On Individuating Contingently Non-Concrete Objects

Abstract Timothy Williamson is known for defending the view that second-order S 5 system axiomatized with Barcan Formulae gives us the most sensible doctrine for metaphysical modality. Barcan Formulae require a constant domain of quantification in which absolutely everything is necessary. Among the objects that constitute this ‘everything’ we find contingently non-concrete objects . These objects do not occupy spatiotemporal coordinates and exist just in the logical sense of ‘exist’ defended by Williamson. In this paper, I try to characterize these sui generis objects arguing that the only properties we can use to individuate them are non-qualitative, including some modal properties. This is so because, as I show in the paper, if we try to individuate contingently non-concrete objects using qualitative properties we incur into the predicative reading of expressions like ‘possible X’ rejected by Williamson.