Around the turn of the twentieth century, the work of Claude Debussy spurred a reimagining of music and musical listening in which Parisian musicians and intellectuals, informed by recent scientific discourse on affect, perception, and cognition, attempted to articulate a music aesthetics appropriate to the fully embodied, material self of psychological modernism. Important themes in debussyste music criticism are prefigured in the Symbolist wagnérisme of the late 1880s, which elaborated a model of affect and cognition drawn from the empirical psychology of Théodule Ribot. Following the premiere of Debussy’s opera Pelléas et Mélisande in 1902, Debussy’s supporters, attempting to explain the opera’s novelty, turned away from a music aesthetics that gave primacy to inner emotion and toward an aesthetics oriented instead toward listening, sensation, and the materiality of sound. Over the following decade, critics Jean Marnold and Louis Laloy, drawing from a wide swath of early-twentieth-century intellectual culture that included empirical psychology and post-Helmholtzian acoustics, were particularly influential as defenders of the ostensibly scientifically valid nature of Debussy’s innovations as well as his historical importance. After 1910, however, the cultural relevance of debussysme quickly declined as standards of aesthetic value shifted toward the abstract and universal (as opposed to the fleeting ephemerality of sensation) and as the deepening divide between scientific methods and humanistic ones made the intellectual culture of debussysme untenable.