Ἀρετὴ αὐτάρκης πρὸς εὐδαιμονίαν — "virtue is sufficient for happiness." One of the hardest and most characteristic Stoic theses: for a happy life (understood as TERMεὔρους βίος — the smooth flow of existence) one needs only virtue, and nothing besides. Health, wealth, reputation, children, country — all these are "indifferents" (ἀδιάφορα); their presence or absence does not alter the status of a life as one that has gone well. The thesis provokes the natural objection ("but the person deprived of health suffers!"), and the Stoic answer: suffering is the artefact of false assents (pathos), not an objective deficit. The sage on the rack is eudaimōn to exactly the same degree as the sage in a palace.

SVF I 187 (Zeno); III 49–67 (Chrysippus' extensive argumentation); the classical formulations: DL VII 127; Stob. Ecl. II 71, 99 W; Cic. De fin. III 27; Tusc. V (the whole — "De virtute ad beate vivendum satis," the principal treatise); Sen. Ep. 9 (on the self-sufficiency of the sage); LS 63. In Marcus the thesis is everywhere assumed, but especially explicit at Med. 1.16; 2.5; 4.32 ("how few things are needed for blessedness"); 7.67; 9.42; 12.27.

In 02-05 the doctrine is given a closing rhetorical formulation: ὁρᾷς πῶς ὀλίγα ἐστίν, ὧν κρατήσας τις δύναται εὔρουν καὶ θεουδῆ βιῶσαι βίον — "see how few things one must master in order to live a smoothly-flowing, god-fearing life." "A few things" = the four virtues (σεμνότης, φιλοστοργία, ἐλευθερία, δικαιότης) + freedom from the passions + the absence of murmuring against fate (amor-fati). This narrow list is the "sufficient" for eudaimonia. Linked to dichotomy-of-control: only virtue is in "what is up to us," and only virtue is what is needed; a happy dependence on the external is therefore ruled out not as a sub-ideal, but as a category error.