One of the conditions of a moral action has already been pointed out. This is that all moral rules imply a relation to beings of a similar nature. A second feature is that conduct represents a form of efficiency, it is a special feature of the universal biological fact of adaptation. And the question of why man has a "moral sense" is really on all fours with, and presents no greater mystery than is involved in, the question of why man has digestive organs, and prefers some kinds of food to others. Substantially, the question of why man should prefer a diet of meat and potatoes to one of prussic acid is exactly the question of why society should discourage certain actions and encourage others, or why man's moral taste should prefer some forms of conduct to other forms. The answer to both questions, while differing in form, is the same in substance. Man as we know him is always found as a member of a group, and his capacities, his feelings, and tastes must always be considered in relation to that fact. But considering man merely as an animal, and his conduct as merely a form of adaptation to environment, the plain consideration which emerges is that even as an individual organism he is compelled, in order to live, to avoid certain actions and to perform others, to develop certain tastes and to form certain distastes. To take our previous illustration it would be impossible for man to develop a liking for life-destroying foods. It is one of the conditions of living that he shall eat only that food which sustains life, or that he shall abstain from eating substances which destroy it. But conduct at that stage is not of the kind which considers the reasons for acting; indeed, life cannot be based upon considered action, however much reason may justify the actions taken. Further, as all conscious action is prompted by the impulse to do what is pleasant and to avoid what is unpleasant, it follows, as Spencer pointed out, that the course of evolution sets up a close relation between actions that are pleasurable in the performance and actions that are life preserving. It is one of the conditions of the maintenance of life that the pleasurable and the beneficial shall in the long run coincide.