Maybe someone will prove me wrong (and thus irrational), but I believe you're mistaken about what "rational" means: The definitions and synonyms for rationalit

Maybe someone will prove me wrong (and thus irrational), but I believe you're mistaken about what "rational" means: The definitions and synonyms for rationality (found, e.g., with Google Define) are heavily clustered around reasoning, i.e. the ability to reach valid conclusions from your premises. Nowhere do I see mention that your information had to correspond to reality. If I were to believe with great certainty that my wife is an alien breeding a cluster of biological weapons that will destroy all of humanity, and assuming that I want to prevent this from happening, reason would compel me to kill her. It would be a completely rational act. People get this wrong because holding such beliefs is typical for crazy (= irrational) people. Because to _arrive_ at this belief, unless it was imposed on me through drugs, brain damage or brainwashing, would involve some major failures of reasoning at some _earlier_ point. I would have to e.g. believe that I was privy to information that the rest of the world didn't have, which is a pretty unreasonable thing to believe, given what every adult knows about how the world works. Less radical example: At some point in history, it was considered common knowledge that the world is flat, and seafaring too far in any given direction runs the risk of falling off the edge. So sailors were afraid to sail too far. Was this fear irrational? Not at all! Based on the best human knowledge at the time, people had good reason to be afraid. That fear would be irrational for a well-informed person of our time, sure, but only because we meanwhile have access to better information. Hypothetical: Maybe there's a meteor headed for Earth, due to destroy us all in a month. Let's say for now that this is reality - but we don't know it because NASA hasn't seen this meteor yet. If rationality were based on absolute reality, then the rational thing for us to do would be to build spaceships or blow our life savings on drugs and hookers. But that's silly, because we can only base the well-reasoned-ness of our actions on what we know. And for lack of omniscience, everyone's knowledge will always be imperfect, and with perfect reasoning (= rationality) our actions can only be as good as the information we have.