Grounding, necessity, and relevance

Abstract Grounding necessitarianism (GN) is the view that full grounds necessitate what they ground. Although GN has been rather popular among philosophers, it faces important counterexamples: For instance, A = Socrates died fully grounds C = Xanthippe became a widow. However, A fails to necessitate C: A could have obtained together with B = Socrates and Xanthippe were never married, without C obtaining. In many cases, the debate essentially reduces to whether A indeed fully grounds C–as the contingentist claims–or if instead C is fully grounded in A + , namely A plus some supplementary fact S (e.g. Xanthippe was married to Socrates)–as the necessitarian claims. Both sides typically agree that A + necessitates C, while A does not; they disagree on whether A or A + fully grounds C. This paper offers a novel defence of the claim that, in these typical cases, unlike A + , A fails to fully ground C–thereby bringing further support to GN. First and foremost, unlike A + , A fails to fully ground C because it fails to contain just what is relevant to do so, in two distinct senses– explanatory and generative relevance. Second, going for A, rather than A + , as a full ground undermines not just grounding necessitarianism , but modally weaker views which even contingentists may want to preserve.