I won’t completely gainsay the gut, as it embodies a few hundred million years’ animal experience, a few million of primate experience, and some hundreds of thousands of human experience. On the other hand, it also embodies those same periods’ accumulated kruft that was not filtered out by the culling algorithm of evolution, as well as wisdom that might have made sense for a member of a fifty-primate band in the Serengeti, but might in fact be nonsense for an urbanite in the First world. Never, ever, trusting someone with whom you didn’t grow-up comes to mind, as does never trusting people with deformed faces that match a normal person’s aggression or deception faces, as does believing that someone will make a good life-partner completely on the basis of her or his high degree of facial symmetry.
Another problem with gut instinct is that we are very resistant to seeing when it is wrong. I think that this is the origin of the misleading feeling that it’s always right——that is, your gut continues to trust itself even in the face of evidence. For example, I used to believe that I could very accurately assess people within a minute or so of meeting them. With experience and analysis, I have come to see that often what was really going on was my refusal to really look again at other people after that initial impression; my gut saw no reason to pose the question to anyone but itself——and you should never trust any being that claims to be the ultimate authority on everything, always, and who is neither Prof. Irwin Corey or John Hodgman, his modern avatar for the hep.
(The “rational” mind can also be subject to this bias, but more often I see the bias supervene in people who have mostly deprecated that subsystem in favour of the gut, usually without noticing that they have transferred control of the “thinking” in mid-thought. See: “snarl word”.)
To indulge in bad language and to almost quote Ken Macleod: ‘Screw the force; trust the targetting [sic] computer.’