In one of his most influential lectures on indeterminacy, “Composition as Process,” John Cage compared musical composition to a camera, implying that performance can be thought of as an act of making photos. The idea of composition-as-camera suggests a certain understanding of the materiality of sound. Cage's theory of composition and indeterminate performance responded to the emergence of a new epistemology of information and conveyed a probabilistic agenda: a way of apprehending reality that only became possible after the first computers were up and running.