Full Idea
Categorical properties do not have their dispositional characters modally fixed, but may change their dispositional characters (and their causal and nomic behaviour more generally) across different worlds.
Gist of Idea
Categorical properties are not modally fixed, but change across possible worlds
Source
Alexander Bird (Nature's Metaphysics [2007], 3.1)
Book Reference
Bird,Alexander: 'Nature's Metaphysics' [OUP 2007], p.44
A Reaction
This is the key ground for Bird's praiseworth opposition to categorical propertie. I take it to be a nonsense to call the category in which we place something a 'property' of that thing. A confusion of thought with reality.