The Significance of Tiny Contributions: Barnett and Beyond

In a discussion of Parfit's Drops of Water case, Zach Barnett has recently proposed a novel argument against “No Small Improvement”; that is, the claim that a single drop of water cannot affect the magnitude of a thirsty person's suffering. We first show that Barnett's argument can be significantly strengthened, and also that the fundamental idea behind it yields a straightforward argument for the transitivity of equal suffering (a much stronger and more important conclusion than Barnett's). We then suggest that defenders of No Small Improvement could reject a Pareto principle that is presupposed in Barnett's argument and our developments of it. However, this does not save No Small Improvement, since there is a convincing argument against this claim that does not presuppose the Pareto principle.