Chisholm recognized, however, that any system based on those assumptions (and making use of the standard connectives) would be unable to express certain familiar and important facts. Among these is the fact that in many cases our moral obligations depend essentially upon our moral failings. For example, a person might have a moral obligation to apologize for some misbehavior — yet obviously he would not be apologizing in a morally perfect world, since in such a world he would not have misbehaved in the first place. Presumably, there are no apologies in a morally perfect world. If we let ‘O(Smith apologizes)’ express the idea that there is a moral obligation for Smith to apologize, then the imagined semantics would apparently be unable to account for the possibility that the statement could be true. Smith does not apologize for anything at any morally perfect world.