Circular. You have to already accept many worlds to take this as evidence of worlds. You can argue for Many-Worlds on grounds of parsimony and clarity, but that's it.
No I don't think so. Many worlds is basically the hypothesis that we can put arbitrarily large systems in superposition. Like schroedingers cat that is both dead and alive, but instead it could be the whole lab, the whole planet, the whole galaxy that is simultaneously in two different states.
We could test this by trying to actually do it, by putting really large and complex systems in superposition. If they both evolve as we'd predict and cause the interference patterns we predict, then we must conclude that these "other-labs", "other-planets", "other-galaxies", "other-worlds" evolve just like ours, and have a causal effect on ours.
Saying that sure, they evolve like ours, and sure they affect ours, but even so they are not real - that is I suppose one stance, but then you are getting pretty close to solipsism.
I thought there's a quasi-classical approximation of quantum gravity, it doesn't work only for event horizon due to infinities there, but should work fine for diffuse matter, like how most calculations for electron orbitals use classical electromagnetic field.
> Saying that sure, they evolve like ours, and sure they effect ours, but even so they are not real - that is I suppose one stance, but then you are getting pretty close to solipsism.
No, you'd get something like Bohmian mechanics, or Rovelli's relational interpretation. Which is my point: you can only take this as evidence of other worlds if you basically smuggle those assumptions in.
Just go full Idealism. All things that can be - just are. A block universe, of all possible things and all possible interrelation of things. A giant timeless crystal of qualia. It's pretty obvious to me now.
One location in the latent space of a latent diffusion model is a view into a universe that is as real as ours. That half cat, half dog monstrosity you accidentally created. It exists as a drawing, or as a physical mass of flesh, with every possible back story as to how it got there. And also every possible future.
And what are the electrons? AFAIK, they are excitations within a quantum field. And what's a quantum field? Each layer down seems to get closer and closer to pure mathematics.
Me too but... It would still be some form of mathematics as soon as you tried to write it down in a neat, precise way for others to understand it. Maybe exotic math, but still math :p
But what are the worlds?
My feeling is that Max Tegmark has it right. Everything is mathematics.