6. Just as when one goes on a journey, he need not think of his destination at every step of his way, and yet all his steps are directed towards his destination: so men do not think of happiness in all they do, and yet all they do is referred to happiness. Tell a traveller that this is the wrong way to his destination, he will avoid it; convince a man that this act will not be well for him, will not further his happiness, and, while he keeps that conviction principally before his eyes, he will not do the act. But as a man who began to travel on business, may come to make travelling itself a business, and travel for the sake of going about; so in all cases there is a tendency to elevate into an end that which was, to start with, only valued as a means to an end. So the means of happiness, by being habitually pursued, come to be a part of happiness. Habit is a second nature, and we indulge a habit as we gratify nature. This tendency works itself to an evil extreme in cases where men are become the slaves of habit, and do a thing because they are got into the way of doing it, though they allow that it is a sad and sorry way, and leads them wide of true happiness. These instances show perversion of the normal operation of the will. _Readings_.--St. Thos., 1a 2æ, q. 1, art. 4, in corp.; _ib_., q. 1, art. 6, 7; _ib_., q. 5, art. 8; Ar., _Eth_., I., vii., 4, 5. SECTION II.--_Definition of Happiness_. 1. Though all men do all things, in the last resort, that it may be well with them and theirs, that is, for happiness vaguely apprehended, yet when they come to specify what happiness is, answers so various are given and acted upon, that we might be tempted to conclude that each man is the measure of his own happiness, and that no standard of happiness for all can be defined. But it is not so. Man is not the measure of his own happiness, any more than of his own health. The diet that he takes to be healthy, may prove his poison; and where he looks for happiness, he may find the extreme of wretchedness and woe. For man must live up to his nature, to his bodily constitution, to be a healthy man; and to his whole nature, but especially to his mental and moral constitution, if he is to be a happy man. And nature, though it admits of individual peculiarities, is specifically the same for all. There will, then, be one definition of happiness for all men, specifically as such.