Full Idea
Counterpart Theory essentially reduces all problems about counterfactual identity to problems about choosing appropriate similarity relations. That is, Counterpart Theory essentially eliminates problems of counterfactual identity as such.
Gist of Idea
Counterparts reduce counterfactual identity to problems about similarity relations
Source
Peter van Inwagen (Material Beings [1990], 14)
Book Reference
Inwagen,Peter van: 'Material Beings' [Cornell 1995], p.167