"Gladness, in some instances, springs from a natural buoyancy of temperament, and is quite consistent with shallowness and superficiality of character. In other cases it is coincident with the swift flow of the currents of the blood, and ceases when the stream flows more slowly and begins to stagnate. Or it is due to gifts which an exceptional good fortune showers into the laps of favoured mortals. Gladness of this sort comes with happiness and departs with it. But the purified gladness of which I speak is not dependent on these accidents. It is the mark of the ripest wisdom, and is based on the conviction, gained through experience, that life is worth living, that the victory is assured, and that the ends we pursue are of such excellence as to be incapable of ultimate defeat."