I think we're all rationalists here in that we want our beliefs to be based on reason and empirical evidence rather than superstition or arbitrary assertion. But it's not always clear how to interpret the evidence, or even what counts as evidence at all.
I've been reading a lot of books on how the mind works, and it seems to me clear that we have at least some instinctual beliefs which are the result of evolutionary pressure. For example, people (and primates in general) have an inborn fear of snakes. People who live their whole lives on islands where there are no snakes are afraid of snakes when they first encounter them, and chimpanzees in zoos who have never encountered snakes will freak out if they are exposed to hoses which resemble snakes.
Does it seem reasonable that a widespread, seemingly inborn belief that certain things are good, bad, or dangerous is in fact fairly decent evidence (not proof) that those things are in fact good, bad, or dangerous, and that beliefs that such things are good or bad or dangerous are in fact based on empirical data?