Full Idea
Because there cannot be relations without terms, in a meta-physic that makes first-order tropes the terms of all relations, relational tropes must belong to a second, derivative order.
Gist of Idea
Relations need terms, so they must be second-order entities based on first-order tropes
Source
Keith Campbell (The Metaphysic of Abstract Particulars [1981], §8)
Book Reference
'Properties', ed/tr. Mellor,D.H. /Oliver,A [OUP 1997], p.138
A Reaction
The admission that there could be a 'derivative order' may lead to trouble for trope theory. Ostrich Nominalists could say that properties themselves are derivative second-order abstractions from indivisible particulars. Russell makes them first-order.