There is a view, advocated, _e.g._ by Dr. G. E. Moore, that “good” is an indefinable notion, and that we know _a priori_ certain general propositions about the kinds of things that are good on their own account. Such things as happiness, knowledge, appreciation of beauty, are known to be good, according to Dr. Moore; it is also known that we ought to act so as to create what is good and prevent what is bad. I formerly held this view myself, but I was led to abandon it, partly by Mr. Santayana’s _Winds of Doctrine_. I now think that good and bad are derivative from desire. I do not mean quite simply that the good is the desired, because men’s desires conflict, and “good” is, to my mind, mainly a social concept, designed to find an issue from this conflict. The conflict, however, is not only between the desires of different men, but between incompatible desires of one man at different times, or even at the same time, and even if he is solitary, like Robinson Crusoe. Let us see how the concept of “good” emerges from reflection or conflicts of desires. We will begin with Robinson Crusoe. In him there will be conflicts, for example, between fatigue and hunger, particularly between fatigue at one time and foreseen hunger at another. The effort which he will require in order to work when he is tired with a view to providing food on another occasion has all the characteristics of what is called a moral effort: we think better of a man who makes the effort than of one who does not, and the making of it requires self-control. For some reason, this sort of thing is called, not morals, but “morale”; the distinction, however, seems to me illusory. Robinson Crusoe is bound to realise that he has many desires, each of which is stronger at one time than at another, and that, if he acts always upon the one that is strongest at the moment, he may defeat others that are stronger in the long run. So far, only intelligence is involved; but one may assume that, with the progress of intelligence, there goes a growing desire for a harmonious life, _i.e._ a life in which action is dominated by consistent quasi-permanent desires. Again: some desires, in addition to the desire for a harmonious life, are more likely to lead to harmony then certain other desires. Intellectual curiosity, _e.g._ affords a mild diffused satisfaction, whereas drugs provide ecstasy followed by despair. If we arrive unexpectedly in Robinson Crusoe’s island and find him studying botany, we shall think better of him than if we find him dead drunk on his last bottle of whisky. All this belongs to morals, although it is purely self-regarding.