Full Idea
We need a first convention to determine what matter constitutes objects, then a second to determine whether there are different temporal possibilities for a given object, then a third for different spatial possibilities.
Gist of Idea
Objects need conventions for their matter, their temporal possibility, and their spatial possibility
Source
Michael Jubien (Possibility [2009], 1.5)
Book Reference
Jubien,Michael: 'Possibility' [OUP 2009], p.23
A Reaction
This is building up a Quinean account of objects, as mere matter in regions of spacetime, which are then precisely determined by a set of social conventions.