The dichotomy of control is the idea that everything you meet falls into one of two boxes. In the first are the things that are up to you: your judgments, your choices, where you put your attention, how you respond, your character. In the second is everything else: outcomes, other people's behavior, your reputation, the past, your body, the weather, fate. Almost all unrest, the Stoics held, comes from confusing the two.
The distinction opens the Enchiridion, the short handbook of Epictetus compiled by his student Arrian around the year 125. Epictetus was born a slave, was lamed, and was banished from Rome, and he taught that a person who sorts correctly is free in any circumstance. In Greek the two categories are ta eph'hemin and ta ouk eph'hemin: what is up to us and what is not.
Anyone can say afterwards which box a thing belonged in. The difficulty is seeing it in the heat of the moment, when a judgment has already fired before you had any say. That first movement, the flush, the sting, the surge, is not yours either; the Stoics called them first movements and did not blame anyone for them. The practice begins at the second movement: whether you consent to the judgment or let it die down.
Three traps. First, that the teaching asks for indifference: it does not, since precisely because outcomes are not yours, your effort is all that counts. Second, that acceptance replaces action: acceptance concerns what has already happened, action what comes next. Third, that a practitioner stops feeling: he does not, he only stops being governed by the feeling.
Three steps, over and over. Intercept the judgment before you go along with it. Sort the situation into what is yours and what is not, often splitting a single event into both. Then act carefully on your part and let the rest go. This site is built entirely around that movement: propositions to judge, situations to sort, and cases from history where somebody had to do it for real.
Yours, Not Yours · A Stoic practice ground · All cases