Prohairesis
προαίρεσιςpro-HY-reh-sis
The faculty of moral choice and rational decision-making that defines human agency. For the Stoics, particularly Epictetus, prohairesis represents the ruling center of the self—the one thing entirely within your control and immune to external circumstances.
Modern Application
Your prohairesis is your leadership superpower: the ability to choose your response to any situation, regardless of external pressures. When markets crash, teams fracture, or critics attack, you retain sovereign authority over your judgments and decisions. Train this faculty daily by distinguishing what depends on you from what does not, then directing all your energy toward the former.