The penny has just dropped! When I first encountered LessWrong, the word 'Rationality' did not stand out. I interpreted it to mean its everyday meaning of careful, intelligent, sane, informed thought (in keeping with 'avoiding bias'). But I have become more and more uncomfortable with the word because I see it having a more restricted meaning in the LW context. At first, I thought this was an economic definition of the 'rational' behaviour of the selfish and unemotional ideal economic agent. But now I sense an even more disturbing definition: rational as opposed to empirical. As I use scientific evidence as the most important arbiter of what I believe, I would find the anti-empirical idea of 'rational' a big mistake.