are according to nature; but this does not always depend on ourselves, for it is perfected both out of that kind of life which is bounded by virtue, and out of those things which are according to nature, and which are not in our own power. But this chief good, which is understood in the third signification of the definition, and that life which is passed in conformity with that good, can happen to the wise man alone, because virtue is connected with it. And that summit of good, as we see it expressed by the Stoics themselves, was laid down by Xenocrates and by Aristotle; and so that first arrangement of the principles of nature, with which you also began, is explained by them in almost these very words. VII. All nature desires to be a preserver of itself, in order that it may be both safe itself, and that it may be preserved in its kind. They say that for this end arts have been invented to assist nature, among which that is accounted one of the most important which is the art of living so as to defend what has been given by nature, and to acquire what is wanting; and, at the same time, they have divided the nature of man into mind and body. And, as they said that each of these things was desirable for its own sake, so also they said that the virtues of each of them were desirable for their own sake. But when they extolled the mind with boundless praises, and preferred it to the body, they at the same time preferred the virtues of the mind to the goods of the body. But, as they asserted that wisdom was the guardian and regulator of the entire man, being the companion and assistant of nature, they said that the especial office of wisdom was to defend the being who consisted of mind and body,—to assist him and support him in each particular. And so, the matter being first laid down simply, pursuing the rest of the argument with more subtlety, they thought that the goods of the body admitted of an easy explanation, but they inquired more accurately into those of the mind. And, first of all, they found out that they contained the seeds of justice; and they were the first of all philosophers to teach that the principle that those which were the offspring should be beloved by their parents, was implanted in all animals by nature; and they said, also, that that which precedes the birth of offspring, in point of time,—namely, the marriage of men and women,—was a bond of union suggested by nature, and that this was the root from which the friendships between relations sprang. And, beginning with these first principles, they proceeded to investigate the origin and progress of all the virtues; by which course a great magnanimity was engendered, enabling them easily to resist and withstand fortune, because the most important events were in the power of the wise man; and a life conducted according to the precepts of the ancient philosophers was easily superior to all the changes and injuries of fortune.