SVF I.187

Original — Ancient Greek

αὐτάρκη τε εἶναι αὐτὴν (scil. τὴν ἀρετήν) πρὸς εὐδαιμονίαν, καθά φησι Ζήνων.

StoicOs Translation

And it [virtue] is self-sufficient for happiness, as Zeno says.

Context

Diogenes Laërtius, writing around five centuries after Zeno, records this in his survey of Stoic ethics, tagging the thesis explicitly with Zeno's name (καθά φησι Ζήνων). Two independent traditions — Greek doxography and Cicero's Latin — transmit the same claim, which strengthens the attribution.

Source notes:Greek text verified against H. von Arnim, SVF I (1903), no. 187, p. 46 (scanned page); the words (scil. τὴν ἀρετήν) are von Arnim's clarification of the pronoun. Under the same number von Arnim adds a second, Latin witness: Cicero, De finibus 5.79 (“virtus ad beate vivendum se ipsa contenta est”).

What the source actually tells us

This testimony reports the thesis, in Diogenes' wording, that virtue by itself suffices for eudaimonia. The attribution to Zeno is explicit and independently paralleled in Cicero; the six-word formulation, however, is the reporter's, not a quotation from Zeno's books.

Philosophical meaning

This is the boldest claim of Stoic ethics: nothing outside your character — not health, wealth or reputation — is needed for a flourishing life. Virtue is not one ingredient of happiness among others; it is the whole of it. Everything else, the school will say, is preferred or dispreferred, but indifferent to eudaimonia.

Practical wisdom

Zeno's thesis offers a daily test: when you feel your happiness depends on an outcome, ask whether anything has been subtracted from your character. If not, on the Stoic account nothing essential has been lost — and the work returns to the one place it can succeed: how you choose.

Go deeper

• The four Stoic virtues explained →
• Study eudaimonia in Stoic Ethics →