Full Idea
The closeness of possible worlds should be determined by similarity in the intrinsic constitution of whatever object it is whose potentialities are at issue.
Gist of Idea
Closeness of worlds should be determined by the intrinsic nature of relevant objects
Source
Barbara Vetter (Essence and Potentiality [2010], §3)
A Reaction
Nice thought. This seems to be the essentialist approach to possible worlds, but it makes the natures of the objects more fundamental than the framework of the worlds. She demurs because there are also extrinsic potentialities.