Full Idea
According to essentialists, the world is wholly structured at the most fundamental level into natural kinds, and the laws of nature are all determined by those kinds.
Gist of Idea
Essentialism says natural kinds are fundamental to nature, and determine the laws
Source
Brian Ellis (The Philosophy of Nature: new essentialism [2002], Ch.5)
Book Reference
Ellis,Brian: 'The Philosophy of Nature: new essentialism' [Acumen 2002], p.82
A Reaction
I am a fan of this view, despite being cautious about claims that natural kinds have necessary identity. Why are the essences active? That is the old Greek puzzle about the origin of movement. And why are natural kinds stable?