If I’m in the voting booth, and I suddenly decide to leave the ballot blank, how does that affect anyone else?
It doesn’t affect anyone else in a causal sense, but it does affect people similar to you in a decision-relevant-to-you sense.
Imagine that while you’re in the voting booth, in another identical voting booth there is another person who is an atom-by-atom copy of you (and assume our world is deterministic). In this extreme case, it is clear that you’re not deciding just for yourself. When we’re talking about people who are similar to you rather than copies of you, a probabilistic version of this idea applies.
It doesn’t affect anyone else in a causal sense, but it does affect people similar to you in a decision-relevant-to-you sense.
Imagine that while you’re in the voting booth, in another identical voting booth there is another person who is an atom-by-atom copy of you (and assume our world is deterministic). In this extreme case, it is clear that you’re not deciding just for yourself. When we’re talking about people who are similar to you rather than copies of you, a probabilistic version of this idea applies.
I don’t get it.
Wikipedia’s entry on superrationality probably explains the main idea here better than me.