SVF I.230

Original — Ancient Greek

ἔτι δὲ καθῆκόν φασιν εἶναι ὃ πραχθὲν εὔλογόν [τε] ἴσχει ἀπολογισμόν· οἷον τὸ ἀκόλουθον ἐν τῇ ζωῇ, ὅπερ καὶ ἐπὶ τὰ φυτὰ καὶ ζῷα διατείνει· ὁρᾶσθαι γὰρ κἀπὶ τούτων καθήκοντα. κατωνομάσθαι δὲ οὕτως ὑπὸ πρώτου Ζήνωνος τὸ καθῆκον, ἀπὸ τοῦ κατά τινας ἥκειν τῆς προσονομασίας εἰλημμένης.

StoicOs Translation

Further, they say that an appropriate action (kathēkon) is that which, when done, admits of a reasonable justification — such as what is consistent in life, something that extends even to plants and animals, for appropriate actions can be observed in these too. And the kathēkon was so named for the first time by Zeno, the designation being taken from its “coming down upon” certain people (kata tinas hēkein).

Context

Diogenes Laërtius, compiling around five centuries after Zeno, summarises the Stoic doctrine of appropriate actions and inserts a precise historical note: the term itself was Zeno's coinage. The book catalogue he preserves elsewhere (DL 7.4) indeed lists a treatise by Zeno entitled On the Appropriate — the ancestor of Cicero's De officiis and of the entire Western literature of duty.

Source notes:Text verified against H. von Arnim, SVF I (1903), no. 230, p. 55 (scanned page). Von Arnim brackets [τε] for deletion, compares DL 7.25 (“they say he was also the first to use the name kathēkon and to write a treatise on it”; the book catalogue, fr. 41, lists a work On the appropriate), and adds the parallels Stobaeus, Ecl. II 7,8 p. 85,13 W. and Cicero, De finibus 3.58.

What the source actually tells us

A testimonium in the doxographer's words. It secures two things: the school definition of the kathēkon (an action that admits of a reasonable justification, consistent with one's life and nature), and — marked as historical fact — that Zeno coined the term, together with an ancient etymology. Whether the definition as quoted is Zeno's own formulation or the school's polished version cannot be decided from this witness.

Philosophical meaning

With one coined word Zeno founded the ethics of everyday life. Between perfect virtue (reserved for the sage) and vice lies the vast field of appropriate actions: caring for health, parents, city — acts that fit a rational nature and can be justified when questioned. Via Cicero's translation officium, Zeno's kathēkon became “duty”, one of the most consequential concepts in Western moral thought.

Scholarly uncertainty

The definition is given for the Stoics collectively (“they say”), so its exact wording may be later than Zeno; only the coining of the term is attributed to him personally. The ancient etymology (kata tinas hēkein) is a doxographer's explanation and linguistically playful rather than certain. One transmitted particle is deleted by the editors.

Practical wisdom

Zeno's test is usable every evening: could I give a reasonable account of what I did today, if asked? Not a perfect account — perfection belongs to the sage — but a reasonable one, consistent with my nature and roles. Duty begins not in grand gestures but in actions you could defend out loud.

Go deeper

• Read SVF I.179 — the end is to live in agreement →
• Study appropriate action in Stoic Ethics →