I don't think that b is necessarily an immediate entailment of rationality, but a condition that can be met simultaneously with a and c. The post presents a situation where c is satisficed only through a and b. (It does not take much finagling to suppose that a lonesome mountain man existence in a world ruled by barbarians is inferior in fuzziness and utilons relative to the expectation of the world where a b and c are held to be true.)