The term ‘realism’ and its contrasting terms have various related senses, although often they occlude as much as they illuminate, especially if ontological and epistemological issues and their tenable combinations are insufficiently clarified. For example, in 1807 the infamous ‘idealist’ Hegel argued cogently that any tenable philosophical theory of knowledge must take the natural and social sciences into very close consideration, which he himself did. Here I argue that Hegel ably and insightfully defends Newton’s causal realism about gravitational force, in (...) part by exposing a fatal equivocation in the traditional concept of substance, by criticizing some still-standard empiricist misconceptions of force, by emphasizing the role of explanatory integration in Newtonian mechanics, and by using his powerful semantics of singular, specifically cognitive reference to justify fallibilism regarding empirical justification, together with the semantic core of Newton’s Rule Four of (experimental) Philosophy—in a way that highlights a key fallacy in many arguments against realism, both in epistemology and within philosophy of science. (shrink)