he who disagrees with me about the chief good, disagrees with me about the whole principle of philosophy. Critolaus wished to copy the ancients; and, indeed, he comes nearest to them in dignity, and his eloquence is preeminent: still he adheres to the ancient doctrine. Diodorus, his pupil, adds to honourableness freedom from pain: he, too, clings to a theory of his own; and, as he disagrees from them about the chief good, he is hardly entitled to be called a Peripatetic. But my friend Antiochus seems to me to pursue the opinions of the ancients with the greatest care; and he shows that they coincided with the doctrines of Aristotle and Polemo.
VI. My young friend Lucius, therefore, acts prudently when he wishes chiefly to be instructed about the chief good; for when this point is once settled in philosophy, everything is settled. For in other matters, if anything is passed over, or if we are ignorant of anything, the inconvenience thus produced is no greater than the importance the matter is of in which the omission has taken place; but if one is ignorant of what is the chief good, one must necessarily be ignorant of the true principles of life; and from this ignorance such great errors ensue that they cannot tell to what port to betake themselves. But when one has acquired a knowledge of the chief ends,—when one knows what is the chief good and the chief evil,—then a proper path of life, and a proper regulation of all the duties of life, is found out.
There is, therefore, an object to which everything may be referred; from which a system of living happily, which is what every one desires, may be discovered and adopted. But since there is a great division of opinion as to what that consists in, we had better employ the division of Carneades, which our friend Antiochus prefers, and usually adopts. He therefore saw not only how many different opinions of philosophers on the subject of the chief good there were, but how many there could be. Accordingly, he asserted that there was no art which proceeded from itself; for, in truth, that which is comprehended by an art is always exterior to the art. There is no need of prolonging this argument by adducing instances; for it is evident that no art is conversant about itself, but that the art itself is one thing, and the object which is proposed to be attained by the art another. Since, therefore, prudence is the art of living, just as medicine is of health, or
