This came up on another board, but here I can talk to people with some experience in logical analysis, critical thought, debate and argumentation, philosophy and legal thinking:
How do we know music has objective quality, meaning that Britney Spears is not equal to Beethoven?
My pseudo-proof proof:
1. All things have quality; if not physical, quality of organization and truthfulness (correspondence to reality).
2. If Beethoven were played on a kazoo, it would still be good; thus, aesthetic surface qualities are irrelevant (production, voice, etc).
3. We can measure the degree of complexity, complexity of phrase, use of musical elements, etc., and finally derive artistic meaning.
4. Complexity and aesthetics in art are driven by this expression of artistic meaning.
5. Therefore, that which has artistic meaning is going to have quality.
"But that's subjective!"
Answer: everything is subjective based on the limitations of the perceiver. In other words, just because you
can't tell the difference between Britney and Beethoven doesn't mean it does not exist.