Universalizability for Collective Rational Agents: A Critique of Agent-Relativism

This paper contends that a Kantian universalizability constraint on theories of practical reason in conjunction with the possibility of collective rational agents entails the surprisingly strong conclusion that no fully agent-relative theory of practical reason can be sound. The basic point is that a Kantian universalizability constraint, the thesis that all reasons for action are agent-relative and the possibility of collective rational agents gives rise to a contradiction. This contradiction can be avoided by either rejecting Kantian universalizability, the possibility of collective rational agents, or the tenability of a fully agent-relative theory of practical reason; we cannot have all three.