"The chief characteristic of fashion is to impose and suddenly to accept as a new rule or norm what was, until a minute before, an exception or whim, then to abandon it again after it had become a commonplace, everybody's 'thing.' Fashion's task, in brief, is to maintain a continual process of standarization: putting a rarity or novelty into general and universal use, then passing on to another rarity or novelty when the first has ceased to be such. In the sphere of art, we may express this phenomenon by saying that fashion tends to translate a new or strange form into acceptable and imitable dorms and then tu submit some other form to analogous metamorphoses and conversion as soon as the first has been made diffuse and common enough to have turned into what the French call poncif (stencil) and what we might anglicize as ‘stereotype’.
According to Baudelairse's clever paradox, the chief task of genius is precisely to invent a stereotype. We do not have to be reminded that genius is an exquisitely romantic concept, but the modernity of the stereotype is worth emphasizing. The tacitly enunciated task of classic art was the splendid repetition of the eternal maxims of ancient wisdom; impossible, then, for it to conceive the commonplace pejoratively. But since the triumph of the romantic cult of originality and novelty, the aesthetic equivalent of the commonplace has come to be more and more pejoratively considered. That is exactly why the stereotype is a wholly modern concept; by virtue of that modernity there exists, despite any contrary appearances, a connection between the avant-garde and stereotypes. Clement Greenberg in fact tried to establish the existence of such a connection in a Partisan Review article many years ago. He juxtaposed the concepts of avant-garde and of kitsch (the German synonim for the French poncif - if poncif or stereotype signifies the vulgarity of a theme, kitsch underlines the mediocrity or banality of a particular work of art). Greenberg established the connection on a level which was not purely critical o literary. As a leftist critic he maintained that avant-garde and kitsch were the cultural fruits, one as bad as the other, of a unique social, economic, and political situation; aquivalent and parallel results, in the field of art, of the same stage of evolution or, better, the same phase of decadence in bourgeois and capitalistic society. We might sum up Greenberg's position [...] by saying that the coinciding of avant-garde and kitsch shows that we are dealing with a Civilization now unable to produce a Kultur."
R. Poggioli (1962 ) The Theory of the Avant-Garde. pp 79-80
Cambridge, Harvard University Press.