I am perplexed by Alexander George's recent posting (http://www.askphilosophers.org/question/2854). He says "Your observation that we sometimes take pleasure in beliefs even if they have been irrationally arrived at seems correct but beside the point: it speaks neither to the truth of (1) nor to that of (2)." (2), in this case, is "(2) that actions guided by false beliefs are not likely to get us what we want. "
I believe the science of psychology has shown us that we form many beliefs entirely irrationally. The mechanism for their formation is often a defense mechanism. The purpose of their formation is often to hide some truth about ourselves from ourselves - to hide some unpleasant information that we would have gleaned had we formed our belief rationally.
I just can't see how the above information is "beside the point". The point is: 1) I want to be happy. 2) My beliefs are formed irrationally in order to reach that desired end. Perhaps what is beside the point is that the belief-forming...
Just a footnote to Mark Collier's helpful post. I actually said that irrationally formed beliefs are not likely to lead to actions which get us what we want (rather than cannot get us what we want). And that claim is enough to explain why we should in general care a lot about forming our beliefs in a rational way . Which in turn is enough to counter the original questioner's worry that philosophy "uses as its main tool a mechanism [rational thought] that is the opposite of what is most important to us": in general , rational belief-formation matters for getting whatever is important to us. Even if pockets of irrationality, episodes of self-deception, etc. can -- by good fortune -- happen to promote our welfare.