Full Idea
A second view of the principle of individuation includes criteria of distinction and persistence, but also determines the counterfactual possibilities for a thing.
Gist of Idea
Individuation may include counterfactual possibilities, as well as identity and persistence
Source
Penelope Mackie (How Things Might Have Been [2006], 8.5)
Book Reference
Mackie,Penelope: 'How Things Might Have Been' [OUP 2006], p.141
A Reaction
It would be a pretty comprehensive individuation which defined all the counterfactual truths about a thing, as well as its actual truths. This is where powers come in. We need to know a thing's powers, but not how they cash out counterfactually.