No one is deprived of truth willingly. Marcus quotes (without the name: φησίν, "he says") a thesis going back to PERSONPlato (~ Sophist 228c; grounded in the Socratic "no one errs willingly"): "every soul is deprived (στέρεται) of truth against its will (ἄκουσα)." The words are not verbatim Plato; in exactly this form they are quoted twice by Epictetus, who credits Plato (Discourses 1.28.4; 2.22.36), and Marcus probably took them from him. Marcus repeats the line at 11.18.

Extension to all the virtues. Marcus's move is to generalize the quote: as of truth, so of TERMjustice, TERMtemperance, and benevolence (εὐμένεια) the soul is deprived involuntarily. If the mind errs only through ignorance, then in ethical failures too no one is a "villain by choice" — all stumble without willing it. Hence the therapeutic conclusion for whose sake the quote is taken: "it is most necessary (ἀναγκαιότατον) to keep this constantly in mind, for you will be gentler (πρᾳότερος) toward all." This is the doctrinal ground of the gentleness of 7.22 and 7.26: anger at the vicious is as absurd as anger at the blind — both are deprived against their will. The governing discipline is action (gentleness toward people); the sustaining one, assent (the diagnosis of involuntariness).