> But I have the luxury of not doing this for a living, and I'm very happy to be proved wrong by people who do. I'm in a similar (but likely even less knowledg

> But I have the luxury of not doing this for a living, and I'm very happy to be proved wrong by people who do. I'm in a similar (but likely even less knowledgable) position; I'm having trouble following your logic, presumably because it's relying on terms and results I'm unfamiliar with. > That means branch counting matters, which means there has to be some way for the universes to communicate the results of branch counting with each other. Otherwise there's no mechanism for probability to arise. I don't know what branch counting is, but I don't see how the various universes need to communicate with each other. Observers in most of the universes will agree with us about the probabilities, as that's what the history of those universes has shown. In a small but nonzero number of them, however, everything will have happened the way that classical physics predicts and they will have never come up with quantum mechanical theory in the first place. > Because otherwise you still have to explain how a split (or differential propagation or whatever you want to call it) in one location generates an entire universe instantaneously - i.e. faster than c - while preserving state that is beyond the event horizon of the current location. I don't see a problem conceptually with envisioning each split like a stress fracture that propagates at the speed of light. As information can't travel faster than that (per relativity), there's no need to envision the two new worlds separating from each other faster than that anyway.