The problem here seems to be a deliberate conflation of "logically equivalent claims" (which are two sets of claims entailing precisely the same set of statements entirely independently of whether those statements are a good or even testable model for a physical pheonomenon) and "physically equivalent states" (which are two ostensibly different states which are the same at every level of examination), or a deliberate conflation of the model of a phenomenon with the phenomenon itself. This conflation is, in either case, completely solipsistic, and arguing with solipsists is futile.
I'll leave the two of you to congratulate yourselves on being both brains in vats and not brains in vats at the same time.
I don't see how decoherence is an automatic win for MWI. Decoherence has been used in several different interpretations of quantum mechanics, notably in consistent histories and in certain hidden variable interpretations. Why should we choose MWI before those, particularly since it seems less parsimonious than consistent histories? For that matter, the language of Rovelli and Smolin's relational quantum mechanics very nearly turns decoherence into its own interpretation (if you compare papers on decoherence which shirk the metaphysical interpretation to...
Throw something over that edge, and it ceases to be.Sweet Jesus! Observers in asymptotically flat spacetime don't ever see something go over an event horizon. They just see it get pancaked onto the thing. Interestingly, in proper time, you're still probably wrong.
So there isn't even a theoretical distinction between them.You were making perfect sense right up to this sentence (I suspect that's because you were just rephrasing something I've already said). That sentence, though, has sadly brought us back to where we started: your perpetual conflation of metaphysics with epistemology. Scientific theories and ontologies aren't the same thing. If you think the latter is baseless, that's probably right, but I'd think that would give you added incentive in making sure that you understand the difference between a model and the reification of that model.
By the way, you still have a contradiction to explain away.
You aren't paying attention. Theories make predictions, interpretations of theories do not. In any case, suppose we grant you your little maxim. Then, if we can't tell the difference between an interpretation which claims that wavefunctions and their collapses are real and one which explicitly claims that they are not real by experiment, they're equivalent. Your maxim has just given us that wavefunctions are metaphysically real if and only if they are not.
And, in any case, someone who reacts against metaphysical realism should also take the brain in th...
There is no difference at the level of predictions, because I'm not calling for any new laws of physics beyond QM. It's a matter of what makes sense as interpretation.The reason for that lack of difference is that every interpretation of a physical theory is an attempt at reifying the theory in some sense. Each interpretation must conform to the theory at every level of examination since the interpretation is an ascription of a certain ontology to that theory, not a modification of that theory. But it isn't the ontology which predicts things, it's the m...