This is from Epictetus’ Dissertationes ad Arriano Digestae (“Treatises Collected and Edited by Arrian”)
Book 1.5 Against the Academics
“Epictetus said that if someone resists what is clearly true, then it is not easy to devise an argument to persuade him to change his mind. This is due neither to the man’s strength or the teacher’s weakness, but instead because once someone has been assailed and hardens to stone, how could anyone prevail upon him with reason?
Men are hardened to reason in two ways: one is the petrification of thought; the other comes from shame, whenever someone is deployed in battle to such a degree that he will not acknowledge what is obvious or depart from his fellow combatants. Most of us fear the necrosis of our bodies and we will do anything to avoid having this happen in anyway; but we don’t think at all about the mortification of our mind. By Zeus, if a man is disposed in such a way concerning the mind itself that he can’t follow any argument or understand anything, we believe that he is ill. But if shame or self-regard hardens a man, we still persist in calling this strength!
Do you sense that you are awake? “No”, he answers, “Not more than when I imagine that I am awake while I dream.” The fantasy of dreaming differs in no way from being awake? “Not at all.”
How do I have a conversation with this man? What kind of fire or iron can I take to him to make him perceive that he has turned to stone? Although he realizes it, he pretends he does not. He is even worse than a corpse. One man does not perceive the conflict—he is sick. The other perceives it and neither moves nor responds—he is even worse. His sense of shame and his self-regard have been amputated and his reason has not been excised but instead has been mutilated.
Should I call this strength? May it not be so, unless I should also it strength when perverts do and say everything that occurs to them in public.”
ε′. Πρὸς τοὺς ᾿Ακαδημαικούς.
῎Αν τις, φησίν, ἐνίστηται πρὸς τὰ ἄγαν ἐκφανῆ, πρὸς τοῦτον οὐ ῥᾴδιόν ἐστιν εὑ<ρεῖν λόγ>ον, δι’ οὗ μεταπείσει τις αὐτόν. τοῦτο δ’ οὔτε παρὰ <τὴν ἐκεί>νου γίνεται δύναμιν οὔτε παρὰ τὴν τοῦ διδάσκοντος ἀσθένειαν, ἀλλ’ ὅταν ἀπαχθεὶς ἀπολιθωθῇ, πῶς ἔτι χρήσηταί τις αὐτῷ διὰ λόγου;
᾿Απολιθώσεις δ’ εἰσὶ διτταί· ἡ μὲν τοῦ νοητικοῦ ἀπολίθωσις, ἡ δὲ τοῦ ἐντρεπτικοῦ, ὅταν τις παρατεταγμένος ᾖ μὴ ἐπινεύειν τοῖς ἐναργέσι μηδ’ ἀπὸ τῶν μαχομένων ἀφίστασθαι. οἱ δὲ πολλοὶ τὴν μὲν σωματικὴν ἀπονέκρωσιν φοβούμεθα καὶ πάντ’ <ἂν> μηχανησαίμεθα ὑπὲρ τοῦ μὴ περιπεσεῖν τοιούτῳ τινί, τῆς ψυχῆς δ’ ἀπονεκρουμένης οὐδὲν ἡμῖν μέλει. καὶ νὴ Δία ἐπὶ αὐτῆς τῆς ψυχῆς ἂν μὲν ᾖ οὕτως διακείμενος, ὥστε μηδεν<ὶ> παρακολουθεῖν μηδὲ συνιέναι μηδέν, καὶ τοῦτον κακῶς ἔχειν οἰόμεθα· ἂν δέ τινος τὸ ἐντρεπτικὸν καὶ αἰδῆμον ἀπονεκρωθῇ, τοῦτο ἔτι καὶ δύναμιν καλοῦμεν.
Καταλαμβάνεις ὅτι ἐγρήγορας; ‘οὔ’, φησίν· ‘οὐδὲ γάρ, ὅταν ἐν τοῖς ὕπνοις φαντάζωμαι, ὅτι ἐγρήγορα’. οὐδὲν οὖν διαφέρει αὕτη ἡ φαντασία ἐκείνης; ‘οὐδέν’. ἔτι τούτῳ διαλέγομαι; καὶ ποῖον αὐτῷ πῦρ ἢ ποῖον σίδηρον προσαγάγω, ἵν’ αἴσθηται ὅτι νενέκρωται; αἰσθανόμενος οὐ προσποιεῖται· ἔτι χείρων ἐστὶ τοῦ νεκροῦ. μάχην οὗτος οὐ συνορᾷ· κακῶς ἔχει. συνορῶν οὗτος οὐ κινεῖται οὐδὲ προκόπτει· ἔτι ἀθλιώτερον ἔχει. ἐκτέτμηται τὸ αἰδῆμον αὐτοῦ καὶ ἐντρεπτικὸν καὶ τὸ λογικὸν οὐκ ἀποτέτμηται, ἀλλ’ ἀποτεθηρίωται. ταύτην ἐγὼ δύναμιν εἴπω; μὴ γένοιτο, εἰ μὴ καὶ τὴν τῶν κιναίδων, καθ’ ἣν πᾶν τὸ ἐπελθὸν ἐν μέσῳ καὶ ποιοῦσι καὶ λέγουσι.