Full Idea
Independent of conventions, no definite sense can be given to the notion of 'the same stuff as this'. So reference-fixing must include some principle of individuation to determine the aspects of sameness for the identity referred to.
Gist of Idea
We aren't clear about 'same stuff as this', so a principle of individuation is needed to identify it
Source
Alan Sidelle (Necessity, Essence and Individuation [1989], Ch.6)
Book Reference
Sidelle,Alan: 'Necessity, Essence and Individuation' [Cornell 1989], p.200
A Reaction
Is he really saying that we don't understand 'same stuff as this'? Surely animals can manage that, and they are not famous for their conventions. Sidelle has fallen into the sortalist trap, I think.