... and weight self more than others.
Philosophy, Bayesianism, Religion: Create first principles independently, trust only self.
ethics & metaethics - Trust only self.
Why?
For the latter, because I'm not sure what other choice there is. See the "No Universally Compelling Arguments" posts on Lesswrong.
If the namuH race, who somehow evolved to not use parsimony, told me the more complicated hypothesis is more likely to be true, I'd have no reason to offer then for why they are wrong. But I'd still say they were wrong, because my definition of Wrong is the only one that really matters when it comes down to it (the same way that my values are all that really matter when I'm faced with the Babyeater scenario)
For the ...
For every controversial subject I've heard of, there are always numerous very smart experts on either side. So I'm curious how it is that rational non-experts come to believe one side or the other.
So, what are your meta-arguments for going with one side or the other for any given controversial subject on which you have an opinion?