Full Idea
For any entity of any sort, abstract or concrete, I assume there is a property of being that specific entity. For want of a better term, I will call such properties entity-essences. They are 'singulary' - not instantiable by more than one thing at a time.
Gist of Idea
Any entity has the unique property of being that specific entity
Source
Michael Jubien (Possibility [2009], 4.2)
Book Reference
Jubien,Michael: 'Possibility' [OUP 2009], p.88
A Reaction
Baffling. Why would someone who has mocked all sorts of bogus philosophical claims based on logic then go on to assert the existence of such weird things as these? I can't make sense of this property being added to a thing's other properties.