Abstract
Dispositions may be identical to their categorical bases but should we say, with Quine, that all properties are categorical or, with Popper, that all properties are dispositional? Both positions make implicit claims of ontological reduction but if this consists in nothing more than identity then, identity being a symmetrical relation, neither categorical nor dispositional monism is provided. A supervenience relation may be thought decisive, but if the identities are token- token, reduction is ruled out; if the identities are type- type there is no direction of supervenience hence no determination of reduction. It is concluded that both ontologies have been argued inadequately