Full Idea
'Tis necessary for me to be as I am; God and Nature has made me so: but there is nothing I have is essential to me.
Gist of Idea
Nothing about me is essential
Source
John Locke (Essay Conc Human Understanding (2nd Ed) [1694], 3.06.04)
Book Reference
Locke,John: 'Essay Concerning Human Understanding', ed/tr. Nidditch,P.H. [OUP 1979], p.440
A Reaction
This is the aspect of Locke's critique of essentialism which Leibniz particularly disliked. Locke's view still has plenty of defenders, but I take it to be wrong, and Pinker seems to suggest that empirical research is beginning to agree with me.