Context-Dependent Betterness and the Mere Addition Paradox

Abstract

This chapter proposes a new solution to Derek Parfit’s Mere Addition Paradox. It argues that the paradox trades on an ambiguity about the context of choice. There is a sense in which all three intuitive judgments about Parfit’s case are true, namely as pairwise comparisons in a two-possible case, i.e. in a choice situation where the option set contains only these two outcomes. The air of paradox arises from the assumption that these pairwise judgments carry over to a three-possible case, in which all three outcomes are possible. But this, the chapter argues, is not the case. If sound, this argument shows how we can make sense of each of our pairwise intuitions in the Mere Addition Paradox, without incurring the cost of intransitivity within an option set. This solves the Mere Addition Paradox and blocks the argument toward the Repugnant Conclusion. Parfit’s case also holds a general lesson about the nature of value, but one that is less revisionary than some had thought. Correctly understood, Parfit’s Mere Addition Case challenges not the transitivity of the “better than”-relation, as Larry Temkin has argued, but instead a different, and less sacrosanct, idea, namely the so-called Independence of Irrelevant Alternatives principle. What Parfit’s puzzle teaches us is that betterness is sometimes context-dependent: the relative goodness of two outcomes can depend on whether or not a third outcome could have instead been chosen.