ever come to an end. It is clear that merely by failing to provide for the needs of his son, that is, by a simple omission, the father would injure him, indeed jeopardise his life. Children's duty towards their parents is not so direct and imperative. It rests on the fact that, as every duty involves a right, parents also must have some just claim on their issue. This is the foundation of the duty of filial obedience, which, however, in course of time ceases simultaneously with the right out of which it sprang.

It is replaced by gratitude for that which was done by father and mother over and above their strict duty. Nevertheless, although ingratitude is a hateful, often indeed a revolting vice, gratitude cannot be called a duty; because its omission inflicts no injury on the other side, and is therefore no wrong.