Full Idea
A natural account of dependence in terms of modality and existence is that one thing x will depend on another thing y just in case it is necessary that y exists if x exists (or in the symbolism of modal logic, □(Ex→Ey).
Gist of Idea
A natural modal account of dependence says x depends on y if y must exist when x does
Source
Kit Fine (Ontological Dependence [1995], I)
Book Reference
-: 'Aristotelian Society' [], p.270
A Reaction
He is going to criticise this view (which he traces back to Aristotle and Husserl). It immediately seems possible that there might be counterexamples. x might depend on y, but not necessarily depend on y. Necessities may not produce dependence.