This chapter describes that the search for truthmakers for metaphysical modal claims leads to a morass of ontological and epistemological problems. It argues for a different approach to understanding metaphysical modal claims: thinking of them not as serving to describe modal features of the world, but rather serving a normative function of conveying semantic rules and their consequences. Understanding metaphysical modal claims in this way, the chapter enables us to demystify the ontology and epistemology of modality, and to clarify the epistemology of metaphysics. One prominent alternative to heavyweight modal realism is David Lewis’s possible worlds realism. Although the primary function of metaphysical modal claims is to convey semantic rules rather than to report metaphysical discoveries, it is still useful to do so by just using the terms, in the object language.