Nicolas Hartsoeker's Système of Nature: Physics by Conjecture and Optics by Design in Early Modern Europe

Abstract

This dissertation sets a detailed, technical history of ideas of Dutch-born lens maker and natural philosopher Nicolas Hartsoeker (1656-1725). Hartsoeker's case exemplifies the kinds of intellectual journeys a university-educated man with technical skills undertook to navigate the chaos and uncertainty of the seventeenth-century world and nature writ large. He defined the labile position of natural philosopher and empiric. His role as practitioner and philosopher reveals the epistemic, disciplinary, and socio-political boundaries he worked within or, in some instances, sought to overcome. He capitalized on his lens-making expertise and tested his often polemical philosophical ideas in printed works and in academic journals of the time. The ways in which he advertised his optical skills, wares, and knowledge about lenses illuminate the extensive possibilities available for self-fashioning and self-advancement in this period for talented lens grinders. Hartsoeker's lens making skills helped him gain access to the Royal Academy of Sciences in Paris (and propelled his lenses all the way to Siam) and the Palatine court in Düsseldorf, where he actively promoted his natural philosophical ideas. This dissertation centers around Hartsoeker's turn away from Descartes' philosophy, and his gradual reassessment of elements of the mechanical philosophy in crafting his own system of nature.

Chapter 1 explores Hartsoeker's early formation in philosophy and medicine in Amsterdam and at the University of Leiden in the 1670s, and sets the stage for his initial passionate support for Descartes' system of the world. In particular, I examine the nature of Dutch Cartesianism through Hartsoeker's university teachers, among whom were Theodoor Craanen, Burchard de Volder, and Johannes de Raey. I show how Hartsoeker's instructors made elements of Cartesian doctrine relevant to solving questions in natural philosophy as well as in medicine, thus inspiring Hartsoeker's early admiration for the French philosopher's ideas. In this chapter, I argue that Descartes' model of matter particles in motion and of the body as machine promised to yield a variety of valid interpretations of natural phenomena.

Chapter 2 examines Hartsoeker's role as instrument maker and his use of materials and tools in launching his own natural philosophical program. I show how his expertise as instrument maker gained him access to the Parisian Academy of Sciences where hypotheses and philosophical ideas made the philosopher. I argue that, for all this empirical know-how, Hartsoeker's philosophical convictions trumped practice and drove his ambition to become a natural philosopher who could make knowledge claims about nature.

Chapter 3 discusses the crucial period in Hartsoeker's intellectual work when he vocally distanced himself from Descartes' philosophy, and endeavored to promote own his system of nature (while at the court of Johann Wilhelm II in Düsseldorf). At its core, this chapter focuses on Hartsoeker's disillusionment with the Cartesian mechanical model of explaining natural phenomena, both in his correspondence with Leibniz and in his writings on anatomy. I argue that Hartsoeker, on the one hand, was wedded to an atomist view of nature; while, on the other hand, he introduced immaterial Intelligences, or intelligent souls, to explain causally vital physiological phenomena that eluded a mechanical interpretation.

Chapter 4 investigates the ways in which Hartsoeker challenged Descartes' mechanical model along the lines of the Cambridge Platonists--Henry More and Ralph Cudworth--in light of Réaumur's experiments on regenerating crayfish legs at the Parisian Academy in 1712. Hartsoeker believed that regeneration of crayfish limbs could not be explained satisfactorily with the Cartesian fundamentals of matter in motion and rejection of animal soul. I argue that the crayfish experiments, as first tried by Réaumur and then repeated by Hartsoeker himself, allowed him to distance himself further from Descartes' philosophy, and develop and assert his proposition that Intelligences mediated between inert matter and God in his system of nature.

Chapter 5 orients Hartsoeker's work and ideas within their immediate and posthumous reception in various French, Dutch and English seventeenth- and early eighteenth-century journals, articles, essays, literary works, and personal correspondence written by his publishers, colleagues, critics, and intellectual heirs. In this chapter, I argue, on the one hand, that contemporaries' engagement with Hartsoeker's ideas sheds light on what they made of his natural philosophical ideas. On the other hand, contemporary reception also helps to characterize the nature and aims of natural philosophy, the procedural aspects of natural philosophical debate, and the kinds of rules that governed the different discussion <italic>fora</italic> that made up the Republic of Letters at this time.