Yael Kedar

Yael Kedar is a senior lecturer in philosophy at Tel Hai College. She specializes in late medieval philosophy, with a focus on epistemology, scientific method, and philosophy of nature. She has written on light and color – their ontological status and their perception; on physical causality, the concept of laws of nature, the quantification of physics, and on the Medieval scientific method. She serves as the vice president of the Roger Bacon Research Society and the Middle East convenor of the International Robert Grosseteste Society. She edited several special peer-reviewed journal issues on the following topics: laws of nature, quantities, Roger Bacon, and is now engaged in editing a special issue on the medieval concept of infinity. She is a co-chief editor of the Routledge book series Global Perspectives on Natural Philosophy. She won several ISF (Israel Science Foundation) grants and organized two large-scale ISF workshops. She was a research fellow at Georgetown University, Friedrich Alexander University in Erlangen, and at the Thomas Institute at the University of Koln. Her publications include papers in top-notch journals such as Synthese, Journal for the History of Philosophy, and Studies in the History and Philosophy of Science, as well as book chapters and encyclopedia entries. Her current projects deal with Medieval Franciscan science in general and with the thirteenth-century concepts of space and heaviness in particular.

Abstract:  This research project investigates how thirteenth-century Franciscan natural philosophers interpreted and developed Aristotelian concepts of natural place, heaviness, and condensation. While Aristotle's general theory of place has received considerable scholarly attention, the concept of natural place and its causal powers remains understudied, particularly within the Franciscan intellectual tradition. This project examines how Franciscan thinkers attempted to resolve fundamental tensions in Aristotelian physics, especially how natural place exert causal influence on material bodies. Through analysis of works by Robert Grosseteste, Roger Bacon, John Pecham, Richard of Middleton, Geoffrey of Aspall, and the anonymous Summa philosophiae, the study explores how these scholars linked the intrinsic tendency of elements toward their natural places with the extrinsic spatial locations of natural places. The project aims to demonstrate that thirteenth-century Franciscan interpretations of these problems led to innovative theoretical developments, including more quantitative approaches to heaviness and new theories attributing efficient causation to natural place.