can detect. We can’t observe, for example, a probability vector-space where water boils at 15c/1bar, or where e=3 because we would never have existed to observe within that environment. Perhaps other things exist and observe those places, but not carbon based biological life as we know it.
I think that the Casimir effect and especially Casimir pressure in constrained geometries, Zero point energy, the uncertainty principle and other observable phenomena point towards the possibility of a continuum of multiple overlapping observable probability fields, but obviously that could be just a convenient hand wavy explanation.
In the bandwidth of overlapping probability fields flavour of MWI there is no branching or creation of new realities, merely extant vector spaces drifting in and out of observability based on probabilistic functions. Vector spaces within observability tend to be similar, and the overall aggregate sum is what we perceive as a unified observation.
As we make changes that manipulate this probability space, new probabilities dominate our perception. The apple was very unlikely to be seen on the table until we moved it there, making it then extremely probable to be observed in that position.
There are some very interesting ramifications that appear to be observable phenomena if this line of thought is drawn out to its extrema. It’s one of my favourite possible models.
Perhaps one day I or someone else will figure out how to experimentally test the idea, but so far it seems to be unfalsifiable (which obviously doesn’t mean that it is more correct, just that it’s hard to test, like the simulation conjecture and many others)
I should have also made it clear that the probability vector-spaces that become unobservable include those where you got hit by a bus, and all of the coherent/adjacent spaces to that event. So the bandwidth of perceivable “universes” keeps shrinking to lesser infinities as you go through life.
In addition, the perceivable vector spaces where you can talk to your friend also includes only those where she also got missed by the bus, and to a lesser extent all those who are connected and perceivable through communications… the act of communication being a constraint to the infinities of perceivable vectors where the communication would be possible, making us much more constrained as a society than we would have been when distant people had little or no contact.
There are a lot of interesting implications of this conjecture that may go some distance in explaining subjective human experience.
Um, sorry, how does that experiment prove anything quantum? It's explained entirely by Malus' law of I = I0 * cos^2(alpha) which has an entirely classical, simple wave-theoretical explanation (even if Malus himself was an emissionist and derived his law by introducing transversal asymmetry in the light corpuscles).
Malus’s law does indeed describe the amplitudes of the resulting light, but it does not say “why”, only how. In the same way that Newtonian physics assumes gravity but fails to explain its existence.
For more in depth look at this there is a 1995 paper by K Wódkiewicz contrasting the corpuscular formula with the quantum explanation IIRC.
Obviously, despite its explanatory power, we know that QM is incomplete so YMMV, but I’ll take QM over light corpuscles, until something better comes along.
Having light corpuscles that have poles and can experience fits of easy transmission/reflection is not much mathematically different from having photons with spins and wave phases, to be fair.
And Malus' original justification of his law straightforwardly carries over to the photons.
