“Many-Worlds doesn’t say ‘everything possible happens’; it says ‘the wave function evolves according to the Schrödinger equation.’ Some things don’t happen, because the Schrödinger equation never leads to them happening. For example, we will never see an electron spontaneously convert into a proton. That would change the amount of electric charge, and charge is strictly conserved. So branching will never create, for example, universes with more or less charge than we started with. Just because many things happen in Everettian quantum mechanics doesn’t mean that everything does.”