Ante-Nicene Fathers, Vol VII:
Lactantius: Chap. VII.—Of moral philosophy, and the chief good

Chap. VII.—Of Moral Philosophy, and the Chief Good.

Let us now pass to the other part of philosophy, which they themselves call moral, in which is contained the method of the whole of philosophy, since in natural philosophy there is only delight, in this there is utility also. And since it is more dangerous to commit a fault in arranging the condition of life and in forming the character, greater diligence must be used, that we may know how we ought to live. For in the former subject 385 some indulgence may be granted: for whether they say anything, they bestow no advantage; or if they foolishly rave, they do no injury. But in this subject there is no room for difference of opinion, none for error. All must entertain the same sentiments, and philosophy itself must give instructions as it were with one mouth; because if any error shall be committed, life is altogether overthrown. In that former part, as there is less danger, so there is more difficulty; because the obscurity of the subject compels us to entertain different and various opinions. But in this, as there is more danger, so there is less difficulty; because the very use of the subjects and daily experiments are able to teach what is truer and better. Let us see, therefore, whether they agree, or what assistance they give us for the better guidance of life. It is not necessary to enlarge on every point; let us select one, and especially that which is the chief and principal thing, in which the whole of wisdom centres and depends. 386 Epicurus deems that the chief good consists in pleasure of mind, Aristippus in pleasure of the body. Callipho and Dinomachus united virtue with pleasure, Diodorus with the privation of pain, Hieronymus placed the chief good in the absence of pain; the Peripatetics, again, in the goods of the mind, the body, and fortune. The chief good of Herillus is knowledge; that of Zeno, to live agreeably to nature; that of certain Stoics, to follow virtue. Aristotle placed the chief good in integrity and virtue. These are the sentiments of nearly all. In such a difference of opinions, whom do we follow? whom do we believe? All are of equal authority. If we are able to select that which is better, it follows that philosophy is not necessary for us; because we are already wise, inasmuch as we judge respecting the opinions of the wise. But since we come for the sake of learning wisdom, how can we judge, who have not yet begun to be wise? especially when the Academic is close at hand, to draw us back by the cloak, and forbid us to believe any one, without bringing forward that which we may follow.  

Footnotes

Natural philosophy.  

The hinge of wisdom altogether turns.