Since, then, the whole sum of philosophy is directed to ensure living happily, and since men, from a desire of this one thing, have devoted themselves to this study; but different people make happiness of life to consist in different circumstances; you, for instance, place it in pleasure; and, in the same manner you, on the other hand, make all unhappiness to consist in pain: let us consider, in the first place, what sort of thing this happy life of yours is. But you will grant this, I think, that if there is really any such thing as happiness, it ought to be wholly in the power of a wise man to secure it; for, if a happy life can be lost, it cannot be happy. For who can feel confident that a thing will always remain firm and enduring in his case, which is in reality fleeting and perishable? But the man who distrusts the permanence of his good things, must necessarily fear that some day or other, when he has lost them, he will become miserable; and no man can be happy who is in fear about most important matters. No one, then, can be happy; for a happy life is usually called so, not in some part only, but in perpetuity of time; and, in fact, life is not said to be happy at all till it is completed and finished. Nor is it possible for any man to be sometimes happy and sometimes miserable; for he who thinks it possible that he may become miserable, is certainly not happy. For, when a happy life is once attained, it remains as long as the maker of the happy life herself, namely, wisdom; nor does it wait till the last period of a man’s existence, as Herodotus says that Crœsus was warned by Solon.