@Alex
Can't remember for sure, but I think it was Sargon that argued that what gut instinct or intuition is, is basically your brain processing in the background the information you pick you in your life, and constructing some rough models of the world that can guide you unconsciously. An instance of a gut instinct being your brain telling you if something conforms or not with it's currently constructed model.
By this reasoning, of course the models won't be perfect, but they'll be more than adequate for making quick decisions on things.