I love Edward Gorey’s theory of art:
“Art…is presumably about some certain thing, but is really always about something else, and it’s no good having one without the other, because if you just have the something it is boring and if you just have the something else it’s irritating.”
Yes, I am currently on a Gorey jag where I go back and reread all the books I have and look for more. It happens periodically.
This time I’m letting myself sink into all the books about him.
There are several! Here’s just the ones I have, aside from the one I’m reading now. And there are at least three more I want. But “Born to Be Posthumous” is a true biography and extremely thorough.
One of those focuses on his art, another is a collection of interviews he’s done, and “Elephant House” is about his house and the weird and wondrous things therein.
There are also books about his plays, a book about the buttons he made for them, a book collecting his correspondence…
That's just some preplatonic philosophy you can catch from Iamblichus: (1) something good in itself, like pleasure, (2) something good for something else, e.g money, power, fame, etc. and (3) something both good in itself and useful for other things - wisdom. It's also in The Republic, I think.
So, applied to art, if a work of art is merely nice to look at then it's boring. If it's got a political message but is not enjoyable then it's irritating. The ideal is both enjoyable and edifying.