English translation (word)
English translation (etymon)
Ὡς μὲν Ποσειδώνιος, παρὰ τὸ ἅπτω ἅψω, ἅψις τις οὖσα ἡ φῶς ἐμποιοῦσα καὶ καταυγάζουσα τῶν ὑποκειμένων ἕκαστα, ὡς πῦρ· ὡς δέ τινες, παρὰ τὸ ἅπτω τὸ συνάπτω ἅψις καὶ ὄψις, ἡ διὰ τῶν ὁρατῶν ψαῦσιν ποιουμένη πρὸς κατανόησιν
As Posidonius says, from haptō "to kindle", <future> hapsō, a hapsis "kindling", so to speak, that which produces light and illuminates each of the things it touches, as fire does. But for some, it comes from haptō "to touch", hapsis "touching" and opsis "sight", that which, because it touches the visible things, produces understanding.
The two explanations given here are one and the same etymology, and rely on two different meanings of ἅπτω "to touch" or "to set fire". The formal derivation is the same, the noun ἅψις is derived from the future ἅψω. But the meaning is different, Posidonius argued for the meaning "to kindle", implying that the sight inflames the object and makes it visible, "as fire does"). For others, the basic meaning "to touch" accounts for the fact that sight, conceived as material rays of light produced by the eye, touches the objects and makes them perceptible thereby. This second hypothesis is found elsewhere (see Parallels) whereas Posidonius' idea of fire has no parallel.
Meletius, De natura hominis, p. 69 (διαφέρει δὲ ὄψις ὁράσεως, ὅτι ἡ μὲν ὅρασις, ὅρισίς τις εἶναι δοκεῖ· ἡ τοὺς ὅρους, τουτέστι τὰ πέρατα τῶν σωμάτων καταλαμβάνουσα· ἡ δὲ ὄψις, ἅψις τίς ἐστι, καὶ ψαῦσις τῶν ὁρατῶν κατανόησιν ποιουμένη); Leo Medicus, De natura hominum synopsis 41 (<ἡ> δὲ ὄψις ἅψις τίς ἐστι καὶ ψαῦσις τῶν ὁρατῶν); Ps.-Zonaras, Lexicon, omicron, p. 1494 (Ὄψις. διάκρισις χρωμάτων [καὶ σχημάτων] καὶ ὄγκων. παρὰ τὸ ἅπτω, τὸ συνάπτω, ἅψις καὶ ὄψις. ἡ διὰ τῶν ὁρατῶν ψαῦσιν ποιουμένη πρὸς κατανόησιν. ἢ παρὰ τὸν ὄψω μέλλοντα)