Full Idea
For Locke the real essence of a thing is a set of properties which determine all the other properties of that thing [3.3.15], so essential properties are not retained during any change, and there is no real knowledge of the essence of things.
Gist of Idea
Locke's essences determine the other properties, so the two will change together
Source
report of John Locke (Essay Conc Human Understanding (2nd Ed) [1694], 3.03) by Irving M. Copi - Essence and Accident p.712
Book Reference
-: 'Journal of Philosophy' [-], p.712
A Reaction
Although I like the Aristotelian view, this account of Locke's must be taken seriously. Compare Idea 12304. If Aristotelian essence founds scientific knowledge, then a thing with varying behaviour has a varying essence.
Related Idea
Idea 12304 Aristotelian essence is retained with identity through change, and bases our scientific knowledge [Aristotle, by Copi]