What is problematic about the many-worlds interpretation. Even without non-locality, it solves the non-determinism problem, which seems far more problematic to me.
EDIT: well that's not a great explanation of why I dislike the many-worlds hypothesis, let me try again. Like some other ideas, including the existence of God, it's not (yet?) falsifiable. Which doesn't make it false, of course. But it's a really extraordinary idea. It's not just many worlds, it's a fuck-ton. And what can we do with all of them? Are they for nothing? Does nothing that happens matter because it happened differently in a separate but equally real "world"?
I guess, I can believe that "god plays dice with the universe", but I can not believe that "god makes infinite copies of the whole universe and tries all possible quantum outcomes".
EDIT: response to parent edit
Almost by definition interpretations are not falsifiable. The many world interpenetration is literally equivalent to the other interpretations, because they all describe how we understand the meaning of the same mathematical model; and it is that model that is making predictions.
In my opinion (as a mathematician, not a physicist), the many worlds interpretation is the more natural way to read quantum theory. That is to say, if I were tasked to design a universe given quantum physics as the specification, my naive implementation would correspond to the many worlds interpretation.
An equally valid interpretation is that we are a computer simulation, and quantum physics describes the rounding behavior of said simulation. As far as I am concerned the only point of having an interpretation is to help build an intuition for the models.
Another way of looking at it is that there's only one "world": the amplitude distribution over quantum configuration space. https://www.quora.com/How-does-observation-collapse-probabil... has a decent explanation/argument.
Or zero. (But it's definitely not one.) Personally I find the zero-worlds view to be the most intuitively satisfying:
http://www.flownet.com/ron/QM.pdf (Or the movie version: https://www.youtube.com/watch?v=dEaecUuEqfc)
David Mermin's Ithaca interpretation is essentially the same thing:
http://arxiv.org/abs/quant-ph/9609013
The slogan is that "we are correlations without correlata".
If the latter, then I would ask, "Do you believe the ocean is deep, even though you can only see the surface?"
I don't really understand the ocean metaphor, since humans have seen below the surface, quite a distance with remote-controlled submersibles.
Because of the expansion of the universe, it is theoretically possible for me to get in a space ship and travel away from you at such a high speed that we would never be able to meet again, even if at some point we both decided to head back toward each other as fast as possible, and even if we were both immortal. Our light cones would no longer intersect.
Probably you would assume that I continue to exist, despite that for all intents and purposes I cannot affect your life in anyway and therefore "don't" exist.
Similarly if I crossed the event horizon of a black hole.
I believe that a qubit is in superposition (i.e. exists in multiple miniature "universes"), because that theory produces results that are consistent with experiment. When the qubit's universes de-cohere with mine, such that for all intents and purposes I can now only ever observe the qubit in one particular state, why should I assume that the other universes have ceased to exist? Decoherence is a continuous process, just like traveling outside of a light cone, so why treat them any differently. It's rather arbitrary to say that increased distance in space preserves existence, while increased distance in phase space does not.
MWI says that probability is conserved across the multiverse (unitarity of the global wavefunction)! The only reason we can "create universes" is because we're in the low-entropy time near the Big Bang. As we start getting closer to the heat death of the multiverse, then less "universes" are being created, because there's no room for them. In fact, given enough time, eventually some of the "universes" will actually join back together! If the multiverse is finite and closed (we don't know this), then sooner or later (like e^2^120 years later, according to a back-of-envelope calculation I saw) all of the universes will be lucky enough to join back up (Poincare recurrence), and we'll end up where we started.
I like looking at MWI not as the creation of universes, but as the creation of perspectives on one universe. In any case, it obeys conservation laws.
Briefly, there's no way to explain the statistical correlations between spin polarization states: if we measure the polarization of a photon in a basis that's only, say, 5 degrees offset from its known polarization, the statistical breakdown between the two resulting polarization states is something like 9:1; what if it's only a few arc-seconds off? Then the universe must divide more and more finely.
You quickly realize the universe must be infinitely-divisible (because quantum collapse occurs so often, and each collapse anywhere in the universe must divide the universe, it can't even be discretized at, say, some Planck-like scale).
That said, it does neatly solve local realism. But you have to believe in an immortal soul or something non-material -- I believe that has to be the 'weighting factor'. (Again, that was the uncomfortable conclusion of my paper, wish I could conjure more of it.)
I use it to mean that there are no outside forces describing the state of the universe beyond what's materially measurable/describable; in other words, probably we have no transmaterial soul.
That's a strong assumption for anyone who's religious, but it's sort of gospel for atheists. That said, it's the many-worlds hypothesis doesn't square with a totally-naive interpretation of Bell's Inequality and materialism/atheism.
So... are you saying that we have to admit there's a God/transmaterial soul / some other magical thing because we don't understand the implication of Bell's inequality? If so, that's a big jump, but I can't say it's wrong. Just that I don't take that leap along with you.
You know, there are more things in heaven and earth, Horatio, than etc etc. For both of us.
I'm probably not using the same definition. I'm just of the view that what we think of as material often gets reduced to atoms or particles representing the four forces for which no other 'outside' component can be entertained to exist. To me, this is a over simplification that erases all the other seemingly non-material components of our material world (thoughts, feelings, experiences, math itself, and etc). It's easy to assume it to be true, but every time I bump into this argument I always point out that the number 1 isn't of any singular substance but the number itself exists everywhere there is any form of divisibility or unitary attribute in use.