κατὰ ταὐτὰ τοίνυν πρῶτον μὲν τὸ ‘δέον’ οὕτω λεγόμενον τοὐναντίον σημαίνει πᾶσι τοῖς περὶ τὸ ἀγαθὸν ὀνόμασιν: ἀγαθοῦ γὰρ ἰδέα οὖσα τὸ δέον φαίνεται δεσμὸς εἶναι καὶ κώλυμα φορᾶς,
This οὖσα is used instead of ὄν, is this agreement with a predicate substantive normal? Or is this an anacoluthon? Any such instances in Smyth?
and further, 419c κεκλημένῃ ἔοικεν., though LS quotes it as κεκλημένη. In these instances, it seems that the predicate participles agree in gender and case with the predicate substantive not with the subject.
418e is yet another case of attraction. The participle is pulled into the feminine by the directly preceding ιδεα.
It would be different if το δεον preceded. You have to take the word order and the flow of the sentence into account.
yes, thank you, just another instance of this a bit further, 419c ‘χαρὰ’ δὲ τῇ διαχύσει καὶ εὐπορίᾳ τῆς ῥοῆς τῆς ψυχῆς ἔοικε κεκλημένῃ. here Dat instead of Nominative. I wonder if such instances are mentioned in Sm or CGCG.