Body and void and Newton's \textit{De mundi systemate}: some new sources (Q2538104)

This article is characterfstic of a recent current in Newtonian research. By a close reading of Newton's manuscripts and by comparing them to his published writings, historians are attempting to describe more precisely Newton's philosophical position. It is no mean task, and is not aided by the fact that Newton's extreme caution made him reluctant to reveal his mind, even in his own private papers. The manuscripts published and carefully analyzed in this article are draft revisions of book III of the ``Principia'' that Newton made for the third edition. His several revisions of the ``Principia'' and ``Opticks'' reveal his desire to strengthen the foundations of his philosophy in his later years; and the many draft manuscripts indicate how seriously he undertook the task. The draft revisions for the third edition show clearly the impact of his controversy with Leibniz. The problem of matter and the void comes up again as Newton attempts to defend himself against Leibniz' criticisms. The author asserts that Newton believed in a void (a term that needed careful definition) in spite of his occasional flirtation with the universal ether. The reasons for his belief were primarily metaphysical and theological and not the product of his experimental philosophy. His ideas on atomism came not from Descartes, but from Gassendi, Walter Charleton, and the Cambridge Platonists. Thus from Henry More he learned that space had a greater perfection and permanence than bodies and an absolute reality beyond the mere relations between the parts of matter. After Leibniz' attack on these metaphysical ideas, Newton moved to strengthen his position. But he was caught in his own characteristic ambivalence: on the one hand he tried to avoid the controversy altogether by defining the ``phenomena'' useful to natural philosophy in such a way as to exclude the realm of metaphysics; while on the other hand, he saw, as did Leibniz and Clarke, that in his ``experimental philosophy'' lay the foundations of a metaphysical system -- a system directly opposed to that of Leibniz and one that would have to be defended on metaphysical grounds.