ABSTRACT
There are many notable thought experiments (TEs) in the writings of the two great natural philosophers Isaac Newton (1642–1727) and Gottfried Leibniz (1646–1716). The one most often cited from Newton's work is his thought experiment with the rotating bucket, by which he undermined Descartes's relational account of motion. Leibniz's most famous work, perhaps, is the thought experiment concerning the mill given in his Monadology, which he uses to argue for the non-reducibility of perception to mechanical operations. One can detect a theme underlying these various thought experiments, and some others besides. This is the attempt to use indistinguishability arguments to throw light on the nature of motion and matter. So rather than proceeding case by case, the author situate these thought experiments in a continuous narrative based on that theme. A case in point is the TE Newton gave in De gravitatione, which is very revealing about his views on substance and God's relation to the created world.
