One particularly important thing I got out of this post was crystallizing a complaint I sometimes have about people using anthropic reasoning. If someone says there’s trillion-to-1 evidence for (blah) based on anthropics, it’s actually not so crazy to say “well I don’t believe (blah) anyway, based on the evidence I get from observing the world”, it seems to me.
Or less charitably to myself, maybe this post is helping me rationalize my unjustified and unthinking gut distrust of anthropic reasoning :-P
Anyway, great post.
ADDED 3½ YEARS LATER: Whoops, that’s not a good argument. Generically in Bayesian rationality, if you encounter trillion-to-1 evidence for X over Y, and then later encounter trillion-to-1 evidence for Y over X, then the wrong thing to do is apply Bayes’s rule and revert to the prior, whereas the right thing to do is to recognize that this situation should basically never happen, and therefore it’s overwhelmingly likely that at least one of those two purported pieces of evidence is actually wrong or misinterpreted. (H/t something Eliezer wrote, probably.)
One particularly important thing I got out of this post was crystallizing a complaint I sometimes have about people using anthropic reasoning. If someone says there’s trillion-to-1 evidence for (blah) based on anthropics, it’s actually not so crazy to say “well I don’t believe (blah) anyway, based on the evidence I get from observing the world”, it seems to me.
Or less charitably to myself, maybe this post is helping me rationalize my unjustified and unthinking gut distrust of anthropic reasoning :-P
Anyway, great post.
ADDED 3½ YEARS LATER: Whoops, that’s not a good argument. Generically in Bayesian rationality, if you encounter trillion-to-1 evidence for X over Y, and then later encounter trillion-to-1 evidence for Y over X, then the wrong thing to do is apply Bayes’s rule and revert to the prior, whereas the right thing to do is to recognize that this situation should basically never happen, and therefore it’s overwhelmingly likely that at least one of those two purported pieces of evidence is actually wrong or misinterpreted. (H/t something Eliezer wrote, probably.)