What is the dichotomy of control in Stoicism?

The dichotomy of control is the foundational Stoic idea, stated in the opening line of Epictetus’s Enchiridion: some things are up to us and some are not. Up to us are our judgments, choices, desires, and responses. Not up to us are our bodies, reputations, possessions, other people, and outcomes in the world. Nearly all suffering, Epictetus argues, comes from confusing the two — from staking our peace on things we don’t actually govern. The practice is to invest fully in the first category and hold the second loosely: work hard for a result, but locate your wellbeing in the effort and the choice, not the outcome. Modern readers sometimes soften it to a “trichotomy” (things we control, don’t control, and partly influence), but the core move is the same — pour yourself into what is yours to decide, and release what was never yours to command.