Abstract

According to Girolamo Fracastoro in his book De contagione, et eorum et contagiosis morbis curatione (1546), contagious diseases are caused by the analogies between the seminaria contagionum (seedlets of contagion) and organisms affected by them. Such analogies are governed by the laws of sympathy and antipathy that regulate the universal order of things, according to the Neo-Platonic philosophy of the Renaissance, whose influence was decisive in the discourse of the physician of the Verona. The purpose of this paper is to investigate the sources and possible reasons that led Fracastoro to support an idea that, due to its apparent qualitative nature, would contradict its rejection to the hidden qualities in explaining the etiology of contagion.