Mihnea Dobre

Descartes is famous for his metaphysical foundation of his philosophical system. The image of the philosophical tree that he presents in the preface-letter to the French edition of the Principles of Philosophy (1647) offers a straightforward depiction of an organic growth of the philosophical system out of the metaphysical roots. This Cartesian metaphor was copiously exploited by the first Cartesians, who often attempted to represent Descartes's whole system as developing from metaphysical roots. However, the relations between metaphysics, physics, and the rest of the philosophical disciplines were deeply problematic. The book explores the difficulties of the alleged underpinning of Descartes’s physics into the metaphysics. It starts from Descartes’s own works, but expands into an investigation of the early reception of Cartesian physics in the French context. It gives an account of several first-generation Cartesians (Jacques du Roure, Géraud de Cordemoy, François Bayle, and Jacques Rohault), especially of how such figures discussed the passage from metaphysics to physics. The book offers a detailed discussion of the relevant writings of these authors, especially of those publications concerned with the foundation of natural philosophy and with its relation to metaphysics. The study of early forms of French Cartesianism is done also to refer back to Descartes, such that the solutions provided by his early followers are called to provide a better understanding of the philosophical problems identified in the writings of their more famous contemporary.

This chapter explores the intellectual development of Jacques Rohault – although not considered one of the leading figures of the early modern period, well known among historians of science. It attempts to evaluate Rohault’s Cartesianism and to present it in a more nuanced manner than it is usually illustrated in the literature. Focusing on his mature work, published only one year before his death in 1672, but also referring to his earlier activities in Paris and to the publication of his posthumous works, the chapter argues that his “Cartesianism” came rather late in his thinking, while his early activity concerns mathematics and mechanics. The reading endorsed in this chapter opens a fresh perspective on Rohault’s experimentalism, suggesting a transition from practical mathematics to Cartesian natural philosophy.

This article addresses the problem of Jacques Rohault’s Cartesianism. It aims to enrich the current portrayal of Rohault (1618–72) as a Cartesian natural philosopher concerned with experimentation. The modern evaluation of Rohault as an experimentalist can benefit from another explanatory layer, emphasizing the mathematical physics that shapes his natural philosophy. In order to argue for this complementary account, I focus on an early episode in Rohault’s career, represented by his reply to Fermat’s attacks against Descartes’s law of refraction (1658). The source has been discussed, so far, solely as part of the dispute in optics between Fermat and the Cartesians. The reading endorsed here explores the source from a different angle, suggesting an alternative account grounded on a more contextual understanding of Rohault’s contribution to Cartesianism. More diverse dimensions of Rohault’s intellectual formation are revealed, which in turn provides a more complex picture of this strain of Cartesian natural philosophy.

One of the most difficult, yet interesting change in theseventeenth-century natural philosophy was that of chemistry. This essayfocuses upon Cartesian re-evaluation of the philosophical disciplines,arguing that, from a systematic perspective, chemistry cannot find a place innatural philosophy. Chemistry, in its seventeenth-century form of“chymistry” shares a number of common features with other traditions andpractices. Descartes and his first-generation of followers discussed in thisessay – Jacques du Roure, Robert Desgabets, and Jacques Rohault – willreact precisely to this discipline of “chymistry,” opposing it to their physicsbuilt on a combination between theory of matter and mechanicalexplanations. The very restrictive Cartesian theory of matter will come intotension with any intermediate explanatory entity, such as the chymicalprinciples. This essay will investigate such tensions, arguing that they arecaused by both ontological and epistemological commitments. For example,the principles of the chymists contradict the one material extension of theCartesian world. At the same time, Cartesians require a more thoroughreductive process then the one provided by chymical explanations. In thissense, chymistry is good for practical purposes, but fails in providing anexplanation in natural philosophy and, hence, to represent a science.

The appearance of scientific journals in the second half of the seventeenth century not only presented new opportunities for the dissemination of knowledge, but also offers the historian a privileged view of the shared knowledge within the scientific community. The Journal des Sçavans, founded in 1665, proclaimed its ambition to disseminate news about books and people concerning the République des lettres. Given the reportedly high interest in and opposition to the rise of Cartesianism among contemporary philosophers, this paper explores the discussion of Cartesianism within the pages of the Journal. It is shown that debates on Cartesianism formed only a small portion of the articles in the Journal. Although the majority of commentaries referred to the metaphysical foundations of Cartesian philosophy, a considerable number of instances were found referring to empirical tests of the theory. Finally, as the Journal does not mention the condemnations or censorship of Cartesianism, we cannot speak of a general feeling of hostility against Cartesian philosophers among the editors or intended audience of the Journal.

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.