Philosophy, Medicine, and Humanism in Cesalpino’s Investigation into Demons

In Daemonum investigatio peripatetica, Andreas Cesalpino argued for the reality of demons and explained their existence and actions using principles of natural philosophy developed in the Quaestiones peripateticae. He stressed the concept of spirit and the presence of divine substance in humans. His discussion of demons attempts to reconcile Hippocratic texts with Aristotle’s views about the “demonic” character of nature, as expressed in On Divination during Sleep. In doing so, Cesalpino distinguished the supernatural, preternatural, and the natural. He contended that demons were immaterial beings that used the factive intelligence to possess and vex their victims. In doing so they act in an analogous way to artisans. Therefore, demonic acts are artificial rather than natural and thus beyond the ordinary course of nature. Since their deeds involve the human soul and spirits, demonic works also are tied to the divine intelligence that pervades nature.