 What sort of claim is it, then? Some suggest that this and similar claims are grounding claims, where grounding is understood to be a form of constitutive (as opposed to causal or probabilistic) determination or explanation. The point of departure for theorizing about grounding is that there are a variety of claims—claims we make in ordinary life as well as ones we make in the context of doing philosophy—that are best interpreted as being claims about what grounds what. As for metaphysics in particular, some claim that grounding plays a central role in the enterprise properly conceived. Schaffer, for example, writes that “metaphysics as I understand it is about what grounds what” rather than what exists (2009: 379). And, according to Fine, questions about what grounds what are central to what he calls realist metaphysics, which concerns not just the nature of things but whether they are real; “Indeed”, Fine writes, “if considerations of ground were abolished, then very little of the subject would remain” (2012a: 41).