One Axiom, Many Principles: A Formal Meta-Theory of Distributive Justice

Distributive justice has fragmented over more than two centuries into rival traditions — proportionalism, libertarianism, egalitarianism, contractarianism, relational equality — each defending its central principle as the universal axiom of just distribution. This paper argues that several of these principles are not competitors but domain-specific specifications of a single axiom: the Non-Harm Principle (NH), which holds that no agent may impose a loss on another without consent or adequate compensation. Using a five-variable model of moral interaction — agent, action, natural resource, state, consent — I show that the causal sources of welfare change can be partitioned into seven primitive domains, and that NH yields different distributive specifications across these domains. In particular, NH entails proportionality (PP) in cooperative-production domains and equal division (EP) in pre-existing-resource domains, both as cases of a single meta-lemma about the formal expression of moral equality. The framework does not claim to reduce all moral traditions to a single foundation; it claims something narrower and, I argue, more defensible: that within the rights-based, contractarian, and natural-law traditions — which already share NH as a common core — the apparent disagreement among Aristotelian, Lockean, Rousseauian, and Rawlsian principles can be reframed as agreement at the axiomatic level combined with disagreement about which domain a given case occupies. The central question of distributive justice thus shifts from which principle is correct to which domain does this case fall under. I conclude by clarifying the framework’s scope, the questions it does not resolve, and the role of consent in legitimating departures from the default domain rules.