Descartes notoriously characterizes substance in two ways: first, as an ultimate subject of properties ; second, as an independent entity. The characterizations have appeared to many to diverge on the definition as well as the scope of the notion of substance. For it is often thought that the ultimate subject of properties need not—and, in some cases, cannot—be independent. Drawing on a suite of historical, textual, and philosophical considerations, this essay argues for an interpretation that reconciles Descartes's two characterizations. It (...) proposes that both characterizations invoke a type of independence that obtains just in case there is no relation to another entity that holds by the nature of the entity in question. Even though the ultimate subject of properties is sometimes not independent in other respects, it satisfies this independence-by-nature condition. (shrink)

In 1675, Burchard de Volder (1643–1709) was the first professor to introduce the demonstration of experiment into a university physics course and built the Leiden Physics Theatre to accommodate this new pedagogy. When he requested the funds from the university to build the facility, he claimed that the performance of experiments would demonstrate the “truth and certainty” of the postulates of theoretical physics. Such a claim is interesting given de Volder’s lifelong commitment to Cartesian scientia. This chapter will examine de (...) Volder’s views on experiment and show that they are not Newtonian or inductivist, as is sometimes claimed. While de Volder thinks we need deductive reasoning from first principles to provide evidence of the certainty of the content of our physical theories, he also contends that we need experiment to provide evidence of the certainty of the existence of the particular bodies those theories discuss. This approach to experiment is based on a distinction between rational certainty and the certainty of material bodies in the actual world. While this account is deeply influenced by Descartes, it is importantly different than Descartes’ distinction between absolute and moral certainty. De Volder’s “Cartesian Empiricism” is best understood as a continuation and further development of a long tradition of teaching through observation at Leiden. (shrink)

The aim of this dissertation is to provide a critique of the idea that skepticism was the driving force in the development of early modern thought. Historian of philosophy Richard Popkin introduced this thesis in the 1950s and elaborated on it over the next five decades, and recent scholarship shows that it has become an increasingly accepted interpretation. I begin with a study of the relevant historical antecedents—the ancient skeptical traditions of which early modern thinkers were aware—Pyrrhonism and Academicism. Then (...) I discuss the influence of skepticism on three pre-Cartesians: Francisco Sanches, Michel de Montaigne, and Pierre Charron. Basing my arguments on an informed understanding of both ancient Greek skepticism and some of the writings of these philosophers, I contend that it is inaccurate to predominantly characterize Sanches, Montaigne, and Charron as skeptics. To support his thesis about the singular influence of skepticism on early modern thought, Popkin says that René Descartes’ metaphysical philosophy was formed as a response to a skeptical threat and that Descartes ultimately conceded to the force of skepticism. He also argues that David Hume was a Pyrrhonist par excellence. I disagree with Popkin’s claims. I argue that Descartes was not as deeply affected by skepticism as Popkin suggests and that it is inaccurate to characterize Hume as a Pyrrhonist. By offering this critique, I hope to make clear to the readers two things: first, that Popkin’s thesis, though it is both enticing and generally accepted by many scholars, is questionable with regard to its plausibility; second, that the arguments I present in this dissertation reveal that further research into the role of skepticism in early modern philosophy is in order. (shrink)