Full Idea
If knowledge of essence were by acquaintance of a special kind of entity, we would doubt our ability to grasp the essence of things. For what faculty could be involved in this special kind of acquaintance?
Gist of Idea
If we must know some entity to know an essence, we lack a faculty to do that
Source
E.J. Lowe (What is the Source of Knowledge of Modal Truths? [2013], 7)
Book Reference
-: 'Mind' [-], p.28
A Reaction
This is Lockean empirical scepticism about essences, but I take the view that sometimes you can be acquainted with an essence, but more often you correctly infer it from you acquaintance - and this is just what scientists do.