In my search in trying to fully understand this passage, I found that Massimo Pigliucci has done a fine job explaining it. I won't bother replicating his effort! Below is the text from his blog post.
This must be Epictetus’ week. Well, for me it’s actually Epictetus’ year, since I decided that the book I’m writing, How To Be a Stoic (to be published by Basic Books in spring ’17) will be organized as an indirect conversation between myself and the slave-turned-teacher, who will guide me and my readers in a breezy exploration of Stoicism. (My original idea was to use Seneca, but I changed my mind.)
Anyway, the other day I was re-reading Discourses II.20, entitled “Against followers of Epicurus and of the Academy,” and I was reminded once again of how forceful Epictetus’ prose can be, and of how intense the intellectual debate among Hellenistic schools really was.
The chapter is in the same spirit of the discussion immediately preceding it, in II.19, which uses the so-called “Master Argument” to make the point that theory is fine in philosophy, as long as it doesn’t get in the way of practice. In II.20 Epictetus exploits his disagreement with both the Epicureans and the (skeptical) Academics to remind his students of the same thing. He begins with what he probably saw as the sophistry of the Academics:
“Even those who contradict propositions that are true and evident are obliged to make use of them. And indeed one may almost give as the strongest proof that a thing is evident that even he who contradicts it finds himself obliged to make use of it. For instance, if one should deny that any universal statement is true, plainly he cannot help asserting the contrary. ‘No universal statement is true.’ Slave, this is not true either: for what else is your assertion than, ‘If a statement is universal, it is false?’ Again, if one comes forward and says, ‘Know that nothing is knowable, but that everything is unprovable,’ or another says, ‘Believe me, and it will be to your advantage; you ought not to believe a man at all’; or again, if another says, ‘Learn from me, man, that it is impossible to learn anything; I tell you this, and will teach you, if you will.’ What difference is there between such persons and–whom shall I say?–those who call themselves Academics?”
The sarcasm is palpable, and it could be directed just as well to some contemporary philosophers of my acquaintance. (I’m not kidding: I just reviewed a chapter by a colleague for a book I’m putting together on the concept of scientism, which is entirely based on very clever and yet completely useless utterances. I kept reaching for Epictetus to help restore my Stoic equanimity…)
The strategy here is to show that the Academics’s positions are self-defeating, based as they are on paradoxes of language and nothing more. This is about the same approach that is often used nowadays against extreme versions of certain philosophical doctrines. If you are a strict logical positivist, for instance, and you believe that only utterances that can be verified empirically are sensible (the rest literally being nonsense), then what sort of empirical evidence would you adduce in support of that verifiability principle itself?
Or suppose you are an extreme postmodernist, claiming that all knowledge is relative, so that no particular position on anything is more rationally defensible than any other. Does that include also your version of postmodernism? And so forth…
Epictetus then turns to Epicurus:
“So too Epicurus, when he wishes to get rid of the natural fellowship of men with one another, makes use of the very principle of which he is getting rid. For what does he say? ‘Men, be not deceived, be not misled or deluded. There is no natural fellowship of rational beings with one another: believe me. Those who state the contrary deceive you and mislead your reason.’ What concern, then, is it of yours? … Man, why do you take thought for our sake, why do you keep awake for us, why do you light your lamp, why do you rise early, why do you write such big books? … for this is the life of which you pronounce yourself worthy: eating, drinking, copulation, evacuation, and snoring. What does it matter to you, what opinions others will hold on these matters, or whether they are right or wrong? … What, then, was it that roused Epicurus from his slumbers and compelled him to write what he wrote?”
Epictetus is essentially accusing Epicurus of disbelieving his own philosophy. If it is truly the case, as Epicurus apparently maintained, that there is no fellowship of humanity, that people care (and ought to care) only for mild pleasures and the avoidance of pain, why on earth go through the manifestly painful exercise of writing entire books to convince your fellow humans that they are wrong in what they are doing? Why does the Epicurean care to begin with?
Because, says Epictetus, it is in the nature of being human to care about others, despite loud protestations to the contrary:
“What! We speak of Orestes pursued by the Furies and roused from his slumbers, but are not the Furies and Torments that beset Epicurus more exacting? They roused him from his sleep and would not allow him to rest, but compelled him to announce his miseries, as madness and wine compel the priests of Cybele. So powerful and unconquerable a thing is human nature. How can a vine be moved to act, not as a vine but as an olive, or again an olive not as an olive but as a vine? It is impossible, inconceivable.”
Why, exactly, is Epictetus so worked up about this? (As much as a Stoic can be worked up about things, anyway…) He doesn’t care to show that the Academics or the Epicureans are wrong. He cares about philosophy being useful rather than harmful to people and society at large:
“Bravo, philosopher! Stick to your task, persuade our young men, that we may have more to agree with you and share your views. These, no doubt, are the arguments which have brought well-governed cities to greatness, these are the arguments which made Lacedaemon, these are the convictions which Lycurgus wrought into the Spartans by his laws and training: that slavery is no more shameful than noble, and freedom no more noble than shameful! For these beliefs no doubt those who died at Thermopylae died! And for what principles but these did the Athenians give up their city?”
First of all, notice the passion here! And remember it, next time someone accuses (again) the Stoics of being detached and emotionless robots. Notice also, again, the deployment of sarcasm as a way to make his students pay attention. And finally that Epictetus here is again rejecting epistemic and moral relativism, positions that are still surprisingly common not just in some quarters of the (modern) academy, but among the population at large.
He then goes back to commonsense, again coupled with a good dose of sarcasm:
“Man, what are you doing? You convict yourself of falsehood day by day: will you not abandon these crude fallacies? When you eat where do you put your hand, to your mouth or to your eye? When you bathe into what do you go? When did you ever call the jug a saucer or the ladle a spit?”
He concludes his lecture by advising his audience not to waste their time trying to convince their opponents:
“Such men trifle with us; they take advantage of all the gifts of nature, while in theory they do away with them … It is useless to go on disputing with one of these men, or reasoning with him, or trying to alter his opinion. One might have very much more hope of altering the mind of a profligate than of men who are absolutely deaf and blind to their own miseries.”
Rather, what we should do is to focus on what is really important, to use philosophy for the common good, not to score logical points in useless diatribes.