I'm not sure how you're thinking of this, but think about what's going on in jesscat's "souls" toy picture. In order for U_n to be possible, there must be at least n souls. Since U_n exists for every n, there must be an infinite number of souls - and therefore zero chance that when we pick out exactly one soul for U_1, yours is the soul that gets chosen. Therefore, 'your' probability of existing in U_1 is 0.
This almost works like if each 'soul' was a configuration of a person, and you were one particular configuration - except U_n (and SIA) don't specify that each person has to be unique. Instead, it's more analogous to a particular configuration of a particular chunk of matter - that's one way to put in uniqueness.
The vast majority of possible souls live in chaotic universes. Under this theory, rather than just having a random experience like a Boltzmann brain, you almost certainly have no experience. But having a sensible experience is still astronomically low.
If it's worth saying, but not worth its own post (even in Discussion), then it goes here.
Previous Open Thread
Next Open Thread
Notes for future OT posters:
1. Please add the 'open_thread' tag.
2. Check if there is an active Open Thread before posting a new one. (Immediately before; refresh the list-of-threads page before posting.)
3. Open Threads should be posted in Discussion, and not Main.
4. Open Threads should start on Monday, and end on Sunday.