διακρίνας σαφέστατά τε καὶ ἀκριβέστατα τὰς τέσσαρας ἀντιθέσεις, καὶ τοὺτων τὴν μὲν καλέσας ὑπεναντίαν, αἵτινες οὐκ ἀεὶ μερίζουσι τὸ ἀληθές καὶ τὸ ψεῦδος ἀλλὰ συναληθέυουσι, τοῦτ’ ἔστιν αἱ μερικαὶ προτάσεις καὶ αἱ ἀπροσδιόριστοι, τὴν δὲ καλέσας ἐναντίαν, φημὶ δὴ τὴν καθόλου πρότασιν τὴν καταφατικὴν καὶ τὴν ἀποφατικὴν, αἵτινες πάλιν ἐπὶ τῆς ένδεχομένης ὕλης συμψεύδονται, τὰς δὲ λοιπάς ἀντιθέσεις τὴν τε τῶν καθ’ ἕκαστα καὶ τὴν μάχην τῆς μερικῆς πρὸς τὴν καθόλου εἴτε καταφατικῆς εἴτε ἀποφατικῆς εἰπὼν ἀντιφατικῶς μάχεσθαι, ταῦτα οὖν πάντα εἰπὼν διὰ τῶν προλαβόντων ζητεῖ νῦν καλῶς ὅτι ἐπὶ μὲν τῶν ἄλλων τριῶν ἀντιθέσεων ἐπὶ μὲν τῶν τριῶν χρόνων ὡσαύτως ἕξουσιν κατὰ τὸ μερίζειν τὸ ἀληθὲς καὶ τὸ ψεῦδος ἢ τὸ συναληθεύειν ἢ τὸ συμψεύδεσθαι.
Having clearly and sufficiently distinguished the four oppositions, he calls some of them subcontraries. Subcontraries are either particular or indefinite propositions that do not always divide truth and falsehood but agree [sometimes] in truth. He calls other propositions ‘opposite.’ Opposite propositions are universal propositions, either affirmative or negative, that agree in falsehood in the matter of possibility. He calls the rest of the oppositions ‘contradictions.’ They include propositions with individual subjects and particular and universal propositions (whether affirmative or negative) that are contradictorily opposed to each other. Having said all this, he now rightly seeks to demonstrate by means of what has been stated before, that in the case of the other three oppositions in the three tenses they will all divide truth and falsehood or agree in truth and falsehood in the same way as the other oppositions.
I dont know how to do it better. In addition, this construction ζητεῖ νῦν καλῶς ὅτι is probably elliptical, and some inf should be understood before ὅτι.