Ever wonder about the origins of Cognitive-Behavioral Therapy? First of all, Albert Ellis was first on the scene -- not Aaron Beck, as is commonly believed. Secondly, Ellis plainly stated (as was his wont) that he lifted the ideas for his Rational-Emotive Behavioral Therapy from the Stoic philosophers Epictetus and Marcus Aurelius.
The entire Enchiridion of Epictetus is available online here.
5. Men are disturbed, not by things, but by the principles and notions which they form concerning things.
8. Don't demand that things happen as you wish, but wish that they happen as they do happen, and you will go on well.
12. If you want to improve, reject such reasonings as these: "If I neglect my affairs, I'll have no income; if I don't correct my servant, he will be bad." For it is better to die with hunger, exempt from grief and fear, than to live in affluence with perturbation; and it is better your servant should be bad, than you unhappy.
Begin therefore from little things. Is a little oil spilt? A little wine stolen? Say to yourself, "This is the price paid for apathy, for tranquillity, and nothing is to be had for nothing." When you call your servant, it is possible that he may not come; or, if he does, he may not do what you want. But he is by no means of such importance that it should be in his power to give you any disturbance.
17. Remember that you are an actor in a drama, of such a kind as the author pleases to make it. If short, of a short one; if long, of a long one. If it is his pleasure you should act a poor man, a cripple, a governor, or a private person, see that you act it naturally. For this is your business, to act well the character assigned you; to choose it is another's.
21. Let death and exile, and all other things which appear terrible be daily before your eyes, but chiefly death, and you win never entertain any abject thought, nor too eagerly covet anything.
33. Immediately prescribe some character and form of conduce to yourself, which you may keep both alone and in company.
Be for the most part silent, or speak merely what is necessary, and in few words. We may, however, enter, though sparingly, into discourse sometimes when occasion calls for it, but not on any of the common subjects, of gladiators, or horse races, or athletic champions, or feasts, the vulgar topics of conversation; but principally not of men, so as either to blame, or praise, or make comparisons. If you are able, then, by your own conversation bring over that of your company to proper subjects; but, if you happen to be taken among strangers, be silent.
Don't allow your laughter be much, nor on many occasions, nor profuse.
Avoid swearing, if possible, altogether; if not, as far as you are able. [General U.S. Grant!]
Avoid public and vulgar entertainments; but, if ever an occasion calls you to them, keep your attention upon the stretch, that you may not imperceptibly slide into vulgar manners. For be assured that if a person be ever so sound himself, yet, if his companion be infected, he who converses with him will be infected likewise.
Provide things relating to the body no further than mere use; as meat, drink, clothing, house, family. But strike off and reject everything relating to show and delicacy.
As far as possible, before marriage, keep yourself pure from familiarities with women, and, if you indulge them, let it be lawfully. But don't therefore be troublesome and full of reproofs to those who use these liberties, nor frequently boast that you yourself don't.
If anyone tells you that such a person speaks ill of you, don't make excuses about what is said of you, but answer: "He does not know my other faults, else he would not have mentioned only these."
45. Does anyone bathe in a mighty little time? Don't say that he does it ill, but in a mighty little time. Does anyone drink a great quantity of wine? Don't say that he does ill, but that he drinks a great quantity. For, unless you perfectly understand the principle from which anyone acts, how should you know if he acts ill? Thus you will not run the hazard of assenting to any appearances but such as you fully comprehend. [B.F. Skinner!]
50. Whatever moral rules you have deliberately proposed to yourself. abide by them as they were laws, and as if you would be guilty of impiety by violating any of them. Don't regard what anyone says of you, for this, after all, is no concern of yours. How long, then, will you put off thinking yourself worthy of the highest improvements and follow the distinctions of reason? You have received the philosophical theorems, with which you ought to be familiar, and you have been familiar with them. What other master, then, do you wait for, to throw upon that the delay of reforming yourself? You are no longer a boy, but a grown man. If, therefore, you will be negligent and slothful, and always add procrastination to procrastination, purpose to purpose, and fix day after day in which you will attend to yourself, you will insensibly continue without proficiency, and, living and dying, persevere in being one of the vulgar. This instant, then, think yourself worthy of living as a man grown up, and a proficient. Let whatever appears to be the best be to you an inviolable law. And if any instance of pain or pleasure, or glory or disgrace, is set before you, remember that now is the combat, now the Olympiad comes on, nor can it be put off. By once being defeated and giving way, proficiency is lost, or by the contrary preserved. Thus Socrates became perfect, improving himself by everything, attending to nothing but reason. And though you are not yet a Socrates, you ought, however, to live as one desirous of becoming a Socrates.
Adm. Jim Stockdale credited Epictetus for helping him to survive captivity in North Vietnam