It is an old idea that physics became divorced from metaphysics when Newtonians sought to protect themselves from Cartesian and Leibnizian critique. But while the broad idea is plausible, it is imprecise. As recent scholarship has shown, the banner of Newtonianism was taken up by a wide variety of thinkers who forged a wide variety of Newtonianisms, some Cartesian, some Leibnizian, some in the life sciences, some in the moral sciences, etc. (This is the subject of [A7], and some of this scholarship is in [E1]). To the extent that the general thesis is true (which, of course, sweeps under the rug a century of philosophical development leading to Kant), I believe it must be demonstrated with regard to specific beliefs, which are abandoned/retained in response to specific pressures. My work in this area provides a detailed account of Newton’s metaphysical struggles. It shows how his nuanced methodological stances became nuanced in response to external critique, and how his deeply held metaphysical commitments were (sometimes) abandoned, or at least qualified, for the same reasons.
Abandonment is the subject of [A12] and [A6]. These trace Newton’s rejection of certain theses about the metaphysical underpinning of his accounts of space and matter to interactions with Roger Cotes and Leibniz. They also highlight the developmental dimension of his thought and his willingness (though not keenness) to change his opinions or make them more precise. One of their common themes is that Newton did not immediately grasp the full implications of his own Principia, and only came to see (some of) them through confrontation with his contemporaries. The essays, particularly [A6], also highlight Newton’s attempts to make clear his new way of inquiry in the face of more traditional conceptions of natural philosophy and its evidentiary sources. [A18] continues this line of thought by completing the argument of [A12].
My other work on Newton stresses how Newton retained some metaphysical theses, how his views were intertwined with them, and how his natural philosophy could at times be rather conservative. In [A14], I argue that Newton’s Regulae Philosophandi were predicated on deeply held theological beliefs and that they were less methodologically innovative than some recent scholarship suggests. This idea also informs [A8] and [A9]. The latter further suggests that Newton, precisely because he was both innovative and conservative, raises interesting historiographical problems. [A13], and indirectly (20), continue the theme of conservatism by detailing how a pre-1687 Newton tried to make his natural philosophy fit more traditional molds. From a methodological angle, my work on Newton tries to address the issues on which traditional scholars focused, but through the lens of more technically oriented recent scholarship. My next step in this line of research is to examine eighteenth-century accounts that take the relation of metaphysics and physics within varieties of Newtonianism as indicative of the shape of human knowledge as a whole.