 By using the notion of an informal public system, we can improve the basic schema for definitions of “morality” in the normative sense. The old schema was that morality is the code that all rational persons, under certain specified conditions, would endorse. The improved schema is that morality is the informal public system that all rational persons, under certain specified conditions, would endorse. Some theorists might not regard the informal nature of the moral system as definitional, holding that morality might give knowable precise answers to every question. This would have the result that conscientious moral agents often cannot know what morality permits, requires, or allows. Some philosophers deny that this is a genuine possibility.