The most consistent radical figure of postwar music was John Cage, the father of chance music. (Charles Ives has to count as the grandfather.) He studied with Schoenberg, among others — when Schoenberg was teaching in California, Cage’s home state — and early developed an almost bewildering variety of interests. Cage exhibited specially prepared prints, toured as music director of avant-garde dancer Merce Cunningham’s dance company, and was a recognized mycologist (mushroom authority). In the 1950s, his study of Zen Buddhism led him to a fresh attitude toward music, time, and indeed all experience.

Cage posed questions that challenge all the assumptions on which traditional music rests. Why should music be different from the sounds of life? Why compose with “musical” sounds, rather than noises? Why work out music according to melodies, climaxes, twelve-tone series, or anything else that gives the impression of one thing following another in a purposeful order? Why not leave it to chance? The basic message that Cage conveyed is that we should open our ears to every possible kind of sound and every possible sound conjunction. In this, too, he was following in the footsteps of Ives.