An exemplum with a hole in the middle. Marcus reminds himself of a scene — and does not give the line: καὶ ἃ εἶπεν ὁ Σωκράτης, "and what Socrates said." The words for whose sake the anecdote is told are left out as known. This is the mark of a notebook: a reference to common property, not a retelling (cf. the neighbouring 11.22–11.25, and the precept of 11.26 to recall some one of the ancients — here it is carried out).
What actually happened. τὸ κῴδιον ὑπεζωσμένος — "girt with a sheepskin": a κῴδιον is an undressed fleece, the garment of a shepherd or a pauper, not of a philosopher. The cause is domestic: Xanthippe went out taking his ἱμάτιον — the outer cloak without which a respectable Athenian did not appear in public. Socrates went out in what there was.
Whose shame it is. The movement of the passage turns on the distribution of shame: αἰδεσθεῖσι καὶ ἀναχωρήσασιν — DOGMAthe friends "were ashamed and withdrew". It is not Socrates who is ashamed but those beside him; and they did not merely blush, they drew off — that is, preferred not to be seen with him. Marcus notes not Socrates's nerve but the reaction of others, because that is what is being tested: one's own composure is easy to imagine, the ability to stay beside a man who looks ridiculous is not.
Why this is not about plain living. The passage does not stand among the calls to frugality (4.30) but among the exercises of memory. Its subject is not a cloak but the price of another's gaze: the man who has gone out in a sheepskin has no stake in the common reckoning of decencies, and is therefore untouchable. Cf. 11.23, where the opinions of the many are called children's bogeys, and 11.25, the second Socratic anecdote of this same run. The governing discipline is assent, the sustaining one action.