Feeling must have a medium in order to function at all; in the same way, thought must have symbols. It is the medium, or the specific configuration of the medium that we call a work of art that brings feeling into being, just as do responses tot the objects of the external world... The medium of painting is such changing and ordering on an ideal plane, ideal in that the medium is more tractable, subtle, and capable of emphasis (abstraction is a kind of emphasis) than everyday life.

pp. 38-39 - Beyond the Aesthetics (1946)