If you're going to worry about things like that if big world immortality is true, you can just worry about them anyway, because the only thing that you will ever observe (even if big world immortality is false) is that you always continue to survive, even when other people die, even from things like nuclear war.
Your observations will always be compatible with your personal immortality, no matter what the truth is.
Well, sort of, but I still think there is an important difference in that without big world immortality all the survival scenarios may be so unlikely that they aren't worthy of serious consideration, whereas with it one is guaranteed to experience survival, and the likelihood of experiencing certain types of survival becomes important.
Let's suppose you're in a situation where you can sacrifice yourself to save someone you care about, and there's a very, very big chance that if you do so, you die, but a very, very small chance that you end up alive but crip...
If it's worth saying, but not worth its own post (even in Discussion), then it goes here.
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