Contagious Vibrations: Sympathetic Resonance as a Model for Disease Transmission in the Writings of Ficino, Fracastoro, and Cardano.

Contagious diseases were among the most vexing problems in ancient theories of health, which could not easily account for how a corruption of one person's humors could cause a similar corruption in another's. One useful explanatory concept for Renaissance doctors tackling this theoretical gap was the phenomenon of resonance or "sympathetic vibration" - where one stationary string begins to vibrate spontaneously when a similarly tuned string is plucked nearby - as both resonance and contagion involved some mysterious, insensible action at a distance between an agent and a patient. Tracing the writings of Marsilio Ficino, Girolamo Fracastoro, and Girolamo Cardano, this essay explores the relationships between the writers' accounts of sympathetic vibrations and their contagion theories. It argues that different conceptions of the acoustic phenomenon - either as a manifestation of a Neo-Platonic World-Soul that underpinned the universe or else as a physical effect - revealed the writers' cosmological views that, in turn, informed their accounts of the human body and disease.