in some of the worlds you are spirited away at near light-speed by evil aliens, and the measure of those worlds becomes relatively large once your “stationary” (in some sense) copies die out.
What matters, presumably, is the relative measure of worlds within the “branch” that you’re “already in”. Or, in other words, once you’re in branch a_1 (rather than b_1) at time t_1, the probability that you end up in branch a_{12} at time t2 is the conditional probability P(a_{12}|a_1) rather than the prior P(a_{12}) at time t_0. So it’s very unlikely to jump into a b-branch future from an a-branch past.
There is a subset of worlds in the branch “a” (or any other branch) where the aliens carry away your body at high speed. And this branch will eventually dominate any other subbranches (where you are still alive) of the same branch.
“Eventually” doesn’t do it. They have to dominate right then, at the moment of branching.
Let’s say that at 9:00 am you split into two branches, one where you stay on Earth, and one where you’re kidnapped by aliens traveling at high speed. At 9:05 am in the Earth branch, you fall off a cliff, and so most Earthly copies of you die, except for a few who get saved by some weird miracle. Suppose that at 9:30 am one of miraculously-saved copies attempts suicide. Again, that kills off most of the remaining Earth branches, but the few that remain have now experienced two miracles. Et cetera.
You seem to be saying that, eventually, after a sufficiently large number of miracles, the remaining branches have even smaller measure than the”alien” branch that diverged at 9:00 am, so therefore suicidal Earth copies at 10:00 am are likely to experience a sudden relativity-violating teleportation to an alien ship. And I’m saying no, that doesn’t follow, because of the survivor branches diverging at 10:00 am, most involve being saved by some relativity-obeying Earthly miracle, not teleportation to an alien ship. The overall greater measure of the 9:00 am alien branches is irrelevant to the 10:00 am Earth copies; what matters to the 10:00 am Earth copies is the relative measure of the branches splitting off on Earth at 10:00 am. Branches that split off before that don’t count.
Maybe I misunderstand the setup. I thought that in this model the state of one’s life at 10am is determined by averaging over all the remaining copies in all branches, including those on the alien ship from 9am. As you keep trying to suicide, you fade out of your existence on Earth and into the ship. Did I get the setup it wrong?
As you keep trying to suicide, you fade out of your existence on Earth and into the ship. Did I get the setup it wrong?
Very much so, as far as I understand. Indeed, if it worked the way you suggest, presumably we’d be fading in and out of places all the time as the wavefunction evolves, rather than having a single coherent conscious experience.
I can’t math, but as I understand it, branches merge only when they happen to become identical. So, unless your earthbound suicide attempts end up putting you in a situation physically indistiguishable from your MWI-cousin on an alien ship, you won’t merge.
What matters, presumably, is the relative measure of worlds within the “branch” that you’re “already in”. Or, in other words, once you’re in branch a_1 (rather than b_1) at time t_1, the probability that you end up in branch a_{12} at time t2 is the conditional probability P(a_{12}|a_1) rather than the prior P(a_{12}) at time t_0. So it’s very unlikely to jump into a b-branch future from an a-branch past.
There is a subset of worlds in the branch “a” (or any other branch) where the aliens carry away your body at high speed. And this branch will eventually dominate any other subbranches (where you are still alive) of the same branch.
“Eventually” doesn’t do it. They have to dominate right then, at the moment of branching.
Let’s say that at 9:00 am you split into two branches, one where you stay on Earth, and one where you’re kidnapped by aliens traveling at high speed. At 9:05 am in the Earth branch, you fall off a cliff, and so most Earthly copies of you die, except for a few who get saved by some weird miracle. Suppose that at 9:30 am one of miraculously-saved copies attempts suicide. Again, that kills off most of the remaining Earth branches, but the few that remain have now experienced two miracles. Et cetera.
You seem to be saying that, eventually, after a sufficiently large number of miracles, the remaining branches have even smaller measure than the”alien” branch that diverged at 9:00 am, so therefore suicidal Earth copies at 10:00 am are likely to experience a sudden relativity-violating teleportation to an alien ship. And I’m saying no, that doesn’t follow, because of the survivor branches diverging at 10:00 am, most involve being saved by some relativity-obeying Earthly miracle, not teleportation to an alien ship. The overall greater measure of the 9:00 am alien branches is irrelevant to the 10:00 am Earth copies; what matters to the 10:00 am Earth copies is the relative measure of the branches splitting off on Earth at 10:00 am. Branches that split off before that don’t count.
Maybe I misunderstand the setup. I thought that in this model the state of one’s life at 10am is determined by averaging over all the remaining copies in all branches, including those on the alien ship from 9am. As you keep trying to suicide, you fade out of your existence on Earth and into the ship. Did I get the setup it wrong?
Very much so, as far as I understand. Indeed, if it worked the way you suggest, presumably we’d be fading in and out of places all the time as the wavefunction evolves, rather than having a single coherent conscious experience.
And how would we tell?
I’d appreciate if you point me to the setup you are working with.
I can’t math, but as I understand it, branches merge only when they happen to become identical. So, unless your earthbound suicide attempts end up putting you in a situation physically indistiguishable from your MWI-cousin on an alien ship, you won’t merge.