οὐκοῦν interrogative: not therefore? not then? (nonne, igitur? nonne ergo?). Here the stress lies on the inferential οὖν and an affirmative answer is expected as a matter of course. οὐκοῦν stands at the beginning of its clause.
οὐκοῦν . . . εὖ σοι δοκοῦσι βουλεύεσθαι; πρός γε ἃ ὁρῶσι do you not then think that they lay their plans well? Yes, with regard to what they see C. 7.1.8.
a. When a negative answer is expected we have οὐκοῦν οὐ ( Phil. 43d).
b. οὐκοῦν and οὖν stand in parallel questions in A. 1.6.7-8.
c. Some scholars write οὔκουν or οὐκ οὖν for οὐκοῦν interrogative (and inferential).
οὐκοῦν inferential: then, well then, therefore, accordingly (ergo, igitur). Inferential οὐκοῦν was developed, probably in colloquial speech, from the interrogative use, the speaker anticipating the affirmative answer to his question and emphasizing only the inference. From the negative question all that was left was an expression of his own opinion on the part of the speaker. οὐκοῦν has become so completely equivalent to οὖν that a negative has to be added if one is required.
οὐκοῦν, ὅταν δὴ μὴ σθένω, πεπαύσομαι well then, when my strength fails, I shall cease Ant. 91, ἢ . . . τοὺς ἀμῡ́νεσθαι κελεύοντας πόλεμον ποιεῖν φήσομεν; οὐκοῦν ὑπόλοιπον δουλεύειν
or shall we say that those who bid us defend ourselves make war? Then it is left for us to be slaves 8.59. οὐκοῦν is used even with imperatives; as οὐκοῦν . . . ἱκανῶς ἐχέτω
accordingly let it suffice Phae. 274b.
a. Editors often differ whether, in certain cases, οὐκοῦν is interrogative or inferential.
οὔκουν not then, therefore not, so not, at any rate . . . not, surely not (non igitur, non ergo). Here οὐ is strongly emphasized, and οὖν is either confirmative or inferential. οὔκουν is usually placed at the beginning of its clause.
a. In emphatic negative answers; as οὔκουν ἔμοιγε δοκεῖ
certainly not, in my opinion at least O. 1.9.
b. In continuous discourse ( L. 807a).
c. οὔκουν . . . γε returns a negative answer with qualified acquiescence in a preceding statement. Thus, τούτων ἄρα Ζεύς ἐστιν ἀσθενέστερος; οὔκουν ἂν ἐκφύγοι γε τὴν πεπρωμένην
is Zeus then weaker than these? Fate at least he surely cannot escape Pr. 517.
d. In impatient or excited questions (non? non igitur?). Thus, οὔκουν ἐρεῖς ποτ᾽, εἶτ᾽ ἀπαλλαχθεὶς ἄπει; wilt thou not speak and so depart and be gone? Ant. 244.
οὐκ (μὴ) οὖν is to be distinguished from οὐκοῦν or οὔκουν. Thus, ὁπότε καὶ πείρᾳ του σφαλεῖεν, οὐκ οὖν καὶ τὴν πόλιν γε τῆς σφετέρᾱς ἀρετῆς ἀξιοῦντες στερίσκειν
whenever they were foiled in any attempt they did not for this reason think it right to deprive their city of their valour 2.43 (μὴ οὖν 8. 91).
a. Hdt. has οὐκ ὦν (sometimes written οὔκων) to emphasize an idea opposed to what goes before (non tamen). Thus, ταῦτα λέγοντες τοὺς Κροτωνιήτᾱς οὐκ ὦν ἔπειθον by these words they did not however persuade the men of Croton 3. 137.