The conference on Metametaphysics here at ANU has just finished. It was a highly enjoyable conference, with a number of excellent talks and a good airing of the issues. Ted Sider argued for ontological realism; Steve Yablo and I set out (very different) ways of understanding how there can be no fact of the matter in some ontological debates; Amie Thomasson argued for a sort of lightweight realism where existence facts are sortal-relative and to be determined by conceptual analysis; Karen Bennett argued against Eli Hirsch's thesis that debates about composition involve verbal disputes and suggested that the right answers in the composition and coincidence debates may involve unknowable facts; and Huw Price discussed the Quine-Carnap debate over ontology, arguing that Quine's ontological realism is a lot closer to a pragmatic Carnapian view than it is sometimes taken to be. Lots of good discussion after every paper. I've put some photos online.
I've also uploaded the Powerpoint for my own talk, "Ontological Indeterminacy". There I first try to set out the issues and make some distinctions, and then try to state and defend a broadly Carnapian view where the truth-value of many ontological assertions is indeterminate. This involves a bit of semi-technical apparatus toward the end, involving "furnishing functions" that map possible worlds onto "furnished worlds" (which have built-in domains). There's even some supervaluation and some contextualism, for those who like that sort of thing. This should turn into a real paper one of these days, but in the meantime, comments are welcome.