 Just as our beliefs about empirical matters can be mistaken in any given case, and we can make genuine discoveries about empirical reality, just so with rationality. Clearly this claim is much more plausible with the stronger conception of rationality that McDowell is urging than the weaker conception limited to mere deductive relations. McDowell goes on to argue that because of this feature, we must be open to the possible reinterpretation of a person’s behavior and psychological states in light of our changing conception of rationality, and how it changes cannot be anticipated in advance so that rationality could be captured in a permanent set of principles from which strict laws could be fashioned. For this reason, rationality is uncodifiable. According to McDowell, this is what underlies mental anomalism.