 To see why Hume cannot “approve”, going beyond external properties of bodies, let us take a brief detour through some core elements of Hume’s epistemology. For Hume, we build up our causal theories from experience of particular events (see, for instance, the demands at THN 1.3.14.6–15 and also the footnote at EHU 11.26). This is an important constraint for Hume because it allows him to ask who has ever perceived an instance of a power or force in action. This is crucial for Hume’s attack on theoretical and invisible entities.