"When any person harms you, or speaks badly of you, remember that he acts or speaks from a supposition of its being his duty. Now, it is not possible that he should follow what appears right to you, but what appears so to himself. Therefore, if he judges from a wrong appearance, he is the person hurt, since he too is the person deceived. For if anyone should suppose a true proposition to be false, the proposition is not hurt, but he who is deceived about it. Setting out, then, from these principles, you will meekly bear a person who reviles you, for you will say upon every occasion, "It seemed so to him."

• Epictetus, The Enchiridion

"But the rational and the irrational appear such in a different way to different persons, just as the good and the bad, the profitable and the unprofitable. For this reason, particularly, we need discipline, in order to learn how to adapt the preconception of the rational and the irrational to the several things conformably to nature. But in order to determine the rational and the irrational, we use not only the of external things, but we consider also what is appropriate to each person. For to one man it is consistent with reason to hold a chamber pot for another, and to look to this only, that if he does not hold it, he will receive stripes, and he will not receive his food: but if he shall hold the pot, he will not suffer anything hard or disagreeable. But to another man not only does the holding of a chamber pot appear intolerable for himself, but intolerable also for him to allow another to do this office for him. If, then, you ask me whether you should hold the chamber pot or not, I shall say to you that the receiving of food is worth more than the not receiving of it, and the being scourged is a greater indignity than not being scourged; so that if you measure your interests by these things, go and hold the chamber pot. "But this," you say, "would not be worthy of me." Well, then, it is you who must introduce this consideration into the inquiry, not I; for it is you who know yourself, how much you are worth to yourself, and at what price you sell yourself; for men sell themselves at various prices."

• Epictetus, The Discourses