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)

In the first paper of this pair, I argued the importance of theories of the imagination in debates on divination [Vermeir, K. . The ‘physical prophet’ and the powers of the imagination. Part I: A case-study on prophecy, vapours and the imagination . Studies in History and Philosophy of Science C, 35, 561–591]. In the present article, I will rely on these results in order to unearth the role of the imagination in a discussion on dowsing. References to the imagination (...) were often implicit because of its negative associations, but I show in detail how the imagination was used to negotiate between the material and the spiritual, and between the natural, the supernatural and the moral. Natural philosophers, theologians and moralists all struggled for authority over divinatory phenomena. The debate evolved around the questions whether moral states could be naturalised and whether subtle material vapours could have moral qualities. (shrink)

This paper investigates the development of Hobbes’s theory of imagination and its unique intervention in the scientific debates of the seventeenth century. I argue that this intervention is designed to solve a tension between Hobbes’s scientific and political commitments. His scientific commitments led him to take the imagination seriously. While unorthodox in many ways, Hobbes was working within the predominant scientific framework of his time, which can be traced back to Aristotle and Galen. The same framework, however, was used for (...) naturalistic explanations for prophecy. This posed a problem for Hobbes, who was equally committed to the advances of science and to guarding against the political threat posed by prophets. I argue that Hobbes’s theory of imagination solves this tension by constructing a scientific account of imagination that is loyal to the leading scientific ideas while ruling out any potential use of imagination in the natural explanation of prophecy. (shrink)