At the heart of his philosophical and literary work is Diderot’s perpetual exploration of the voice. This article examines how the materialistic writer, caught in an internal tension between annoyance and attraction for sound, attempts to rehabilitate the human voice as sign of vitality. We also emphasise that if the philosophe, whose characters experience the sensitivity of matter, sometimes shows the energy and excess of a vibrating voice, he also expresses the force of passionate human nature which finally loses the idea of its perfectibility but escapes from the prison constructed by the religious and political universe.