Cage's musical vocabulary was also influenced by the historical avant-garde. His percussion works (and similar compositions for the same medium by such composers as William Russell, Edgard Varèse, Lou Harrison, and Henry Cowell) gave noise a new musical vitality that went far beyond the dadaist and futurist experiments. Even more important was Cage's interest in breaking down the barriers between art and life, a position often attributed to his studies of Zen Buddhism which also shows unmistakeable parallels with the historical avant-garde. Cage exemplified this aesthetic philosophy with 4'33", perhaps his most crucial contribution to the mid-century revival of avant-garde aesthetics. The description of 4'33"--the musical analog for Robert Rauschenberg's white canvases--as a composition without sound is misleading. 4'33" was not merely a philosophical statement without any real musical content. Cage has maintained that an audience experiencing 4'33" has an opportunity to listen, in an aesthetic way, to what there is to hear.[27] He believed that we are all free at any time and in any place to listen, in a musical way, to the sounds that are around us. He eliminated the distinction between musical and environmental sound, thus achieving a fusion of art and life in a musical context.

These interests drew Cage to many of the techniques developed by the dadaist movement such as simultaneity and chance methods. At Black Mountain College in 1952, Cage staged a now famous performance consisting of several unrelated activities including Merce Cunningham's dancing, David Tudor's piano playing, poetry recitals by Charles Olsen and M. C. Richards, Robert Rauchenberg playing an old fashioned record player, and Cage's own reading from a text by the fourteenth-century mystic and philosopher Meister Eckhardt. This work looked back to the dadaist and futurist performances and also anticipated both the "happenings" that became popular during the 1960s and the "events" staged by the Fluxus movement.[28] Cage's fascination with complex simultaneities of this sort extended throughout his entire career, from his early experiments with electronic media such as Williams Mix, to the enormous superimposition of electronic and other musical media in HPSCHD, to later works such as Cage's Europeras (which although they were perhaps not intended in the same antagonistic spirit, resemble Marinetti's plan for a performance at his "Variety Theater" cited above).

Progress and innovation are necessary claims for an authentic avant-garde. But was an avant-garde possible "après Cage"? The challenge of subsequent generations of avant-garde composers was to discover new modes of musical innovation after Cage had demonstrated that virtually any combination of sounds has musical value. This task was taken on beginning in the 1960s by a group of artists and musicians, many of whom were associated with the Fluxus movement.

During the late 1950s, Cage taught a course in experimental music at the New School for Social Research. His students, among whom were George Brecht, Dick Higgins, Toshi Ichiyanagi, Allan Kaprow, Jackson Mac Low, and Richard Maxfield, went on to become leaders within avant-garde artistic circles including the Fluxus movement. The first official Fluxus concert was held in Wiesbaden in 1962, and was followed by several other concerts throughout Europe featuring works by John Cage, George Brecht, Dick Higgins, La Monte Young, Philip Corner, Nam June Paik, Allison Knowles, Emmet Williams, and many others. These events were organized by George Maciunas, a Lithuanian émigré who was active in the New York avant-grade and largely responsible for the founding of the Fluxus movement. Maciunas outlined the political and social program for Fluxus in a manifesto that he distributed to the audience at the Fluxfest concert in Dusseldorf in February, 1963. Many of the objectives in the manifesto looked back to the historical avant-garde. Fluxus rejected institutional art, was decidedly anti-academic, and against commercialized culture. Art was for the masses and was a means toward social and political change. Maciunas modeled Fluxus after the 1920s Soviet artist collective Left Front for the Arts (Levyi Front Iskusstv) or LEF.[29] LEF endorsed a form of social realism that sought the de-aestheticization and de-institutionalization of art. Artists, according to the precepts endorsed by LEF, had a social responsibility to enhance the everyday lives of the masses. They believed that this could be accomplished through the adornment of utilitarian objects and the mass production of art sponsored by the state.

As did the dadaists before them, the proponents of Fluxus believed in the unity of art and life. In his lecture entitled "Neo-Dada in Music, Theater, Poetry, Art"[30] Maciunas differentiated between "illusionist" art which is artificial and abstract and "concrete art" which draws from processes and materials in the real world. In illusionist art, form and content are separate since the sounds that are produced are not readily equated with their manner of production. The concrete artist prefers noise to so-called musical sounds because the latter are artificial and do not occur as natural phenomena. It is more natural to strike a piano with a hammer than it is to play a Beethoven piano sonata. In the case of the hammer and piano, form and content are equivalent because the sound produced is more easily identified with the materials producing the sound. Maciunas demonstrated concrete sounds with a performance of Nam June Paik's One for Violin Solo (1962) during which a violin is destroyed before the audience. Another noteworthy example is La Monte Young's Poem for Tables, Benches, and Chairs (1960), which consists of sounds produced by a large group of performers dragging furniture across a stage.

These works look back to the dadaist and futurist experiments with noise and most certainly point to Cage's influence. Like Cage, Fluxus composers rejoiced in the musical potential of unconventional sounds. They also often strove to inject a humorous component in their works. Fluxus events and compositions were meant to be unpretentious "art-amusement" based on a "fusion of "Spike Jones, vaudeville, gags, children's games, and Marcel Duchamp."[31] Artists were not to have a professional status in society and their works were meant to be accessible to everyone. There is even a story, told by Dick Higgins, of a janitor who worked at a museum where several Fluxus concerts were staged who brought his children to every concert.[32]

The dadaist claim that art and life should not be separated led Fluxus artists to a new genre of performance art. As early as in 1959 George Brecht and Dick Higgins had been experimenting with compositions consisting of a limited activity described by a brief set of written instructions.[33] In 1960, La Monte Young composed a series of works entitled Compositions 1960 that are sometimes called "short forms" or "word pieces." These pieces, which were later called "events," consisted of an action that was initiated by a concise instruction given to a performer. For example, Composition 1960 No. 2 tells the performer to build a fire in front of the audience. In Composition 1960 No. 5 the performer lets a butterfly loose in the concert hall. Composition 1960 No. 10 instructs the reader to draw a straight line and follow it. Because they usually involve only a single simple action, events should be distinguished from "happenings" which more often involved several simultaneous layers of activity. The reductionism characteristic of "events" is historically significant because it looked forward to the minimalist movement that gained momentum several years later.