Guiding Part or Governing Part - Stoic Terminology

Piazza and Needleman use the terms "guiding part" and "governing part" to translate the Greek term hēgēmonikon in Marcus Aurelius. Their commentary follows: "The Greek and Roman philosophers viewed the human soul as composed of parts, or aspects, which can be either in harmony or in conflict with each other. Right ordering consists in allowing the naturally rational part to control the lower appetitive parts, with the result being a harmonia of the entire person. Vice and unhappiness result from a kind of inner mutiny, in which the lower appetitive parts rule over the rational, and the latter works in the service of the former."