EPICTETUS. DISCOURSES. Book iv. §6. ¶1.
AND it is impracticable, as well as tedious, to undertake the very thing that Jupiter himself could not do: to convince all mankind what things are really good and evil. Is this granted you? The only thing granted you is to convince yourself, and you have not yet done that; and do you, notwithstanding, undertake to convince others? Why, who hath lived so long with you as you have with yourself? Who is so likely to have faith in you, in order to be convinced by you, as you in yourself? Who is a better wisher, or a nearer friend to you, than you to yourself? How is it, then, that you have not yet convinced yourself? Should not you now turn these things every way in your thoughts ? What you were studying was this: to learn to be exempt from grief, perturbation, and meanness, and to be free. Have not you heard, then, that the only way that leads to this is to give up what doth not depend on choice: to withdraw from it, and confess that it belongs to others? What kind of thing, then, is another's opinion about you? — "Independent on choice." Is it nothing, then, to you? — "Nothing." While you are still piqued and disturbed about it, then, do you think that you are convinced concerning good and evil?