Discourses 2.26

Every error involves a contradiction. For since he who is in error does not wish to err, but to be right, it is clear that he is not doing what he wishes. For what does the thief wish to achieve? His own interest. Therefore, if thievery is against his interest, he is not doing what he wishes. Now every rational soul is by nature offended by contradiction; and so, as long as a man does not understand that he is involved in contradiction, there is nothing to prevent him from doing contradictory things, but when he has come to understand the contradiction, he must of necessity abandon and avoid it, just as a bitter necessity compels a man to renounce the false when he perceives that it is false; but as long as the falsehood does not appear, he assents to it as the truth.

He, then, who can show to each man the contradiction which causes him to err, and can clearly bring home to him how he is not doing what he wishes, and is doing what he does not wish, is strong in argument, and at the same time effective both in encouragement and refutation. For as soon as anyone shows a man this, he will of his own accord abandon what he is doing. But so long as you do not point this out, be not surprised if he persists in his error; for he does it because he has an impression that he is right. That is why Socrates, because he trusted in this faculty, used to say: "I am not in the habit of calling any other witness to what I say, but I am always satisfied with my fellow-disputant, and I call for his vote and summon him as a witness, and he, though but a single person, is sufficient for me in place of all men." For Socrates knew what moves a rational soul, and that like the beam of a balance it will incline, whether you wish or no. Point out to the rational governing faculty a contradiction and it will desist; but if you do not point it out, blame yourself rather than the man who will not be persuaded.

Epictetus, Discourses 2.26, translated by W. A. Oldfather

Every error comprehends contradiction: for since he who errs does not wish to err, but to be right, it is plain that he does not do what he wishes. For what does the thief wish to do? That which is for his own interest. If then the theft is not for his interest, he does not do that which he wishes. But every rational soul is by nature offended at contradiction, and so long as it does not understand this contradiction, it is not hindered from doing contradictory things: but when it does understand the contradiction, it must of necessity avoid the contradiction and avoid it as much as a man must dissent from the false when he sees that a thing is false; but so long as this falsehood does not appear to him, he assents to it as to truth.

He then is strong in argument and has the faculty of exhorting and confuting, who is able to show to each man the contradiction through which he errs and clearly to prove how he does not do that which he wishes and does that which he does not wish. For if any one shall show this, a man will himself withdraw from that which he does; but so long as you do not show this, do not be surprised if a man persists in his practice; for having the appearance of doing right, he does what he does. For this reason Socrates also trusting to this power used to say, I am used to call no other witness of what I say, but I am always satisfied with him with whom I am discussing, and I ask him to give his opinion and call him as a witness, and though he is only one, he is sufficient in the place of all. For Socrates knew by what the rational soul is moved, just like a pair of scales, and then it must incline, whether it chooses or not. Show the rational governing faculty a contradiction, and it will withdraw from it; but if you do not show it, rather blame yourself than him who is not persuaded.

Epictetus, Discourses 2.26, translated by George Long

Every error implies conflict; for since he who errs does not wish to go wrong but to go right, plainly he is not doing what he wishes. For what does the thief wish to do? What is to his interest. If then thieving is against his interest, he is not doing what he wishes. But every rational soul by nature dislikes conflict; and so, as long as a man does not understand that he is in conflict, there is nothing to prevent him from doing conflicting acts, but, whenever he understands, strong necessity makes him abandon the conflict and avoid it, just as bitter necessity makes a man renounce a falsehood when he discovers it, though as long as he has not this impression he assents to it as true.

He then who can show to each man the conflict which causes his error, and can clearly bring home to him how he fails to do what he wishes and does what he does not wish, is powerful in argument and strong to encourage and convict. For if one shows this, a man will retire from his error of himself; but as long as you do not succeed in showing this, you need not wonder if he persists in his error, for he acts because he has an impression that he is right. That is why Socrates too, relying on this faculty, said, 'I am not wont to produce any other witness to support what I say, but am content with him to whom I am talking on each occasion; it is his vote that I take, his evidence that I call, and his sole word suffices instead of all.' For Socrates knew what moves the rational soul, and that it will incline to what moves it, whether it wishes to or not. Show the conflict to the rational Governing Principle and it will desist. If you do not show it, blame yourself rather than him who refuses to obey.

Epictetus, Discourses 2.26, translated by P. E. Matheson