Last year I wrote a piece on artistic taste, which got many good responses from (eg) Ozy, Frank Lantz, and Sympathetic Opposition. I tastelessly forgot to respond to them until now, but I appreciate how they forced me to refine my thinking. In particular, they helped me realize that "taste" and "good art" are hard to talk about, because the discussions conflate many different things:
1: Sensory Delight. Ode To Joy makes the listener feel joyful. Michelangelo's David fills the viewer with awe at the human figure. The great cathedrals are impressive buildings, in a way that hits you like a punch to the gut. These judgments are preconscious, widespread, and don't necessarily require artistic sophistication.
2: Novelty and Innovation: Someone gets credit for doing art in a way that has never been done before. The early Impressionists invented a new way of looking at the world and explored all of its little corners. A modern Impressionist painter may be able to match their technical skill, but not their novelty; therefore, the modern would be a mere curiosity while the originals were great artists. For a modern person to be a great artist, they would have to explore entirely new media - hence the surprising and transgressive nature of modern art.
3: Paying Attention / Pattern Language: Tasteful people, viewing art over the generations and paying deep attention to it, have developed a sense of balance, composition, contrast, and what should and shouldn't be done. We can debate how predetermined the exact grammar of this language was a priori, but for better or worse people are sensitized to it and will judge works with it in mind. A good work of art should either conform to this language, or defy it deliberately and thoughtfully (that is, in a way that transcends it rather than ignores it).
Along with these three big ones, here are smaller ones that might or might not be combinations or subvarieties of these:
4: Context And Discussion: Some great art raises questions, and subsequent great art proposes answers, or variations on the questions, or further elucidates the subject. The great artists of any given time are in conversation with their peers and the great artists of all past ages; new art can be judged on whether it shows awareness of, and contributes to, this conversation. Other forms of context are more personal - is a book about human evil more aesthetic if its author survived the Holocaust?
5: Literal Ability To Understand A Work: You can't fully appreciate Animal Farm unless you know the history of Soviet communism and recognize the book as an allegory for that history. If someone who knew nothing about this liked it as a cute story about talking animals, their appreciation would be different from (inferior to?) that of more knowledgeable people.
6: Changing Fashions: In 1940, Beaux-Arts and Frank Lloyd Wright were the heights of American architecture. By 1950, nobody who was anybody was doing Beaux-Arts or Prairie; it was all International Style. One could very charitably attribute this to the novelty-seeking drive above; but it's implausible that Prairie style architecture was novel and beloved in 1940, a few houses completely exhausted its potential, but the explosion of International Style buildings didn't restore the balance such that the low-hanging-fruit level level was lower in Prairie style again. More likely this was just a fashion effect where Prairie style was cool in 1940, then uncool in 1950.
7: Political And Ideological Point-Making: Great art may convey some truth about the world. This could be a purely aesthetic truth. But in the case of Uncle Tom's Cabin, the truth was "slavery is bad". Other truths are conveyed symbolically (for example, cathedrals being shaped like crosses) or through design choices (for example, the austerity of Bauhaus architecture making it more suitable for socialist housing).
8: Ability To Profoundly Affect Or Transform You: Maybe this one is emergent from some combination of sensory delight, novelty and point-making. But some people say they come away from art transformed, in a way which is neither just sensory delight nor just political ideology. Philosophers have argued for millennia about exactly what way this is, but hopefully we've all had this experience and can accept an extensional definition.
These people enumerated these things to defend taste. I will instead take the bold stand that conflating many different things is bad: it frees people from thinking too hard about any particular one of them, or the ways they interact. Here are my arguments for deliberately ignoring about half of these.
https://www.astralcodexten.com/p/contra-everyone-on-taste