Leximin population ethics

This paper provides characterizations of the Critical-Level Leximin and Positional-Extension Leximin principles for social evaluation in an intertemporal framework. These rules generalize fixed-population Leximin and can compare social alternatives with different population sizes. The main axioms used in our characterizations are Hammond Equity together with Independence of the Utilities of the Dead (a plausible intertemporal consistency requirement) for the Critical-Level Leximin principles, and Positional Leximin Consistency (an axiom that allows non-constant critical levels) for the Positional-Extension Leximin principle. The performance of these principles is compared in the pure population problem and we argue that the Critical-Level Leximin principles are ethically more attractive than Positional-Extension Leximin.