This paper considers Newton’s position on gravity’s cause, both conceptually and historically. With respect to the historical question, I argue that while Newton entertained various hypotheses about gravity’s cause, he never endorsed any of them, and in particular, his lack of confidence in the hypothesis of robust and unmediated distant action by matter is explained by an inclination toward certain metaphysical principles. The conceptual problem about gravity’s cause, which I identified earlier along with a deeper problem about individuating substances, is (...) that a decisive conclusion is impossible unless certain speculative aspects of his empiricism are abandoned. In this paper, I situate those conceptual problems in Newton’s natural philosophy. They arise from ideas that push empiricism to potentially self-defeating limits, revealing the danger of allowing immaterial spirits any place in natural philosophy, especially spatially extended spirits supposed capable of co-occupying place with material bodies. Yet because their source ideas are speculative, Newton’s method ensures that these problems pose no threat to his rational mechanics or the profitable core of his empiricism. They are easily avoided by avoiding their source ideas, and when science emerges from natural philosophy, it does so with an ontology unencumbered by immaterial spirits. (shrink)

Deduction Versus Discourse: Newton and the Cosmic Phenomena Content Type Journal Article Pages 1-16 DOI 10.1007/s10699-011-9283-2 Authors Pierre Kerszberg, University of Toulouse, Toulouse, France Journal Foundations of Science Online ISSN 1572-8471 Print ISSN 1233-1821.

Unlike all preceding theorists of cometary tail formation, Newton introduced a mechanism in which a comet's tail was produced by the convection of rarified ethereal particles which carried with them particles from the comet's upper atmosphere, which in turn became heated by reflecting of the sun's rays. The centrality of the action of the ether particles in this theory made it problematic, as a consistent theory of the ether was not then available. As a result, the theory was not wholly (...) accepted even by some of Newton's closest colleagues and disciples. This paper briefly presents Newton's theory of tail formation and examines its reception, primarily in England. I review seven accounts of cometary tail formation that were developed in a Newtonian framework and published between 1696 and 1757 by William Whiston, David Gregory, Henry Pemberton, Voltaire, Colin Maclaurin, J. T. Desaguliers, and Benjamin Martin. Newton's comet theory showed both philosophical and practical defects typical of his better known work, and I identify four major issues that early Newtonians disputed. These disagreements show that we still have much to learn about the way Newton's physics was studied in the 18th century. (shrink)

In the fourth book of An Essay Concerning Human Understanding Locke hints that he could explain how God may have created matter ex nihilo, but refrains from doing so. Leibniz, when he came upon this passage, pricked up his ears. There ensued a sequence of personal events which are not without charm and piquancy, and a sequence of philosophical events which are of some interest. In this paper we tell the tale.