"I don't know what art is, but I know what I like." It is so very culturally dependent. I find that I like, quite a lot, African music, which follows entirely different rules from Western. I can appreciate Indian. I do not much like Japanese or Chinese music, though the graphic arts are wonderful --with far different rules. The composition of a photograph is such a right-brain activity, I'm not sure I verbalize it while making the image. Only after the fact can I analyze, and maybe say, "Oh, ya, I used this leading line to emplasize the subject." This does NOT say that composition rules are not important. I advise any photographer to live in art museums and surrounded by books. Then make your own rules.