Plural Grounding and Redundancy Elimination: A Defence of the Modal Collapse Argument

Van Inwagen argued that the Principle of Sufficient Reason (PSR) implies necessitarianism, i.e., that all truths are necessary truths. Schnieder and Steinberg showed that van Inwagen’s argument fails if we apply a notion of plural grounding to the discussion of the PSR: the conjunction of all contingent truths is fully grounded in the plurality of all contingent truths. I argue that this manoeuvre fails if we accept a principle I call Redundancy Elimination. This principle follows naturally from the transitivity of grounding and rules out that a plurality of contingent truths can fully ground the plurality of all contingent truths. Nevertheless, it is weaker than a general irreflexivity principle and compatible with basic assumptions held by van Inwagen’s opponents. I conclude that a slightly modified version of van Inwagen’s argument shows that the PSR indeed implies necessitarianism.