To believe that you’re a one in a million case (e.g. in the first or last millionth of all humans), you need 20 bits of information (because 2^20 is about 1000000).
So on the one hand, 20 bits can be hard to get if the topic is hard to get reliable information about. But we regularly get more than 20 bits of information about all sorts of questions (reading this comment has probably given you more than 20 bits of information). So how hard this should “feel” depends heavily on how well we can translate our observational data into information about the future of humanity.
Extra note: In the case that there are an infinite number of humans, this uniform prior actually breaks down (or else naively you’d think you have a 0.0% chance of being anyone at all), so there can be a finite contribution from the possibility that there are infinite people.
To believe that you’re a one in a million case (e.g. in the first or last millionth of all humans), you need 20 bits of information (because 2^20 is about 1000000).
So on the one hand, 20 bits can be hard to get if the topic is hard to get reliable information about. But we regularly get more than 20 bits of information about all sorts of questions (reading this comment has probably given you more than 20 bits of information). So how hard this should “feel” depends heavily on how well we can translate our observational data into information about the future of humanity.
Extra note: In the case that there are an infinite number of humans, this uniform prior actually breaks down (or else naively you’d think you have a 0.0% chance of being anyone at all), so there can be a finite contribution from the possibility that there are infinite people.