Similar relations exist for the sense of disgust, which is allied to the sense of shame. Shame is felt in the performance of an action disgusting to others, if against one's will one is watched in the process. Defaecation is usually effected in some retired place: in the onlooker, defaecation arouses disgust; whilst by the person defaecating, if he knows that he is being observed, shame is felt. Normal sexual intercourse between a man and a woman, objectively regarded, is a no less unaesthetic act than pseudo-coitus between two men. None the less, in most persons, the sight of the former act arouses less disgust than that of the latter. This difference depends upon the fact that by most persons homosexual intercourse is also felt to be immoral. In this relationship between the sense of disgust and immorality, it is often impossible to determine what is primary and what is secondary. A mutual retroaction occurs: the sense of disgust is increased, because the act is regarded as immoral; and, on the other hand, a strong sense of disgust may increase the perception of immorality. The same mutual relationships with the ideas of morality are found in connexion with the sense of shame. Beyond question, the sentiments of shame and of disgust are closely connected with the ideas of custom and morality; for shame and disgust arise especially in connexion with matters which conflict with our ideas of morality. It will, therefore, readily be understood that in moral education it is of the greatest importance what are the processes in connexion with which the instructor seeks to arouse the sentiments of shame and disgust; and, on the other hand, it is obvious that the ideas of morality induced by education, favour the development, in certain specific relationships, of the sentiments of shame and disgust.