We often think of self-mastery as willpower—the stern discipline of saying no to cookies or scrolling. But Plato is pointing at something subtler: the victory over your *illusions* about yourself. A person convinced they're hopelessly lazy, or that they deserve less, or that they can't change—that person is already defeated before any external battle begins. When you stop believing the false stories you've told yourself, you free up the energy for everything else. That accountant who realizes at forty that she despises numbers and actually wants to paint hasn't failed at self-conquest; she's finally won it.