Seminar on History and Philosophy of Science
Abstract: Isaac Newton's Principia (1687) is undoubtedly one of the most well-known books in the history of science. From it, the scholium(commentary) to the definitions is also one of the starting points for some of the richest and longest discussions in the philosophy of physics. Here Newton introduces (in print) the concepts of absolute space and time, and a series of arguments pertaining to distinctions among quantities. Recent scholarship has disentangled the meaning and use of crucial sets of distinctions among motions, such as true vs. apparent, and absolute vs. relative.
Surprisingly, however, scholarship has woefully neglected one topic when it comes to understanding Newton's philosophy in the Scholium. On the one hand, there is the distinction between mathematical and common notions. On the other hand, there is Newton's own emphasis on the use of quantities for the project of the Principia (and of natural philosophy, more broadly). Briefly put, when it comes to the Scholium, there is no math in Newton's philosophy.
I argue in this talk that these two strands of methodology should inform our reading of the Scholium. To this end, I put forward a mathematically informed reading of a well-developed example: the case of the two revolving globes held together by a tensed cord. As I show, the mathematical reading is in the service of broader methodological concerns and is not competing with them. In doing so, I make (unprecedented) use of concepts and models that are at the basis of Newton's entire project. I follow the analysis with several upshots. My reading has important consequences not only for how we understand Newton as a philosopher, but also for discussions in philosophy of physics more broadly.