Full Idea
Essentialist metaphysics seem to require that there be at least two kinds of properties in nature: dispositional properties (causal powers, capacities and propensities), and categorical ones (spatiotemporal and numerical relations).
Gist of Idea
Essentialism needs categorical properties (spatiotemporal and numerical relations) and dispositions
Source
Brian Ellis (The Metaphysics of Scientific Realism [2009], 3)
Book Reference
Ellis,Brian: 'The Metaphysics of Scientific Realism' [Acument 2009], p.63
A Reaction
At last someone tells us what a 'categorical' property is! Couldn't find it in Stanford! Bird and Molnar reject the categorical ones as true properties. If there are six cats, which cat has the property of being six? Which cat is 'three metres apart'?