 Much recent work on categories has been influenced by skepticism about the possibility of offering a system of ontological categories. Difficulties like those mentioned above have undermined the idea that a uniquely true and comprehensive system of ontological categories can be found. The skepticism that comes from noting the proliferation of category systems is compounded by general skepticism about metaphysics. In some cases this has come from imputations of logical positivists that all metaphysical talk is nonsense. More recently, the skepticism has arisen from general doubts about the epistemology of metaphysics (Bennett 2009, Kriegel 2013, Thomasson 2015), as well as more specific doubts that we can make sense of the idea that the world has a distinctly ‘ontological structure’, or that we could discover what that structure is.