Ignorance — not knowing what is TERMgood and what is TERMevil. For the Stoics, ἄγνοια is the root cause of vice: every error in conduct is an error of judgment about the value of things. A bad person is bad not by ill will, but because he falsely takes as a good what is not one (the external things) and as an evil what is not an evil (suffering, dishonour). This is the Socratic inheritance, reworked by the Stoics into the doctrine of the passions (πάθη) as "false judgments."

SVF III 256, 262 (Chrysippus on πάθη as κρίσεις, "judgments"); DL VII 93; Cic. Tusc. IV 11–14. The Socratic background: Plat. Prot. 357d–358d; Meno 77b–78b. In Marcus: Med. 2.1; 4.3; 05-18 (the wrongdoer errs either in ignorance (ἀγνοῶν) or for show); 06-21; 06-22; 07-22 (they err δι’ ἄγνοιαν and against their will — hence to be loved); 07-66 (Socrates no slave to anyone's ἀγνοία); 11.18.

The famous formula of passage 02-01: "all this has happened to them through ignorance of good and evil" (παρὰ τὴν ἄγνοιαν τῶν ἀγαθῶν καὶ κακῶν). The therapeutic move follows from this diagnosis — not anger but compassion: the one who does harm harms himself first, because he is ignorant of the true scale of values. Compare Med. 7.22: "it is proper to a human being to love even those who err."