Aaron Spink

When Descartes made his scientific work public, he ushered in a worldview based almost entirely on mechanical motion, which brought along a complete rejection of “occult” forces. Thus, the foundation of astrology was equally rejected by many prominent Cartesians. However, the popularity of Descartes’ system lead to its rapid adoption by many subjects, astrology included. Here, I will take a look at the curious case of Claude Gadroys, whose primary work, Discours sur les influences des astres, defends a mechanical account of astrology that accords with Descartes’ principles. Gadroys’ Discours employs a sophisticated strategy to rehabilitate astrology of the 17th century against Pico della Mirandola, among other critics. Gadroys’ theory even incorporates Descartes’ discovery, contra the scholastics, that the sublunary and celestial spheres do not differ in kind. Surprisingly, Gadroys uses Descartes’ discovery to substantiate the stars influencing the Earth, whereas earlier astrologers required such a distinction. Gadroys’ adoption of Cartesian philosophy highlights two major theses. First, the advent of mechanical philosophy in no way necessitated the downfall of astrology; instead, it merely changed the direction of astrological explanation for those that followed current science. Second, it shows the selective nature of Cartesian explanation and hypotheses.

ABSTRACTJacques Rohault is often considered to be one of the most meticulous followers of Descartes. Despite this, Rohault’s natural philosophy lacks much of the metaphysical bulwark that typifies Cartesian treatises of the seventeenth century. Instead, Rohault’s work, as well as his popular weekly meetings, strongly emphasized rigorous observation and experimentation. Traditionally, this emphasis on experiment over metaphysics is seen as a pragmatic omission to avoid the perils associated with censorship and Cartesian metaphysics. However, I find that the lack of explicit metaphysics has real consequences that play out in the role Rohault assigns to experimentation. To show this, I highlight several areas where he adopts a broad experimental methodology even though Descartes explicitly rejects the relevancy of experiment on metaphysical topics. I place special emphasis Rohault’s extensive experiment on the void. In short, Rohault’s experimentation was designed to prove, through experimental mea...

The conception of René Descartes as the arch-rationalist has been sufficiently exploded in recent literature; however, there is still a large lacuna in our understanding of how empirical research and experimentation fits within his philosophy. My dissertation is directed at addressing just this problem. I contend that Descartes’ famed method is not a singular monolith but instead two interdependent methods: one directed at metaphysical and epistemological truth, while the other directed at empirical questions and contingent facts of the world. I claim there is evidence for this position not only in his actual scientific practice, but also in the rhetorical structure of the Discourse on Method and the Principles of Philosophy. In exploring the empirical side of Descartes’ method, I show how his unusual system produces a system of experiment designed to serve both as a discovery and verification tool at the same time. As a further application of my interpretation, I argue that the Passions of the Soul and Descartes’ ethical theory expressed in his correspondence must also be seen as part of his two-fold methodology. Instead of attempting to cast Descartes as a virtue ethicist or deontologist, as is normally done, I emphasize that Descartes’ ethics is centered on the mind-body union, and therefore, includes an empirical element as well. The end result is an ethics that requires a detailed study of mechanics, anatomy, physics, as well as medicine. Lastly, I show how this methodology can help us understand the works of some of his early followers: Claude Gadroys and Jacques Rohault. Both of these philosophers not only serve to ground my interpretation, but also to highlight aspects of Cartesian that have often been passed over. I show how the experimentalism of Jacques Rohault goes beyond the epistemological boundaries set up by Descartes, as signifies a new direction that will ultimately eclipse the Cartesian school of thought. In the case of Claude Gadroys, I present a concrete example of the exploitation of the over generality of Cartesian principles. In so doing, I show that while Descartes’ experimentalism was intended to rule out the possibility of occult causes, he in fact created a system that allowed for them, only under a different guise.

In lieu of an abstract, here is a brief excerpt of the content:Reviewed by:Dutch Cartesianism and the Birth of Philosophy of Science by Andrea StrazzoniAaron SpinkAndrea Strazzoni. Dutch Cartesianism and the Birth of Philosophy of Science. Berlin: Walter de Gruyter, 2019. Pp. ix + 245. Hardback, $124.99.Andrea Strazzoni's Dutch Cartesianism and the Birth of Philosophy of Science is a clear step forward in our understanding of the rise and fall of Cartesianism. The work, limited to the Dutch context with one notable German excursion, covers roughly one hundred years starting from the 1630s. While the time frame is rather large in scope, the majority of the work is narrower in focus, with a heavy emphasis on the academic circles in mid-to-late seventeenth-century Leiden and Utrecht. It is thus a welcome addition to the growing body of literature dealing with the unique political, religious, and academic contexts in which Dutch Cartesians found themselves. While much of the book deals with the philosophy of Descartes and then Newton, Strazzoni is not concerned with giving any novel interpretations of either figure; instead, he sheds a great deal of light on a cast of characters who are only now coming to be appreciated for their contributions and influence on philosophical movements of the seventeenth and early eighteenth centuries. The book has two main explicit goals. First, Strazzoni wants to show why foundationalism came to play such a prominent role in Dutch Cartesian circles and what foundationalism's effects were. Second, through this examination, Strazzoni hopes to show that the multiplication of worldviews [End Page 154] shaped a new function for metaphysics and logic as tools for examining principles, which in turn determined a change in the function of philosophy itself that eventually gave birth to a kind of philosophy of science familiar to us today.Strazzoni divides this project into eight chapters, with a focus on six figures: Henricus Regius, Johannes Clauberg, Johannes de Raey, Arnold Geulincx, Burchard de Volder, and Willem Jacob's Gravesande. In addition to a brief overview of the goals and structure of the work, the first chapter includes a survey of how methodologies have changed in the history of philosophy and the history of the philosophy of science, which will be helpful background for those less familiar with the fields.The following two chapters deal with the crises that emerged in Utrecht and Leiden over the spread of Cartesian philosophy. In chapter 2, building on Theo Verbeek's work, Regius takes center stage. While some context of the Utrecht crisis is given, Strazzoni spends much of the chapter detailing how Regius's medical background led to a more empirical approach and lack of metaphysical foundation. While Regius's own controversial positions embroiled both himself and Descartes in the Utrecht Crisis, ripple effects spread to Leiden, resulting in prohibitions against discussions of Cartesian philosophy. In the third chapter, Strazzoni highlights a group of anti-Cartesians, with Jacob Revius as the primary antagonist, and the responses from De Raey and Clauberg. Clauberg, the subject of Strazzoni's only sustained discussion of Cartesianism from Germany, coordinated with de Raey on both a positive campaign of promotion and strategizing responses to the anti-Cartesian front. Outside of discussing Clauberg's explicit role in Leiden, Strazzoni studies his logic and Ontosophia, neatly explaining his shift to more metaphysical foundations.Chapters 4, 5, and 6 continue exploring the various approaches and roles for foundational philosophy in more detail, delving into how these controversies motivated renewed analysis of core Cartesian principles with integration into an academic curriculum in mind. Apart from de Raey's efforts to show that Cartesianism was aligned with Aristotelianism, Strazzoni claims a period of Cartesian physics without an explicit preoccupation with metaphysical questions, especially in light of the restrictions imposed by the curators of Leiden's university. However, as Spinoza and Hobbes came to prominence, multiplying the number of philosophical worldviews, foundational arguments were needed to combat them. Strazzoni highlights how varied these responses could be, as Geulincx's own take on foundations leaned heavily toward ethics rather than epistemology, metaphysics, or logic. However, the discussion of Geulincx is much broader, also including illuminating expositions of Geulincx's theology, epistemology, and metaphysics.Chapter 5 expounds further...

Descartes and his early followers were widely seen to be enemies of superstition and the occult. This was particularly visible in the Cartesian movement’s antagonism to astrology. However, why Descartes and his early followers were so pitted against astrology is less than clear given the flexibility afforded to them through their system of philosophy and various mechanical explanations. Claude Gadroys (1642-1678), for example, produced a short treatise that provided a mechanical explanation consistent with Cartesian physics to allow for celestial influence on Earth. In doing so, he exposed a contradiction in Cartesian vortex theory that seemed to disallow any such influence. In this way, Gadroys brought against himself and then dispelled one of the strongest objections to a Cartesian astrology. Oddly, no other Cartesian relied on principles specific to Cartesianism to argue against astrology as a legitimate science. This paper’s goal is to give a survey of some of the most prominent anti-astrological influences on Descartes, as well as some of the most prominent anti-astrological Cartesians in the second half of the 17th century. In doing this, I hope to show two things. First, in mainstream Cartesianism of the period, the anti-astrological sentiment was in no way part of the debate surrounding Descartes’ philosophy. Instead, ‘Cartesian’ anti-astrological arguments were based on well-worn arguments with an emphasis on experimental difficulties in establishing an astrological science. Second, the explanation for the curious lack of distinctly Cartesian anti-astrological arguments reflects an inherent flaw in Cartesianism; namely, it lacked the theoretical tools to completely rule out ‘occult’ sciences such as astrology.