Full Idea
I see no reason for thinking essentialism unintelligible, but a chief perplexity is the obscurity of the grounds on which ratings of attributes as essential or accidental are to be made.
Gist of Idea
The difficulty in essentialism is deciding the grounds for rating an attribute as essential
Source
Richard Cartwright (Some Remarks on Essentialism [1968], p.158)
Book Reference
Cartwright,Richard: 'Philosophical Essays' [MIT 1987], p.158
A Reaction
In that case some of us younger philosophers will have to roll up our sleeves and tease out the grounds for essentialism, starting with Aristotle and Leibniz, and ending with the successes of modern science.