Full Idea
Aesthetics traditionally has two presuppositions: the first is that there is a distinctive form of experience which is common to the appreciation of art and natural beauty; the second is that art has an essence or some sort of underlying unity.
Gist of Idea
Aesthetics presupposes a distinctive sort of experience, and a unified essence for art
Source
Sebastian Gardner (Aesthetics [1995], Intro)
Book Reference
'Philosophy: a Guide Through the Subject', ed/tr. Grayling,A.C. [OUP 1995], p.585
A Reaction
Both must come up for discussion. I think the biggest problem for the first one is the place of sexual attraction, or even fancying a prawn sandwich. The second has been weakened by Marcel Duchamp's urinal, and modern fringe arts.