In his late writings, Jean-Philippe Rameau attributed mystical, almost divine qualities to the corps sonore, a fundamental element in his theory of harmonic generation. This article traces the use that Rameau made of the corps sonore in his stage works as part of a tradition of the oracular pronouncements in the French opera. In addition to using it to symbolize enlightenment, starting from the late 1740s Rameau used it to accompany the spells of the benevolent magicians who take the place of the deities of Classical mythology. The fact that the librettist of these works, Louis de Cahusac, was closely associated with Freemasonry substantiates a case for the influence of progressive philosophy over Rameau. This impacted not only the thematics of his stage works, but the symbolic use of the corps sonore in his musical philosophy and the political message conveyed through his operas.