εἰ γὰρ μάτην τεθείκασιν οἱ ὀνοματοθέται τὰ ὀνόματα, ἀλλ’ οὖν πάντως κατά τινα λόγον καὶ ἁρμονίαν. I think here the apodosis is missing: for if the name-givers imposed the names in vain , (or a like phrase should be supplied), but on the contrary, they imposed them according to a certain law and harmony.
would it not be simpler to render it as: the name-givers have not imposed the names without reason but…
I don’t believe Hylander is correct. It’s not an unattainable wish, but has simply omitted the obvious protasis. It should be read:
“For if [that’s the case], the name-givers imposed the names in vain, but…”
I see that the LSJ has this usage in εἰ.B.VII.3d, if you want a reference. But it obviously can’t be read as a wish.
Maybe if the op had provided the full passage or a cite.
Yes, I only knew what was going on from the last thread. I believe that Constantinus has limited computer resources (he can correct me), but the source seems to be Stephanus’ commentary on Aristotle. 18.3 in Commentaria in Aristotelem graeca, on page 10. Here it is in Hathi:
https://babel.hathitrust.org/cgi/pt?id=chi.39823940&view=1up&seq=28&skin=2021

Certainly the γαρ functions independently of the ει, as it often does, but there’s no ellipse, and neither the protasis nor the apodosis is omitted. The argument is that if the names/nouns have been assigned ματην, without particular significance, at any rate they’ve been given in accordance with a certain λογος and ἁρμονια. The construction is the same as at Pl. Phaedo 91b (Soc. speaking), εἰ δὲ μηδέν ἐστι τελευτήσαντι, ἀλλ᾽οὖν τοῦτόν γε τὸν χρόνον αὐτὸν τὸν πρὸ τοῦ θανάτου ἧττον τοῖς παροῦσιν ἀηδὴς ἔσομαι ὀδυρόμενος.
That makes a lot of sense. I had taken the μάτην to contradict the second part, but I guess it just communicates “not φύσει” (either α or β), ἀλλ’ οὖν “but at any rate” in every way τοῦ θέσει α (harmonious) and not τοῦ θέσει β “simple”.