This article continues the discussion, begun in an earlier contribution to Perspectives on Science, of recent arguments over the coherence of Newton’s physics. The arguments turn on his use of the term “force” in two apparently different ways in the second law. This ambiguity remains because Newton conceived of mathematics in two entirely different ways—the first as a way of describing how things are in themselves, the second as a method of approximation. These two conceptions were, in turn, reflections of (...) how, according to Newton, one stands in relation to two ideas of God—God as pure being and God as will. (shrink)

For about the last thirty years Newton scholars have carried on a discussion on the meaning of Newton’s second law and its place in the stucture of his physics. E. J. Dijksterhuis, Brian D. Ellis, R. G. A. Dolby, I. Bernard Cohen, and R. S. Westfall in their treatments of these matters all quote a passage that Newton added to the third edition of the Principia. This passage, beginning “Corpore cadente” (“when a body is falling”), was inserted into the Scholium (...) following the Laws. The present article is an analysis of the literature that treats this passage and its relation to the second law. The conclusion is that they are right who see a deep duality in Newton’s mind regarding this law. (shrink)

Newton’s First Law of Motion is typically understood to govern only the motion of force-free bodies. This paper argues on textual and conceptual grounds that it is in fact a stronger, more general principle. The First Law limits the extent to which any body can change its state of motion –– even if that body is subject to impressed forces. The misunderstanding can be traced back to an error in the first English translation of Newton’s Principia, which was published a (...) few years after Newton’s death. (shrink)