This dissertation explores work on sound and music by the German physiologist, Hermann von Helmholtz (1821-1894), with a view toward theorizing the modernity of aural practices characteristic of this work. In writings and lectures for popular audiences, Helmholtz used his increasingly public scientific persona to promote the modernization of national education and the liberalization of academic, industrial, and commercial culture. Although not often overtly political, the function of his public speech was carefully coordinated with various reformist projects that became especially pronounced around 1860. His musical work in this period exemplified the potential such modernization offered to re-imagine the human—in all its physiological and psychological density—as a productive assemblage. In experimental practices typical of the "organic physics" of his generation and subculture, the listening person was configured as the site of sensation-producing energy conversions. Yet this listener was more than the receptor and translator of physical movement. Helmholtzian aurality tenuously balanced the mechanical and habitual functions of perception with the reformist impulse to submit listening to a rigorous and virtuoso discipline of attentiveness to the radical particularity of sensation.

Attention—figured at once as a naturalized perceptual disposition, a moral imperative, and a mode of critique with regard to the utilitarian rationality of everyday hearing—became a central problem: it was deemed both necessary in order to maintain sovereignty over perceptual experience, but also impossible to sustain against the uncontrollable circulation of forces in which the subject was immersed. This paradox carried over into Helmholtz's sweeping music historiography. On the one hand, his model of historical progress was driven by a theoretical principle of tonal "affinity," whose semi-mechanical influence on harmonic practice aimed at a unitary vision of musical rationality. On the other hand, hoping to maintain a robust ideal of aesthetic freedom and to preserve some form of cultural choice, Helmholtz guarded a complex conceptual space for musical agency. If this paradox went unresolved in the historiographical context, a no less provisional liberatory potential emerged in the vocal practices and pedagogies Helmholtz valorized as instancing salutary cultural reform through the attentive re-training of the senses and the body.