Thanks for answering!
I guess I was confused by this:
What about the Ebborians? The Ebborians, you recall, have brains like flat sheets of conducting polymer, and when they reproduce, the brain-sheet splits down its thickness. In the beginning, there is definitely one brain; in the end, there is definitely two brains; in between, there is a continuous decrease of causal influence and synchronization. When does one Ebborian become two?
Those who insist on an objective population count in a decoherent universe, must confront exactly analogous people-splitting problems in classical physics!
Heck, you could simulate quantum physics the way we currently think it works, and ask exactly the same question! At the beginning there is one blob, at the end there are two blobs, in this universe we have constructed. So when does the consciousness split, if you think there's an objective answer to that?
That is a somewhat useful analogy, but it can be taken too far. But it seems to me to be saying the same thing (though perhaps not as clearly) as the inkblot above:
Can you really count it? Not really!
How many universes "branch off" from a "quantum event", and in how many of them is the cat dead vs alive, and what about non-50/50 scenarios, and please answer so that a physics dummy can maybe kind of understand?
(Is it just 1 with the live cat and 1 with the dead one?)