By the time the Bayreuth Festspielhaus opened its doors in 1876, the metaphor of depth seemed to have found its true calling in the nostalgia and irrationalism of Wagner and his exegetes. For those attuned to Wagnerian metaphysics, references to depth conveyed a series of mutually reinforcing commitments, among them belief in the superior inwardness of Germans and German music, reverence for Germanic mythology, and hostility toward modernity. The young Friedrich Nietzsche, entranced by Wagner and his music, described the ideal experience of the composer’s musical tragedies as a voyage beyond the “surface” of existence into the “interior” realm of unconscious emotion. In the inaugural issue of the Bayreuther Blätter, the editor, Hans von Wolzogen, praised the “deep, unrelenting earnestness and great truthfulness” of Wagner’s music and its potential to liberate the German spirit from the constraints of modern civilization. Wagner’s tireless promoter in England, William Ashton Ellis, preached a similar gospel in his journal The Meister. Ellis likened Wagner and his “deeply-searching spirit” to Kant and Schopenhauer, lauding the composer’s ability to “get down beneath the surface of appearances to the solid rock of its foundation in the universal feelings of mankind.” All of these initiates considered Wagner’s music an unparalleled vehicle of deep emotional and metaphysical revelation.

Wagner and his followers may have done more than anyone in the latter part of the nineteenth century to ensure the continued circulation of musical depth metaphors, but they lacked the power to legislate what it meant for music to be deep. Not everyone was convinced that music’s depth was primarily a matter of the emotions and feelings (let alone the deep metaphysical truths) that Wagnerites such as Wolzogen and Ellis held dear. In his 1854 treatise On the Musically Beautiful, Eduard Hanslick lambasted the feeling-centered aesthetic discourse spawned by Romanticism as contrary to the intellectual spirit of the age, which demanded the pursuit of objectivity in “all areas of knowledge.” Research into the nature of musical beauty, Hanslick contended, should be modeled on the natural sciences. Calling for a more scientific mode of criticism, he proposed that “the primary object of aesthetic inquiry is the beautiful object, not the feeling subject.” The critic’s highest task was to “penetrate the interior of the works and explain, from the laws of their own being, the musical content in which their beauty resides.” Hanslick thereby declared the “deep” responses of listeners off-limits to scholarly investigation; the only depths commonly available for study belonged to musical objects, not listening subjects. Hanslick’s language strongly echoed that of A. B. Marx in his less programmatic moods. Together, their relentless focus on music’s “interior” laid the foundations for modern musical formalism, which, as Lydia Goehr explains, transfers meaning “from music’s outside into its inside.”