 The concept of ground is supposed to do the trick. Ground is regarded as a primitive (Fine 2001). As a consequence, instead of giving an analysis of the concept of ground, philosophers have studied the structural features of ground – it is transitive, irreflexive, asymmetric, and it generates hyper-intensional contexts (Fine 2012; see also the contributions in Correia and Schnieder 2012). But if this notion is primitive, how do we get access to it? After all, ‘ground’ is, like ‘reduction’, a philosophical term; reflection on ordinary usage will not give access to its meaning in philosophical contexts.