A letter written by Christiaan Huygens to David Gregory is published here for the first time. After an introduction about the contacts between the two correspondents, an annotated English translation of the letter is given. The letter forms part of the wider correspondence about the ‘new calculus’, in which L'Hospital and Leibniz also participated, and gives some new evidence about Huygens's ambivalent attitude towards the new developments. Therefore, two mathematical passages in the letter are discussed separately. An appendix contains the (...) original Latin text. (shrink)

Archibald Pitcairne’s medical writings are inspired by Newton’s Principia mathematica, as the Scottish physician assumed Newtonian physics as a model for scientific inquiry that should be applied to other branches of natural philosophy, including physiology and pathology. The ideal of a comprehensive mathematical science was very appealing to late seventeenth-century intellectuals, including physicians. This essay focuses on how Pitcairne tried to implement these ideas. In particular, I argue that Pitcairne’s medical thinking is based on three philosophical assumptions: first, a methodological (...) assumption, for which medical knowledge should be sought in the form of a deductive system; second, an epistemological assumption, that is, that our knowledge of physiological processes is sound only when we reduce them to a set of mathematical laws; and, third, an ontological assumption that identifies blood as the substance on which animal life most directly depends. I also suggest that such ideas should be studied against the backdrop of Pitcairne’s general mindset, including his personal sympathy for political conservativism. I further argue that his insistence on the reduction of natural processes to mathematical relations and his search for the universal order of nature also connect to his religious and political ideals. (shrink)