Full Idea
It does not seem altogether arbitrary to treat the structure of the world (the 'form' of the world) in a different way to the nodes in the structure (the 'matter' of the world).
Gist of Idea
We can treat the structure/form of the world differently from the nodes/matter of the world
Source
John Hawthorne (Causal Structuralism [2001], 2.5)
Book Reference
Hawthorne,John: 'Metaphysical Essays' [OUP 2002], p.223
A Reaction
An interesting contemporary spin put on Aristotle's original view. Hawthorne is presenting the Aristotle account as a sort of 'structuralism' about nature.