I could ask you to answer 'the big questions', to tell us what life means or what the teleological truth about our creators or why we seem to all broadly agree on quality of artwork but can't seem to write down the rules of agreement. But you only have those answers for yourself. Further, if the answers which make sense to you can fit on a single page, they likely don't make sense to anybody else.
While you're not a solopsist, you haven't really advanced the state of the discussion.
You mentioned elsewhere that you haven't been asked any hard questions. So, here's the question: Does this 'quality' of art exist in the things which we observe? Or is it subjective, existing only in the observer?
Please think hard on this. Take as much time as you need. When you're ready, first write down your answer in as much detail as you like, to your own confidence. Then, pop open Pirsig's Zen and the Art, starting on p228, and read his thoughts and see what you think.
What exactly do you mean by quality of art? Beauty is just an emotion / feeling triggered when exposed to certain stimuli. It's to some extent encoded in our DNA. Anthropology / human biology / sociology problem.
I could ask you to answer 'the big questions', to tell us what life means or what the teleological truth about our creators or why we seem to all broadly agree on quality of artwork but can't seem to write down the rules of agreement. But you only have those answers for yourself. Further, if the answers which make sense to you can fit on a single page, they likely don't make sense to anybody else.
While you're not a solopsist, you haven't really advanced the state of the discussion.