Modal comparisons across individuals require (a notion of) relative intensities

This article lays out a novel problem for theories of comparison and graded modality. Based on examples where we compare desirability across different attitude subjects — i.e. α wants φ more than β (wants φ) — and thus seem to be relating points from different scales to one another, we argue that the relevant notion of intensity of desire that is relevant in an across subject comparison can in some cases only be determined by comparing the roles that the corresponding desires play in the mental state of the subjects. We show that no (plausible extension of any) existing proposal captures such a notion of relative intensities.