People often admonish us to learn the lessons of history, but, even if it were easy to discover what the past was really like, it is nearly impossible to discover its lessons. We are supposed, for example, to learn the lessons of World War I. But what are they? And were we ever to discover what they are, it is not clear that we could ever apply them, for we shall never again have a situation just like World War I. That we should learn the lessons of history figures in the argument in which one of the following ways? ["It is compatible with accepting the argument's conclusion and with denying it.", 'It is a position that the argument simply takes for granted is false.', "It is an assumption that is required in order to establish the argument's conclusion.", 'It expresses the position the argument as a whole is directed toward discrediting.']