Seminar: Metaontology

First-order ontological debates concern whether objects of various sorts exist, for instance numbers, universals, composite material objects, etc.  This seminar will examine the status of those debates.  When one philosopher says that numbers exist, and another says that numbers do not exist, what exactly are they disagreeing about?  About some "deep matter of fact", or only about how to talk?  Could it be indeterminate who is correct?  How do we decide who is correct?