 Determinables as incoherent. Armstrong (1978a: 106–7, 117–18) argues that determinables are incoherent, in constituting the respect in which associated determinates are both similar and dissimilar (see Elder 1996: 151 for  discussion).[20]  Fales (1990: 174) sees the concern as incorrectly presupposing that determinables are second-order properties of or relations between determinates. Massin (2013) thinks the concern depends on whether the similarity at issue is exact or inexact; if inexact, there is no problem (“[t]wo things that are imperfectly similar in their colour can be imperfectly dissimilar in their colour”) but if exact—in virtue, e.g., of determinables being exactly similar constituents of determinates—then incoherence follows, since differences between determinates must be explained by what “remains” once the shared determinable is removed, but we cannot make sense of such removal.