The rich philosophical and mathematical disputes that took place between Isaac Newton and Gottfried Leibniz at the start of the eighteenth century have received more historical attention than any other exchange in the history of philosophy. Nevertheless, in this talk, Robert Iliffe discusses a prominent but neglected aspect of their disagreement, namely the mutual claim that their opponents’ conceptual foundations were fictional, and were the product both of diseased thinking and of illegitimately organized intellectual structures. Newton assailed Leibniz’s allegedly debased metaphysics in various prominent places, and mobilized allies such as Roger Cotes and John Keill to do the same. Nevertheless, by far the most sophisticated critique of illicit philosophical assumptions was launched against Newton by Leibniz in his correspondence with Samuel Clarke. In the Fifth letter to Clarke, Leibniz identified core Newtonian positions as infantile, vulgar, and profoundly irreligious, asserting that they were dangerous fictions that were less plausible and much less edifying than the rational romances of writers in the previous century. Although Leibniz saved his most potent intellectual weapons for his final letter to Clarke, Robert Iliffe suggests that his attack on the fictional status of Newton’s work was no mere codicil to his general critique of Newton’s philosophy, but instead lay at the heart of it. This famous debate, while of course somewhat sui generis, is indicative of more general and dynamic features of intellectual debate.
Robert Iliffe, Professor of the History of Science at the University of Oxford
This event is part of the New York History of Science Lecture Series.