Full Idea
Internal relations are determined either by the mere existence of the things they relate, or by their intrinsic characters, or they supervene on the intrinsic characters of the things they relate.
Gist of Idea
Internal relations are fixed by existences, or characters, or supervenience on characters
Source
Fraser MacBride (Relations [2016], 3)
Book Reference
'Stanford Online Encyclopaedia of Philosophy', ed/tr. Stanford University [plato.stanford.edu], p.5
A Reaction
Suggesting that they 'supervene' doesn't explain anything (and supervenience never explains anything). I vote for the middle one - the intrinsic character. It has to be something about the existence, and not the mere fact of existence.