That there is an external world. Which, in this case, happens to be a multiverse.
You seem to be taking an epistemology-flavoured approach, where realism depends on having a set of facts, rather than a set of things. But even at that, it’s not clear that multiverses imply a lack of facts. If there is a duplicate me somewhere that didn’t just type that sentence, that doesn’t indicate an lack of clarity about what I did , any more than if I had a twin who didn’t just type that sentence.
I’m tentatively ok with claims of the sort that a multiverse exists, although I suspect that too can be dissolved.
Note that in your example, the relevant subset of the multiverse is all the people who are deluding themselves into thinking they typed that sentence. If there’s no meaningful sense in which you’re self located as someone else vs that subset, then there’s no meaningful sense in which you “actually” typed it.
>If they didn’t write the sentence, then they are not identical to me and don’t have to accept that they are me.
Sure, some of those people are not identical to some other people. But how do you know which subset you belong to? A version of you that deluded themselves into thinking they wrote the sentence is subjectively indistinguishable from any other member of the set. You can only get probabilistic knowledge against, i.e. “most of the people in my position are not deluding themselves”, which lets you make probabilistic predictions. But saying “X is true” and grounding that as “X is probable” doesn’t seem to work. What does “X is true” mean here, when there’s a chance it’s not true for you?
I granted your supposition of such things existing. I myself don’t believe any objective external reality exists, as I don’t think those are meaningful concepts.
That there is an external world. Which, in this case, happens to be a multiverse.
You seem to be taking an epistemology-flavoured approach, where realism depends on having a set of facts, rather than a set of things. But even at that, it’s not clear that multiverses imply a lack of facts. If there is a duplicate me somewhere that didn’t just type that sentence, that doesn’t indicate an lack of clarity about what I did , any more than if I had a twin who didn’t just type that sentence.
I’m tentatively ok with claims of the sort that a multiverse exists, although I suspect that too can be dissolved.
Note that in your example, the relevant subset of the multiverse is all the people who are deluding themselves into thinking they typed that sentence. If there’s no meaningful sense in which you’re self located as someone else vs that subset, then there’s no meaningful sense in which you “actually” typed it.
If my supposed counterparts are identical in every way, then there is no confusion about whether they write thc sentence.
If they didn’t write the sentence, then they are not identical to me and don’t have to accept that they are me.
You don’t just need multiverse theory to be true , you need strong claims about transworld identity to be true.
>If they didn’t write the sentence, then they are not identical to me and don’t have to accept that they are me.
Sure, some of those people are not identical to some other people. But how do you know which subset you belong to? A version of you that deluded themselves into thinking they wrote the sentence is subjectively indistinguishable from any other member of the set. You can only get probabilistic knowledge against, i.e. “most of the people in my position are not deluding themselves”, which lets you make probabilistic predictions. But saying “X is true” and grounding that as “X is probable” doesn’t seem to work. What does “X is true” mean here, when there’s a chance it’s not true for you?
Suppose there is no personal identity at all. Then there are still objective facts about what some bunch of atoms somewhere is doing.
Perhaps. It’s not clear to me how such facts could exist, or what claims about them mean.
If you’ve got self locating uncertainty, though, you can’t have objective facts about what atoms near you are doing.
The existence of a set of facts is implied by the existence of a world or worlds. You are supposing be existence of a multiverse, not me.
I can have good-enough knowledge of what atoms near me are doing, because otherwise science wouldn’t work.
Of course, that’s only subjective, but you are the one supposing the existence of a large objective world.
I granted your supposition of such things existing. I myself don’t believe any objective external reality exists, as I don’t think those are meaningful concepts.
They’re in the dictionary.