Place in the book. A one-line formula of self-examination: the discipline of assent in its diagnostic mode. Marcus gives not an argument but a question to be put to oneself continually.

"For what am I now using my soul?" πρὸς τί χρῶμαι τῇ TERMψυχῇ — the question to be asked "at every juncture" (παρ’ ἕκαστα), and to "examine" (ἐξετάζειν) what is now in that part "which they call the TERMruling part." Not a final self-audit but an instantaneous cross-section: what is my ruling part like at this very moment.

"Whose soul do I have?" A diagnostic catalogue of degradations: a child's (immaturity), a youth's (heat), a "silly woman's" (γυναικάριον — a derogatory diminutive: weakness), a tyrant's (arbitrariness), a beast's (κτῆνος — dull servitude to need), a wild beast's (θηρίον — ferocity). The soul is defined by its present use: if the ruling part is now moved by fear, lust, or rage, that is an "alien," unfitting soul.

The exercise. This is EXERCISEself-tracking in pure form: not to describe oneself but to catch the quality of the ruling part in the moment (cf. 02-08: not to track the movements of one's own soul necessarily makes one unhappy).

Discipline and parallels. The principal discipline is assent (monitoring the state of the ἡγεμονικόν). Parallel: Med. 2.8 (02-08).