 Most of those who have argued that metaphysical explanation is deductive-nomological have tended to defend a comparatively “heavyweight” account of the (metaphysical) laws that metaphysical explanations involve, and so have opted for a realist separatist version of the account. Laws, on this view, are understood as something more or other than the Humean regularities they entail, and in at least some cases involve or reduce to facts about an underlying “construction” relation or essence (e.g., Glazier 2016; Kment 2014; Wilsch 2015). For more on the nature of “laws of metaphysics”, see, e.g., Sider (2011: sect. 12.4) and Rosen (2006; 2017). For a comparatively speaking less heavyweight account of the nature of the laws that feature in metaphysical explanation—one according to which such laws are nothing but “counterfactual-supporting general principles” and therefore “inclusive” in the sense of being neither necessarily fundamental nor necessarily exceptionless—see Schaffer (2017). See also Woodward and Hitchcock (2003).