Abstract

In Reasons and Persons Derek Parfit grapples with a number of mesmerizing sorites-like arguments, which lead us ‘by what seem innocent steps, to absurd conclusions’. His spectrum argument for the Repugnant Conclusion, appealing to slight differences in quality of life, is a notable example. Several authors have defended the Dismissive Analogy, according to which, since such paradoxical spectrum arguments are structurally analogous to sorites arguments, the correct solution to spectrum arguments will be structurally analogous to the correct solution to sorites arguments. In this paper, I argue that existing responses to the Dismissive Analogy, which attempt to draw structural disanalogies between sorites arguments and spectrum arguments, are unsuccessful. I argue that the Dismissive Analogy nonetheless fails, as there are at least two substantive disanalogies between these arguments. Structurally analogous solutions to these paradoxical arguments can be of differential plausibility, depending on whether the sharpness or vagueness they entail is confined to our representations or located in the world. Moreover, sharpness or vagueness in the world can be more or less acceptable, depending on its ‘metaphysical depth’.