  Why do we think of the moral person as the person of principle, and why do we think of moral judgement as subject to this sort of consistency constraint? (As we will see later, there are other forms that the consistency constraint could have taken.) The answer, I think, is that we suppose that without moral principles there could be no such thing as the difference between right and wrong. Rightness and wrongness are peculiar properties, and the only way that an action can get them is by being related to a principle in one way or another. So unless there are principles saying which sorts of actions are right and which wrong, none would be right and none wrong. If this were so, it would hardly be surprising that the good moral judge would be the person capable of following in her mind the way in which actions get to be right or wrong, which requires knowing the relevant principles and seeing that they have this effect here and that effect there. And it would be hardly surprising that consistency in judgement would amount to no more than applying similar principles to similar cases.