Basically, it’s not that the presumptuous philosopher is more likely to be right in a given universe, its that there are far more presumptuous philosophers in the large universe. So if we count “how many presumptuous philosophers are correct”, we get a different answer to “in how many universes is the presumptuous philosopher correct”. These things only come apart in anthropic situations.
I have an article on “Anthropic decision theory”. with the video version here.
Basically, it’s not that the presumptuous philosopher is more likely to be right in a given universe, its that there are far more presumptuous philosophers in the large universe. So if we count “how many presumptuous philosophers are correct”, we get a different answer to “in how many universes is the presumptuous philosopher correct”. These things only come apart in anthropic situations.