Equifelicity: The Threshold Constraint as Presupposition of Justice develops a post-Marxist theory of distributive justice built around a single foundational claim: before any discourse about how to distribute goods can begin, a prior condition must be guaranteed — that no member of the polity is located at or beyond the threshold of morally inadmissible suffering (S*), the point at which agential functioning collapses and the subject can no longer receive, evaluate, or respond to justifications at all. The paper makes three original contributions. First, it operationalizes S* through five diagnostic criteria (deliberative incapacity, projectual discontinuity, catastrophic exit pressure, voice suppression, temporal collapse) aligned with clinical instruments (DSM-5, Istanbul Protocol) and empirical research on poverty and extreme suffering (Desmond, Mullainathan/Shafir), providing a methodology for borderline cases including burden asymmetry, multi-stakeholder assessment, and trajectory priority. Second, it presents a transcendental argument — grounded in Forst's justificatory practice account and defended against non-justificationist objections from Raz and Enoch through three concrete cases (severe depression, torture, chronic housing precarity) — demonstrating that social arrangements which produce S* defeat their own normative standing as theories of justice. Third, it develops the institutional implementation of the Lexical Shield through three concrete scenarios (Basic Income Plus, Housing-First Plus, Integrated Capability Insurance) with cost-benefit analysis and monitoring mechanisms, drawing on RCT evidence from the At Home/Chez Soi trial and Nordic welfare state comparative data. The paper integrates the Marxian principle of need (reconstructed via Wiggins and Braybrooke's needs/preferences distinction) with capabilities theory (Sen, Nussbaum), corrosive disadvantage analysis (Wolff and de-Shalit), sufficientarianism (Frankfurt, Crisp, Shields, Casal), and relational egalitarianism (Anderson, Scheffler) into a two-level architecture: threshold equifelicity as lexical constraint, needs equifelicity as organizational principle above the threshold. The paper is a companion to "The Ferrari Paradox: Subjective Need, Maximum Suffering, and Lexical Priority in Distributive Justice."
Tommaso Biagi (Sun,) studied this question.