. . . shock and awe . . . art and outrage . . . provocation and controversey . . . . . . The artists' desire to startle and outrage audiences - especially those belonging to the ruling bourgeois class - was often politically motivated by a desire to contribute to social change by either reform or revolution . . .
'In the historical avante-garde movements, shocking the recipient becomes the dominant principle of artistic intent . . . refusal to provide meaning is experienced as shock . . . And this is the intention of the avant-garde artist, who hopes that such withdrawal of meaning will direct the reader's attention to the fact that the conduct of one's life is questionable and that it is necessary to change it. Shock is aimed for as a stimulus . . . to break through aesthetic immanence and to usher in [initiate] a change in the recipient's life praxis'
That this principle eventually became a convention was confirmed by a statement made in 1989:
That a work of art might outrage some members of society is a normal part of its conditions of existence.
(John A. Walker. Art & Outrage)