The European avant-garde movements can be defined as an attack on the status of art in bourgeois society. What is negated is not an earlier form of art but art as an institution that is unassociated with the life praxis of men. When the avant-gardistes demand that art become practical once again, they do not mean that the contents of works of art should be socially significant. The demand is not raised at the level of the contents of individual works. Rather, it directs itself to the way art functions in society, a process that does as much to determine the effect that works have as does the particular content.
Peter Bürger, “Theory of the Avant-Garde”, in Theory and History of Literature, Volume 4, University of Minnesota Press, p49