How would you translate ἡ τοῦ ἀγαθοῦ ἰδέα into Latin?

Question

Question

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.

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Preliminary research

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.

Answer 1

A corpus search shows some hits for idea. You can use the Latinized word idea as such, or you can use the Greek word with Greek declension and alphabet. By far the simplest choice is idea, and it refers rather unambiguously to the correct philosophical concept.

One of the hits also suggests a translation. In Tusculanae Disputationes Cicero remarks: ἰδέαν appellat [Plato], nos speciem. If you trust Cicero's authority on this, you can translate the idea to Latin as species.

I think boni is a good choice. Another option worth consideration is bonitatis.

In conclusion, I would suggest idea boni, but also species bonitatis or any mixture thereof sounds acceptable.