Full Idea
In the sphere of scientific enquiry the distinction between real and nominal essence tends to disappear; the scientist's classification of things is intended to be in terms of their real essences.
Gist of Idea
In modern science, nominal essence is intended to be real essence
Source
Irving M. Copi (Essence and Accident [1954], p.716)
Book Reference
-: 'Journal of Philosophy' [-], p.716
A Reaction
Thus we have disputes over what is the 'real' classification of natural kinds such as animals. There is not much point in a classification system that does not at least reflect some aspects of reality.