Xiaona Wang, Handling Occult Qualities

Occult, secret, or hidden causes, qualities, and powers were a mainstay in medieval and early modern explanations of seemingly intractable phenomena, such as magnetism and the power of poisons. Unlike the four manifest or sensible qualities linked to the elements, according to prevailing theories, occult causes stemmed from substantial or specific forms, a concept key to Aristotelian understandings of hylomorphism. Even though some philosophers of the schools employed these occult qualities, they were especially prominent in natural magic;, Galenic toxicology and pharmacology;, astrological accounts of epidemics;, and, after Jean Fernel, etiologies of devastating diseases of the “whole substance.” Xiaona Wang’s impressively researched book, Handling “Occult Qualities” in the Scientific Revolution, demonstrates the myriad concerns and reassessments of occult qualities and causes among mostly seventeenth-century English thinkers, who appropriated and reacted to the natural magic tradition and to Galileo Galilei’s and René Descartes’s rejection of occult qualities.