Full Idea
Wiggins's proposal of a predicate-modifier account is the best formal representation of essential statements. ...This simple version is perfectly adequate to represent the claim that a is essentially-F: □(a exists → a is F).
Gist of Idea
Essentialism is best represented as a predicate-modifier: □(a exists → a is F)
Source
report of David Wiggins (Sameness and Substance Renewed [2001], Ch.4) by Penelope Mackie - How Things Might Have Been 1.2
Book Reference
Mackie,Penelope: 'How Things Might Have Been' [OUP 2006], p.4
A Reaction
I suppose that is right. Having an essence is a feature of an entity, but it has to boil done to characteristics that define the entity, and which it must presumably always have. Could an entity ever lack its essence?