Yes, since you don’t expect the copy of you on planet A to go anywhere, it would be paradoxical to decrease your probability that you’re on planet A.
Which is why you have a 100% chance of being on planet A. At least in the third-person, we-live-in-a-causal-universe, things-go-places sense. Sure, in the subjective, internal sense, the copy of you that’s on planet A can have a probability distribution over what’s outside their door. But in the sense physics cares about you have a 100% probability of being on planet A both before and after the split, so nothing went anywhere.
Subjectively, you always expected your estimate of what’s outside the door to change at the time of the split. It doesn’t require causal interaction at the time of the split because you’re just using information about timing. A lot like how if I know the bus schedule, my probability of the bus being near my house “acausally” changes over time—except weirder because an extra copy of you is added to the universe.
Yes, since you don’t expect the copy of you on planet A to go anywhere, it would be paradoxical to decrease your probability that you’re on planet A.
Which is why you have a 100% chance of being on planet A. At least in the third-person, we-live-in-a-causal-universe, things-go-places sense. Sure, in the subjective, internal sense, the copy of you that’s on planet A can have a probability distribution over what’s outside their door. But in the sense physics cares about you have a 100% probability of being on planet A both before and after the split, so nothing went anywhere.
Subjectively, you always expected your estimate of what’s outside the door to change at the time of the split. It doesn’t require causal interaction at the time of the split because you’re just using information about timing. A lot like how if I know the bus schedule, my probability of the bus being near my house “acausally” changes over time—except weirder because an extra copy of you is added to the universe.