Exclusion Internalized: The Necessity of the Powers-Based Response in Russellian Monism

Abstract

Abstract Russellian monism faces an internal analogue of Kim's exclusion problem: if the phenomenal quiddities that ground the dispositional profile of matter can vary or vanish without any difference to that profile, they appear causally idle, and consciousness collapses into epiphenomenalism. This paper does not add a further defence. It argues that the two most developed anti-exclusion strategies from the non-reductive physicalist debate — Bennett's appeal to modally dependent overdetermination, and List and Menzies' difference-making account — cannot be transferred to the internal problem, and that they fail for a single reason. Bennett's strategy requires a modal dependence between the two candidate causes that the monist's contingency-of-grounding thesis expressly denies; without it, the monist's predicament satisfies Bennett's own criterion for malign overdetermination. List and Menzies' test does not merely fail but reverses: it credits the dispositional profile and demotes the quiddity, yielding a proof of epiphenomenalism. Both failures trace to the contingency thesis, a form of quidditism that is the structural counterpart, inside Russellian monism, of the distinctness premise in Kim's argument. The whole family of compatibilist responses turns on a modal entanglement that the contingency thesis withdraws, so none transfers. The powers-based views — the powerful-qualities identity and the necessitarian phenomenal-powers view — are therefore not one option among several but the only coherent response, since they alone remove the contingency on which every version of the problem depends. The conclusion is robust across two readings of the excluding premise, which differ only over which powers-based view is thereby obligatory. The paper thus derives, rather than recommends, the powers-based treatment.