 Proponents of such accounts typically offer some specific account of the relation at issue, aimed at rendering it plausible that the features at issue might be type-but-not-token distinct. Cynthia and Graham Macdonald (1986, 1995) suggest that higher-level features are determinables of lower-level physical features and determinable types are reducible to disjunctions of determinate types. Given this combination of views, higher-level determinable features are type-distinct from associated lower-level determinate features (since a disjunctive type is not identical to any one disjunct type), but every instance of a higher-level determinable feature is token-identical with some lower-level determinate feature (since instances of disjunctive types are token-identical with instances of some or other disjunct type). Some critics object that higher-level features are not appropriately modeled as determinables of lower-level physical determinates (Ehring 1996), or that determinables cannot be reductively analyzed in terms of determinates (Wilson 2012).