HEAT, COLDNESS, AND CONTRARIETY IN LATE SCHOLASTIC PHILOSOPHY

Abstract

While it is well known that heat played a dominant role in the development of modern science, the fact that its status had already begun to evolve drastically in earlier periods is much less recognized. Although not pertaining exclusively to the Aristotelian framework, by the late Middle Ages, heat was deeply embedded in the Aristotelian worldview, which dominated much of Western natural philosophy. In this framework, heat was classified as a fundamental quality, interacting with other elemental qualities in natural processes. In Aristotle’s system, heat, along with cold, wet, and dry, was part of a theory of contrariety that explained change and transformation in the natural world: this is the aspect of Aristotle’s theory of heat that is privileged in this paper. In the early modern period, unlike concepts such as ‘substantial form’, which were discredited by modern science, heat persisted but underwent a profound ontological shift. No longer a positive entity, it came to be understood as a process, specifically a form of motion, marking a decisive departure from medieval interpretations. This study traces the pre-history of this transition by analyzing how the notion of positive contrariety between heat and cold was progressively dismantled in the late Middle Ages and Renaissance. First, it examines the shift from a binary model of contrariety to a relative scale of thermal properties. Second, it discusses Cardano’s critique of the Aristotelian view of cold as a positive contrary, which stimulated significant debate. Finally, it explores how redefinitions of resistance in the 16^th century further undermined the traditional model, paving the way for mechanistic and empirical approaches that culminated in modern thermodynamics.