The sage — or, more broadly, the one who has understood where the genuine good lies — cannot be harmed from outside. Since the only real TERMevil is vice, and vice is one's own assent to a bad judgment, no external force can make a person vicious against his will. The external can wound the body, take away property, deprive one of the people one loves — but it cannot touch the TERMruling part unless the ruling part itself yields. The Stoic sage is therefore "unharmable" (ἀβλαβής) — not because he is shielded, but because harm is localised only where he is his own master.

SVF III 567–579 (on the invulnerability of the sage); classically: Plat. Apol. 30c–d, 41d ("the bad person cannot harm the better"); Sen. De const. sap. (a whole treatise on this thesis); Epict. Ench. 5; Disc. 1.18; 3.22.100. In Marcus: Med. 2.1; 2.11; 4.8; 4.49; 05-22 (what does no harm to the city does no harm to the citizen); 05-35; 06-21 (the truth harms no one; harm is persisting in one's own error); 07-14 (the external falls on the sentient parts; the ruling "I" takes no harm unless it judges what happened an evil — and not to judge is in its power); 07-16 (the ruling part suffers no harm unless it harms itself); 07-22 (the wrongdoer has not made your ἡγεμονικόν worse — hence no harm); 07-53 (acting according to one's constitution — no harm to suspect); 07-64 (pain is nothing shameful and makes the governing mind no worse); 8.41; 08-55 (κακία harms not another — only its own bearer, who is free to be rid of it); 08-56 (a neighbour's vice cannot become my evil — God arranged that my unhappiness may not depend on another); 09-04 (the reverse theorem: what harms a person is only what makes him worse — his own injustice; the unjust harms himself); 09-38 (if he erred, the evil is "there," with him; and perhaps he did not err); 09-42 (τί δὲ καὶ βέβλαψαι; no one of those at whom you boil has made your διάνοια worse).

In 02-01 the doctrine is carried through by a direct step: "no one can drag me into the shameful (αἰσχρόν)" — and therefore no one can harm me. The hidden premise: harm = vice = the shameful; everything else is no harm at all. Linked to dichotomy-of-control: harm is possible only in the sphere of what is up to us, and what is up to us is only our own assent. Therapeutically the doctrine removes the ground of anger: if my neighbour is unable to harm me, then indignation against him too is a category error, not a legitimate reaction.