 Armstrong implicitly assumes that categorical properties are non-Meinongian. This brings under the spotlight the question of how to characterise the essences of categorical properties in a way that renders them non-Meinongian. Towards this end, most categoricalists including Armstrong subscribe to quidditism, according to which the essence of a property is constituted by its internal or self-contained nature, that is, what is called quiddity, that is only contingently related to the specific theoretical roles it plays (Armstrong 1989, 1997; Lewis 2009). (Despite this move, Handfield (2005) criticises, Armstrong is still susceptible to the ‘Meinongianism objection’ as his nomic necessitation relation \(N\) is constituted by a relation to counterfactual states of affairs.) Armstrong (1997, p. 80) thus says, ‘properties are self-contained things, keeping themselves to themselves, not pointing beyond themselves to further effects brought about in virtue of such properties’. Then what exactly is this internal or self-contained nature? Given that theoretical roles are ruled out as being merely contingently related to it, there seems to be very little to be said about it. Thus Black (2000, p. 91) says that, according to Lewis who accepts quidditism, ‘Just about all there is to a Humean fundamental quality is its identity with itself and its distinctness from other qualities’. On quidditism, the essence of a property puts no constraint whatsoever on how its instances are disposed to act or react under various circumstances. This is why quidditism goes along with categoricalism which asserts that properties have no dispositional essences.