Epictetus took advantage of a visit from an inspector who was Epicurean. Getting right to the point, Epictetus asked him "what is the best thing in the world" / "which is best" (v. 1-2, p. 156).
Both Epictetus and the Epicurean agreed that the flesh - the body is not the best good (v. 3, p. 156).
The next agreed that the best good lies within the mind (v. 4, p. 156) and specifically what lies within our "sphere of choice" (v. 5. p. 156).
Continuing, "does the pleasure of the mind lie within the sphere of choice?" to which the Epicurean said "it does" (v. 6. p. 156).
Epictetus then asks what is the cause of this pleasure of the mind. Can the mind just create the pleasure by itself, or is there some cause of it? The Epicurean agreed that there must be some cause before the pleasure ensues (v. 7, p. 156).
And on this point Epictetus begins to instruct the Epicurean. In essence the question is: can something 'not good' cause pleasure which is 'good'? On this, they both agree. If your pleasure is to be good, the thing on which it is based must also be good ... they both agree with this concept. I wish to quote Robertson on this particular part, as he does a great job explaining this specific passage:
He proceeds to ask him about his assumptions concerning the good, and then to expose apparent contradictions in his position. He leads the Epicurean into a position where he appears to admit that pleasure must have some object, and for it to be good, its object must also be good. The goodness of pleasure depends upon the goodness of the thing we take pleasure in. For example, to take pleasure in atrocities would be bad. They agree the highest good must be the moral purpose (prohairesis) of the soul, i.e., the seat of wisdom and virtue, which most people agree is what we find most praiseworthy in man.However, this goes against the Epicurean philosophy of "the pleasure of the mind is pleasure in bodily things, and these [external] pleasures thus come to be what is of primary value, and the essence of the good" (v. 8, p. 156).
The next point Epictetus makes is to show the Epicurean that although they teach that to obtain the Good, they ought to seek pleasure by stealing, while not getting caught, they still do not steal. Why is that? Because "it is impossible to give our assent to what appears to be false" (v. 15, p. 157). The same can be said of securing massive amounts of wealth, seducing your neighbor's wife and even killing her husband (v. 15-16, p. 157).
The Epicureans preach "shameful doctrines" while "acting nobly" and the Stoics preach "what is fine and noble, but do what is shameful" (v. 18, p. 157).
The next folly of Epicureanism that Epictetus points out has to deal with the discipline of action. Whereas the Stoics adhere to a cosmopolitan view of the world, in that we each have a duty to those closest to us which then expands to the community and the whole world, the Epicureans have a more selfish motive and one that is unsustainable as a community. To maximize pleasure and minimize pain, people would choose to not marry, nor have children, nor perform civic duties. Consequently, society would cease to exist if everyone adhered to Epicureanism (see v. 19-20, p. 157).
And if the Epicurean city official could not fully understand Epictetus' point, Epictetus makes it crystal clear what one ought to do with regard to the community: "keep your hands off other people's property, regard no woman as beautiful apart from your own wife, and regard no boy as beautiful, nor any piece of silverware or goldware. You should seek out doctrines that are consistent with that pattern of behavior" (v. 21-22, p. 158).
He further emphasizes this when he says our actions should be "fulfilling one's role as a citizen, marrying, having children, honouring God, taking care of one's parents, and, in a word, having our desires and aversions, and our motives to act and or not to act, as each of them ought to be, in accordance with our nature. And what is our nature? To be people who are free, noble-minded, and self-respecting" (v. 26-27, p. 158).
And just because Caesar signed a piece of paper certifying that this Epicurean is a judge, does not make him a good judge anymore than if Caesar had given him credentials that he's a judge of music (v. 30, p. 158). No, what makes a good judge is someone who will govern people "as rational beings by showing [them] what is in their interest" and that he must earn their respect by being a good person himself. The judge should act in a way so that people would admire him and want to emulate him (see v. 34, p. 159).