You find yourself in a room. You know there are only two possible ways you could have gotten into the room, and just a moment earlier you considered them both equally likely:
A: I make 8 identical copies of you and put them in totally identical rooms. A minute passes, then I instantly kill 7 of the copies. (Also, I don’t think it matters but your cognition is deterministic, so you know all 8 copies of you stay perfectly in sync until I kill 7 of them.)
B: I make one copy of you and put it in a room. A minute passes, then I do something that has a 7⁄8 chance of instantly killing the copy.
Now you’ve appeared in the room, but a minute hasn’t passed yet. Regardless of whether A or B is true, you’d experience the same thing either way. Does your estimation of the odds of A:B change?
Now a minute passes and you’re still alive. Des your estimation of the odds of A:B change now?.