Grounding, necessity, and relevance

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.