Ex Ante Pareto and the Opaque-Identity Puzzle

Abstract

Anna Mahtani describes a puzzle meant to show that the Ex Ante Pareto Principle is incomplete as it stands and, since it cannot be completed in a satisfactory manner, decades of debate in welfare economics and ethics are undermined. In this paper, we provide a better solution to the puzzle which saves the Ex Ante Pareto Principle from this challenge. We also explain how the plausibility of our solution is reinforced by its similarity to a standard solution to an analogous puzzle in quantified epistemic logic. We also show that even if the puzzle were to remain unsolved, its impact on welfare economics and ethics would be limited.