The scientist's interest is concentrated on his experiment, and that is why he finds it hard to do his duty by interrupting it and satisfying his hunger. The student's interest is engrossed in his studies, and the business-man's interest is wholly engaged by his business. It is difficult for them to do their duty in obeying natural impulses, because these run counter to their dominant interests.
We may state, then, the general truth that it is hard for us to do our duty, because Our duty so often conflicts with our dominant interests. The stress and strain of the moral life arise from the conflict of duty and interest. But it is not necessary that duty and interest should always be opposed. Duty and interest may be in perfect accord. And one of the great tasks of the moral teacher, as we shall see more fully later on, is to educate men so that their interests may be in harmony with their duty.
§ 3. Rules of Duty. We have seen that even when we clearly recognise what our duty is, it may be hard to do it. But it is often equally difficult to know what our duty is. What is my duty? Can ethics give any answer to that question? Can ethics give any list of rules, by following which we may be sure always to know what our duty is? In other departments of knowledge and behaviour such systems of rules do exist. The child is early given a set of rules with regard to good manners. In most of the arts there are bodies of rules, which are always or generally true, and by acting in accordance with which the student is likely to turn out good work. Is there anything corresponding to this in ethics? Are there definite rules of conduct, obedience to which
