alt Hacker NewsDecoherence gets you a diagonal density matrix description of the world. It doesn't get you a single-state description of the world. Going from "There are many parallel universes" to "and we are in one of them" still takes a lot of handwaving.
Decoherence gets you a diagonal density matrix description of the world. It doesn't get you a single-state description of the world. Going from "There are many parallel universes" to "and we are in one of them" still takes a lot of handwaving.
But we're not in one of them. We're in all of them. Yours is a misunderstanding of how it feels to be in a quantum superposition. There's no component of the wave function in which Schrodinger's cat experiences anything other than being alive or being dead. There's no component in which it feels like it's in some ghostly combination of both outcomes. Both components of the wave function exist in superposition, and to the extent that they are decoherent, they do not interact and do not even notice that they have company. I don't mean this only as an academic statement; it's also true of you and me, at this very moment.