Uncertainty and Justifiability to Each Person

This paper responds to the arguments of Marc Fleurbaey and Alex Voorhoeve in “Decide as You Would with Full Information! An Argument against ex ante Pareto” (this volume). According to the ex ante Pareto principle, if an alternative has higher expected utility for every person than every other alternative, then this alternative should be chosen. Fleurbaey and Voorhoeve claim that ex ante Pareto is not just inconsistent with impersonal distributive principles such as telic egalitarianism or prioritarianism; it also violates a broadly contractualist criterion of moral rightness, according to which an action is right if and only if it is justifiable to each person. I argue that Fleurbaey and Voorhoeve’s main argument against ex ante Pareto fails. The Principle of Full Information, on which it is based, is either unsound, or else cannot settle the debate between defenders and opponents of ex ante Pareto. I conclude that while outcome-based moral principles, such as telic egalitarianism or prioritarianism, do indeed militate against ex ante Pareto, there is no objection to this principle from the vantage point of justifiability to each person.