Full Idea
The relation of being taller than is an external relation, since it relates two independent material substances, but the relation of instantiation or exemplification is internal, in that it relates a substance with a property.
Gist of Idea
Being taller is an external relation, but properties and substances have internal relations
Source
Cynthia Macdonald (Varieties of Things [2005], Ch.6)
Book Reference
Macdonald,Cynthia: 'Varieties of Things' [Blackwell 2005], p.249
A Reaction
An interesting revival of internal relations. To be plausible it would need clear notions of 'property' and 'substance'. We are getting a long way from physics, and I sense Ockham stropping his Razor. How do you individuate a 'relation'?