Full Idea
We can remain anti-essentialist while allowing some necessary properties: those essential to everything (self-identity), relational properties (being what it is), and world-indexed properties (being snub-nosed-only-in-Kronos).
Gist of Idea
Necessarily self-identical, or being what it is, or its world-indexed properties, aren't essential
Source
Robert C. Stalnaker (Anti-essentialism [1979], p.73)
Book Reference
Stalnaker,Robert C.: 'Ways a World Might Be' [OUP 2003], p.73
A Reaction
[a summary] He defined essential properties as necessary properties (Idea 12761), and now backpeddles. World-indexed properties are an invention of Plantinga, as essential properties to don't limit individuals. But they are necessary, not essential!
Related Idea
Idea 12761 An essential property is one had in all the possible worlds where a thing exists [Stalnaker]