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When referring to this work, full bibliographic details including the author, title, awarding institution and date of the thesis must be given. ‘Though their Causes be not yet discover’d’: Occult Principles in the Making of Newton’s Natural Philosophy Xiaona Wang PhD Thesis The University of Edinburgh April 2019 Abstract This thesis aims to provide a fuller understanding of a highly important but still controversial aspect of Isaac Newton’s natural philosophy: the role of occult, or at least non-mechanical, principles in his natural philosophy. The most obvious of these was his belief that gravity was an attractive force which operated across empty space, and so was an occult actio in distans. But there are other aspects of Newton’s work which would have been regarded by Cartesian contemporaries as occult; such as his belief that light can be an active component within bodies, that light and other matter can be converted into one another, and that bodies are not inert and passive but manifest various principles of activity. R. S. Westfall, suggested in the 1970s that Newton’s unprecedented success as a natural philosopher was due to the fact that he combined two seemingly antithetical traditions of natural knowledge, the mechanical tradition, and what he called the Hermetic tradition. This thesis replaces Westfall’s outdated notion of a “Hermetic” tradition with broader occult or natural magical traditions and shows how they formed the context within which Newton’s own work was formed. The thesis is not primarily a study of Newton’s work but a study of the work of earlier English thinkers who can be seen to have established the occult traditions which were subsequently taken up by Newton. Each chapter, therefore, focuses on a different aspect of occult ways of thinking in natural philosophy during the early modern period, and finally shows, in the conclusion to each chapter, how these ideas appeared in Newton’s work, and, as Westfall suggested, contributed to his unprecedented success. Over six chapters the thesis considers theories that the world system is a network of radiating forces analogous to light rays, that gravity is an attractive force analogous to magnetism and operates at a distance, that matter has the power to attract and repel other matter, or has the power to incessantly emit active material effluvia, or the power to vibrate. It also shows how beliefs about the mathematical principles of natural philosophy, and the usefulness of the 2 experimental method made possible, and supported, these theories about occult principles. The focus is on English thinkers and developments in English natural philosophy. This is not just an arbitrary choice but reflects sympathetic attitudes to occult ways of thinking in English thought which are shown to derive from the first natural philosophers in England to acquire international reputations since the Middle Ages, John Dee, Francis Bacon, and William Gilbert. Writing before the mechanical philosophy was conceived, these three thinkers all embraced occult ideas and left them as a legacy for subsequent English thinkers, up to and including Newton. The thesis shows that the combination of occult and mechanical traditions discerned in Newton’s work by Westfall was in fact highly typical of English thinkers who combined occult ideas deriving from Dee, Bacon, and Gilbert, with the emerging mechanical philosophy. This marked trend in English natural philosophy reached its culminating point in the work of Newton, but Newton’s achievement was only possible because of what had gone before. The thesis shows, therefore, that Newton’s achievement crucially depended upon this English background. 3 Lay summary This thesis presents a historical survey of some important aspects of the scientific work which was being produced in England in the seventeenth century, and upon which Isaac Newton (1642–1727) can be shown to have drawn in his own work. Isaac Newton is known to have developed a new physics, in his Principia mathematica (1687) and his Opticks (1704 and 1717) which was not compatible with the dominant scientific theory of his day—the so-called mechanical philosophy, developed by René Descartes (1596–1650) and others. Newton’s theory of gravity (developed in his Principia), for example, seemed to his contemporaries to assume that bodies could act upon one another across empty space, without touching one another, or without any material connection between them. This so-called action-at-a-distance was held to be impossible in the mechanical philosophy. Similarly, in the Opticks he developed the idea that bodies interacted with one another by means of their attractive and repulsive forces—again an idea which was dismissed by mechanical philosophers as non-mechanical and even occult. It is often assumed that these ideas were completely original to Newton, and their appearance in his work is simply attributed to his towering genius. The only attempts by historians to explain his rejection of strictly mechanistic approaches to physics have focused on his work on alchemy—which seems to be an obvious source for his occult ways of thinking. This thesis, however, looks in detail at the development of similar “occult” and non-mechanical ways of thinking by earlier English thinkers; from the earliest English “scientists”: John Dee (1527–1608), William Gilbert (1544–1603), and Francis Bacon (1561–1626), to members of the Royal Society of London, the first scientific society (founded in 1660), including Robert Boyle (1627–1691), Robert Hooke (1635–1703), and others. This thesis shows, therefore, that the occult ways of thinking that can be seen to have shaped Newton’s new physics were already current in English thought (and were by no means confined to 4 alchemy), and already provided a powerful and fruitful alternative to the mechanical philosophy which was dominant in Continental Europe. The power and fruitfulness of these English ideas is shown by the very fact that these ideas can all be seen, as this thesis shows, to have culminated in the highly successful work of Isaac Newton. 5 Acknowledgements First and foremost, I am indebted to my supervisors, Professors John Henry and Thomas Ahnert for all their help and support over the last four years. This thesis could not have been written without the invaluable feedback from their supervision meetings, and from additional regular meetings with Professor Henry. Secondly, my thesis was funded, for the first three years, by the University of Edinburgh/China Scholarships Council Joint Scholarship. I owe further thanks, in the fourth year, for the writing-up predoctoral fellowships awarded to me by The Max Planck Institute for the History of Science, Dept. II, and by the Dr. Günther Findel-Stiftung Predoctoral Fund at the Herzog August Bibliothek. Thanks also to Sergio Orozco Echeverri, who read several early draft chapters and provided highly valuable comments and suggestions. I am also very grateful to the external examiner of my thesis, Professor Rob Iliffe, and the internal examiner, Dr Lawrence Dritsas, who helped to improve my thesis structure, and those scholars who supported or helped with the process of my writing, one way or another: Professors Lorraine Daston, Bernard Lightman, Stephen Bowd, Wu Guosheng, and Silvia Manzo; and also Dr. Dmitri Levitin, Dr. Stephen Clucas, Andrew Lea, Dr. Maria Avxentevskaya, Dr. Elaine Leong, Dr. Sara Miglietti and Dr. Anthony Ossa-Richardson. Last but not least, I’m deeply grateful to my parents, family, and friends, especially to Xiaolu Wang, Jay Han-Li, and Chien-yuen Chen. 6 Declaration I, Xiaona Wang, declare that I composed this thesis, that all the work is my own and that the work has not been submitted for any other degree or professional qualification. Parts of Chapter 3, Sections 4, 5, 6, of this thesis have been previously published in my article “Francis Bacon and Magnetical Cosmology”, Isis 107 (2016): 707–21. _____ ______ _____ 26 April, 2019___________ 7 Table of Contents Abstract ................................................................................................................ 2 Lay summary ....................................................................................................... 4 Acknowledgements .............................................................................................. 6 Declaration ........................................................................................................... 7 Table of Contents ................................................................................................. 8 Introduction ............................................................................................................ 10 Research Aims ..................................................................................................