Description invariance: a rational principle for human agents

Abstract This article refines a foundational tenet of rational choice theory known as the principle description invariance. Attempts to apply this human agents with imperfect knowledge have paid insufficient attention two aspects: first, agents’ epistemic situations, i.e. whether and when they recognize alternative descriptions an object be equivalent; second, individuation objects description, count same or different. An important consequence is that many apparent ‘framing effects’ may not violate invariance, subjects these effects irrational.