Full Idea
Many of the kinds we theorize about and experiment on today simply do not have essences. We can distinguish 'essence kinds', such as electrons, and 'cluster kinds', such as biological species.
Gist of Idea
Some kinds, such as electrons, have essences, but 'cluster kinds' do not
Source
Anjan Chakravarrty (Inessential Aristotle: Powers without Essences [2012], 2)
A Reaction
This is an important point for essentialists. He offers a strict criterion, in Idea 15145, for mind membership, but we might allow species to have essences by just relaxing the criteria a bit, and acknowledging some vagueness, especially over time.
Related Idea
Idea 15147 Cluster kinds are explained simply by sharing some properties, not by an 'essence' [Chakravartty]