Yes, I do think that rationalism is intimately involved with self-doubt, and that many people are wholly unaware of the possibility that others with whom they disagree may be right rather than wrong. But I also think that there is such a thing as truth, and that it would be an error to believe that no one is stupid or acts irrationally.

But possibly I just don't understand your point. Are you arguing against the precepts of LessWrong, or against the case that Kenneth is making showing its limitations? Are you arguing that rationality is (or should be) synonymous with evolutionary fitness rather than truth? That believing things that are factually true can be irrational?

If you're up for watching depressing but incredibly insightful documentaries, I'd recommend "Stevie" (http://movies.netflix.com/WiMovie/Stevie/60027209?trkid=2361...) as one that might change your mind on whether "no one is stupid". It's a brilliant movie of stupid people making their way in the world, with as much grace as they can manage. The scary part for me was that the self-explanations of the (medically) retarded characters vacillate between sounding simplistic and fully aware. I think the rational conclusion would be that it's awfully hard to tell which rung one is standing on, and whether others are above or below it. But I don't think it would be rational to conclude that "everyone's pretty much the same".