"Η θεωρία των ιδεών."

Translation: The theory of ideas.

[Yoel.]

If it's referring to Plato, we call it the theory of Forms.

[JamesTWils]

It's definitely the modern version of the Ancient Greek word Plato uses for the Forms, but it apparently would translate our word "idea" as well. I agree with you, though. If I saw this out of context, I would definitely say the Theory of Forms.

[JamesTWils]

So, if you have an ancient name, like Πλατων, do you decline it like an Ancient Greek noun or like Modern Greek?

[troll1995]

Here You can use either, ancient greek-like declination is more sophisticated, but used.

[Marionsche4]

He also came to my mind straight ahead! Great to meat ppl with some education.

[Jon345104]

Is this a Greek expression if so what does it mean

[Lorentso]

https://en.wikipedia.org/wiki/Theory_of_forms

[MercedesEm13]

the ideas theory.Please tell me why this is wrong.Thanks.