Full Idea
Much of the theory of relations can be developed as a virtual theory, in which we seem to talk of relations, but can explain our notation in terms {finally] of just the logic of truth-functions, quantification and identity. The exception is ancestrals.
Gist of Idea
All relations, apart from ancestrals, can be reduced to simpler logic
Source
Willard Quine (Lecture on Nominalism [1946], §8)
Book Reference
'Oxford Studies in Metaphysics vol.4', ed/tr. Zimmerman,Dean W. [OUP 2008], p.14
A Reaction
The irreducibility of ancestrals is offered as a reason for treating sets as universals.