Full Idea
In my view 'being a methane molecule' is not a property name, but a predicate that is constructed out of a natural kind name, and so pretends to name a property.
Gist of Idea
'Being a methane molecule' is not a property - it is just a predicate
Source
Brian Ellis (Scientific Essentialism [2001], 2.03)
Book Reference
Ellis,Brian: 'Scientific Essentialism' [CUP 2007], p.68
A Reaction
I can't tell you how strongly I agree with this. How long have you got? This is so incredibly right that... You get the idea. He observes that such properties cannot be instantiated 'in' anything.