Duties are universally measured by relations. Is a man a father? The precept is to take care of him, to yield to him in all things, to submit when he is reproachful, when he inflicts blows. But suppose that he is a bad father. Were you then by nature made akin to a good father? No; but to a father. Does a brother wrong you? Maintain then your own position toward him, and do not examine what he is doing, but what you must do that your will shall be conformable to nature. For another will not damage you, unless you choose: but you will be damaged then when you shall think that you are damaged. In this way, then, you will discover your duty from the relation of a neighbor, from that of a citizen, from that of a general, if you are accustomed to contemplate the relations.