co-optation of the avant-garde into a commodity produced by neoliberal capitalism makes doubtful that avant-garde artists will remain culturally and intellectually relevant to their societies for preferring profit to cultural change and political progress. In The Theory-Death of the Avant-Garde (1991), Paul Mann said that the avant-garde are economically integral to the contemporary institutions of the Establishment, specifically as part of the culture industry. Noting the conceptual shift, theoreticians, such as Matei Calinescu, in Five Faces of Modernity: Modernism, Avant-garde, Decadence, Kitsch, Postmodernism (1987), and Hans Bertens in The Idea of the Postmodern: A History (1995), said that Western culture entered a post-modern time when the modernist ways of thought and action and the production of art have become redundant in a capitalist economy. Parting from the claims of Greenberg in the late 1930s and the insights of Poggioli in the early 1960s, in The De-Definition of Art: Action Art to Pop to Earthworks (1983), the critic Harold Rosenberg said that since the middle of the 1960s the politically progressive avant-garde ceased being adversaries to artistic commercialism and the mediocrity of mass culture, which political disconnection transformed being an artist into “a profession, one of whose aspects is the pretense of overthrowing [the profession of being an artist].” Moreover, the artistically progressive term avant-garde (advance guard) is compared and contrasted to the artistically reactionary term arrière-garde (rear guard) of artists who oppose the avant-garde as art and as culture The art historians Natalie Adamson and Toby Norris said that the arrière-garde is not reducible to a style of kitsch art or to political reaction, but identifies the cohort of self-conscious artists whose art opposes the legacy of the avant-garde, whilst self-aware that their artistic cohort is anachronistic in the world of the arts; nonetheless, the critic Charles Altieri explans their existence as the interdependence of the genres as art, “where there is an avant-garde, there must be an arrière-garde.” Examples Music Avant-garde in music can refer to any form of music working within traditional structures while seeking to breach boundaries in some manner. The term is used loosely to describe the work of any musicians who radically depart from tradition altogether. By this definition, some avant-garde composers of the 20th century include Arnold Schoenberg, Richard Strauss (in his earliest work), Charles Ives, Igor Stravinsky, Anton Webern, Edgard Varèse, Alban Berg, George Antheil (in his earliest works only), Henry Cowell (in