Very true! But part of knowing that you don't know is recognizing when you're in unfamiliar territory. Being able to say "this example doesn't look like what I'

Very true! But part of knowing that you don't know is recognizing when you're in unfamiliar territory. Being able to say "this example doesn't look like what I've seen before, and therefore I'm not as sure of my response." Algorithms which can express uncertainty /should be/ more robust to domain errors.