Classical physics isn't exactly computable, because some systems are critically dependent on their initial conditions, and an exact specification of the initial conditions requires an infinite amount of information (unlimited precision real number).
What happens if the branch “you” are in gets cancelled with another branch?What happens if the branch “you” are in gets cancelled with another branch?
That can only happen if the "branches" or "worlds" are still in a coherent superposition.
There is an approach to MWI based on coherent superpositions, and a version based on decoherence. These are (for all practical purposes) incompatible opposites, but are treated as interchangeable in Yudkowsky's writings.
The original, Everettian, or coherence based approach , is minimal, but fails to predict classical observations. The later decoherence based approach, is more emprically adequate, but seems to require additional structure, placing it's simplicity in doubt
Coherent superpositions probably exist, but their components aren't worlds in any intuitive sense. Decoherent branches would be worlds in the intuitive sense, and while there is evidence of decoherence, there is no evidence of decoherent branching, as opposed to decoherence.
Copenhagen interpretation isn't a theory-as-opposed-to-an-interpretation...and doesn't claim.to be. Although you could complain it isn't saying much as an interpretation either.
Bohmian mechanics has the opposite problem: it's definitely a theory , because it has additional mathematical structure, and it definitely has an ontology. But for all the additional complexity, it struggles to predict the full set of results. It doesnt reproduce everything that standard QM can do, and it isn't simpler, so there is no pragmatic case for using it. But there is such a pragmatic case for using CI, interpreted correctly as the minimum set of assumptions necessary to get the results, not incorrectly as a synonym for objective collapse.
On the other hand there is no other alternative. There is no other choice that preserves probability over time.
Which probability? MWI preserves objective probability, but but MWIers still.need to disregard unobserved measurements in order to get the right subjective probabilities.
This is a crucial point. The world does not come with "matter" and "laws" separately
In your vocabulary, it comes with matter and compressibility.
If you are talking about mainstream, professional philosophy, then , no, because it's very basic in that context. If you are talking about the average person then, yes, it's a very useful first step.
(Mainstream philosophers may not use the exact words, but that is of little significance).
The map/territory distinction allows you to state a range of positions, and maybe make a few claims like "just because it's in the map, it doesn't mean it's in the territory. It's not a solution to everything.
It is possible to derice Bor's rule from very general conditions that would apply to almoist any version of QM, Eg.
https://arxiv.org/pdf/2006.14175.pdf
(NB, that's Born's rule, not measurement, collapse, decoherence, etc).