As a sequel to my previous question, how would you translate ἡ τοῦ ἀγαθοῦ ἰδέα ("the idea of the good") into Latin? I'm referring to the concept in Plato's Republic, where in Book VI he analogizes the idea of the good with the sun, which shines light on everything.
I suppose one efficient approach would be to find a Latin translation of The Republic and locate this passage (Bk VI 538e) in the Latin translation. But I'm actually not aware of any complete Latin translation or whether it's possible to locate this particular section with ease.
Just to share with you some preliminary research, I spent some time on Whitaker's words looking for suitable Latin nouns. I came up with imago, conceptum, and cognitio as candidates for "idea", and the word that comes to mind for ἀγαθοῦ would be "boni".
That left me with the candidates "imago/conceptum/cognitio boni" — but I'm not too confident in any of these! It would be nice in addition to coming up with a good translation to provide some commentary on how these candidates succeed or fall short.