Full Idea
In Goodman's account, knowing what a painting represents is logically like understanding a sentence in a natural language. It requires a grasp of the 'symbol system' to which the painting belongs.
Gist of Idea
Art is like understanding a natural language, and needs a grasp of a symbol system
Source
report of Nelson Goodman (The Languages of Art [1976]) by Sebastian Gardner - Aesthetics 2.3.2
Book Reference
'Philosophy: a Guide Through the Subject', ed/tr. Grayling,A.C. [OUP 1995], p.603
A Reaction
This may fit some pictures well (e.g. early Flemish painting, with its complex iconography), but others hardly at all. You can enjoy a first experience of (say) ballet long before you get the hang of the 'symbol system' involved.