Full Idea
In the categoricalist view, the essential properties of a natural property are limited to its essentially being itself and not some distinct property.
Gist of Idea
The categoricalist idea is that a property is only individuated by being itself
Source
Alexander Bird (Nature's Metaphysics [2007], 4.1)
Book Reference
Bird,Alexander: 'Nature's Metaphysics' [OUP 2007], p.67
A Reaction
He associates this view with Lewis (modern regularity view) and Armstrong (nomic necessitation), and launches a splendid attack against it. I have always laughed at the idea that 'being Socrates' was one of the properties of Socrates.