English translation (word)
English translation (etymon)
ὑπεναντιοῦσθαι δέ φησιν Εὔδημος τοῖς λέγουσιν ἐν τῷ πάσχοντι καὶ κινουμένῳ εἶναι τὴν κίνησιν τὸ περὶ τὰς αἰσθήσεις, λέγομεν γὰρ ὁρᾷ ὁρᾶται ὅρασις, ἀκούει ἀκούεται ἄκουσις. δοκεῖ οὖν ἡ ὅρασις ἐν τῷ ὁρῶντι εἶναι καὶ ἡ ἄκουσις ἐν τῷ ἀκούοντι· ὁμοίως καὶ αἱ γεύσεις καὶ αἱ λοιπαί.
They say Eudemus opposed those who say that for the senses, motion is produced in the passive and moved being. Because we say horāi "he sees", horātai "he is seen", horāsis "seeing", akouei "he hears", akouetai "he is heard", akousis "hearing". So that the seeing is in the seeing one and the hearing in the hearing one. Similarly for taste and so on.
This is the correct explanation, ὅρασις is derived from ὁράω as a regular action noun. The interesting thing is the use Eudemus makes of morphological derivation for a philosophical use: since the action nouns ὅρασις, ἄκουσις are based on the active verbs ὁράω, ἀκούω, not on the passive ones ὅρἀομαι, ἀκούομαι, it implies that they have an active meaning and that the subject of the verb is the source of the perceiving sense (sight or hearing). In order to do that, Eudemus selects the 3sg ὁρᾷ, which is indeed close enough to ὅρᾱσις to be understood as its derivational base (the use of an inflected form as a derivational base was commonplace in Greek etymology).