Mihnea Dobre

Notoriously, Descartes does not have a concept of space. Or more precisely, he takes space as indistinguishable from matter or extension. Yet, to some of his contemporaries, his physics was successful at providing mechanical descriptions of the natural world. In this paper, I discuss the problem of “space” within a larger Cartesian framework, focusing on a case of an experimentally-minded Cartesian who took up the challenge provided by Descartes’s restrictive ontology and tried to accommodate it to experimental trials. One of the most famous debates of seventeenth-century natural philosophy concerns the existence of the vacuum. New instruments were built with the specific purpose of providing clear evidence to support this claim. While a large secondary literature has been devoted to this problem, we still lack a study of the Cartesians involved. Most of the time, Descartes’s followers are taken to merely repeat his words about the contradictory nature of the vacuum, hence their experiments are portrayed as rather misplaced practices. At most, one would find in the literature a discussion about the pedagogical value of these experiments. The consequence is that new experimental approaches provided by Cartesians after Descartes’s death in 1650 are, unfortunately, neglected. By building upon a recent volume, Cartesian Empiricisms, my aim in this paper is to explore the notion of space within Cartesian experimentalism. In doing so, I shall refer to the works of Burchard de Volder, Jacques Rohault, and Samuel Clarke’s annotations of Rohault’s text. Some of the questions I would like to address are as follows: why would a Cartesian natural philosopher perform experiments that are clearly connected to a concept of independent space? What would be the expected outcome? How does the theory (in this case, the Cartesian matter theory) relate to empirical evidence? And how would the latter influence the former? Such questions are relevant for the history of experiment in the early modern period. At the same time, they offer more insights into one of the most intricate problems of Cartesian philosophy, the relation between metaphysics and physics.