Grounding and defining identity

I systematically defend a novel account of the grounds for identity and distinctness facts: they are all uniquely zero-grounded. First, the Null Account is shown to avoid a range of problems facing other accounts: a relation satisfying the Null Account would be an excellent candidate for being the identity relation. Second, a plenitudinist view of relations suggests that there is such a relation. To flesh out this plenitudinist view I sketch a novel framework for expressing real definitions, use this framework to give a definition of identity, and show how the central features of the identity relation can be deduced from this definition.