Universalization and altruism

Abstract

The \(\kappa\)-universalization of a symmetric game is the game in which each player considers that any other player chooses with probability \(\kappa\) the same stategy as she. To any normal form game, we associate the symmetric two-stage game in which, in a first stage, the roles to be played in the base game are randomly assigned. We show that any pure strategy equilibrium of the \(\kappa\)-universalization of this extended game is an equilibrium of the base game played by altruistic players (“ex ante Homo Moralis equilibrium is altruistic”), and that the converse is false. The paper presents the implications of this remark for the philosophical nature of ethical behavior (Kantianism behind the veil of ignorance implies but is stronger than altruism) and for its evolutionary foundations.