The editor suggested my writing an article on the question whether it was possible to provide an ethics based upon principles which would be agreed to by all enlightened men, and he further suggested that I should begin the article by stating clearly what morality is. That is a somewhat difficult task, because while “morality” might be defined as “living as one ought,” it is a very disputable question whether and how this “ought” is itself to be defined, and I could not undertake to deal with this question by the way as an introduction to an article on something else. It is, however, clear that there is another sense of “ought” besides the strictly moral sense. We do use the term in cases where it does not entail that a man is neglecting his moral duty if he does not do what he “ought.” For instance we say: “You ought to have seen that film,” “You ought not to have made that move,” “You ought to have seen through that argument,” even “Hitler ought to have invaded England after Dunkirk” where we should have regarded it as the reverse of a good thing if he had done what we say he ought. In none of these cases are we asserting a moral obligation. For we do not ordinarily regard people as under a moral obligation to seek their own pleasure, nor to make certain moves in a game, and while we should say that in matters of serious concern a person is morally obliged to do his best to form a true view as to the merits of a relevant argument, we should not say that he was morally obliged actually to form a true view, for this does not depend solely on his will. And in the fourth instance the action is one which we should think morally wrong rather than morally obligatory. What is there in common between “ought” as used in these cases and the moral “ought”? It is that in each case the action fits the situation, either wholly, or with certain limitations, as in the last instance where we presumably mean that to invade England would have fitted in better with Hitler's ends in the given environment than did the policy Hitler actually adopted.