A brief note to the (surprisingly numerous) egoists/moral nihilists who commented so far. Can’t you folks see that virtually all the reasons to be skeptical about morality are also reasons to be skeptical about practical rationality? Don’t you folks realize that the argument that begins questioning whether one should care about others naturally leads to the question of whether one should care about oneself? Whenever I read commenters here proudly voicing that they are concerned with nothing but their own “persistence odds”, or that they would willingly torture others to avoid a minor discomfort to themselves, I am reminded of Kieran Healy’s remarks about Mensa, “the organization for highly intelligent people who are nevertheless not quite intelligent enough not to belong to it.” If you are so smart that you can see through the illusion that is morality, don’t be so stupid to take for granted the validity of practical rationality. Others may not matter, but if so you probably don’t either.
Morality is a tool for self-interest. Acting cooperatively was good for you in the ancestral enviroment, so people who had strong moral feelings did better. People who are under the illusion that action “should” have a rational basis construct rationalizations for morality, because they want to act morally for reasons that have nothing to do with rationality.
Self-interest is no more rational that moral behaviour. People also seek self-interest because that’s just how their genes have wired their monkey brains to work.
A being of pure rationality and no desires would do nothing. Many apparently people think that it could come to a conclusion of what to do by discovering some universal “should” by rational deliberation, but that’s wrong.
This is existentialism 101, I know, but it’s also true.
On the other hand,I can’t imagine what would make me skeptical about practical rationality. The point of it is that it works in predicting my experience, and I seem to desire to know about that which determines my experience. Showing that practical rationality is wrong is an empirical matter, showing that it doesn’t work.