Kant’s Cognitive Semantics, Newton’s Rule Four of Philosophy and Scientific Realism

Kant’s Critique of Pure Reason contains an original and powerful semantics of singular cognitive reference which has important implications for epistemology and for philosophy of science. Here I argue that Kant’s semantics directly and strongly supports Newton’s Rule 4 of Philosophy in ways which support Newton’s realism about gravitational force. I begin with Newton’s Rule 4 of Philosophy and its role in Newton’s justification of realism about gravitational force (§2). Next I briefly summarize Kant’s semantics of singular cognitive reference (§3), and then show that it is embedded in and strongly supports Newton’s Rule 4, and that it rules out not only Cartesian physics (per Harper) but also Cartesian, infallibilist presumptions about empirical justification generally (§4). This result exposes a key fallacy in Bas van Fraassen’s original argument for his anti-realist Constructive Empiricism (§5).