The purpose of this paper is to better understand what ontologists are doing when they ask questions about the categories of the world. I will take Cumpa’s attempts to find out the fundamental structure of the world as a case-study. In one of his latest paper (Cumpa 2014), he conceives the classical ontological question about the existence of the fundamental categories of the world (what are the fundamental categories of the world?) as a question about the category able to unify the two Sellarsian images of the world: the manifest and scientific images, considered as two different languages. According to him, the only category with such an explanatory power is the category of ‘facts’ (or ‘state of affairs’): the fundamental cate-gory of what he calls ‘the metaphysical language.’ I will argue that if Cumpa takes the latter to be a broader language or framework, in Carnap’s terms, common to both the ordinary and the scientific ones, then his proposal turns out to be rather problematic (as they are ultimately ‘incommensurable’). On the other hand, if he understands it as external to both of them, then his solution ends up being mean-ingless and devoid of any cognitive content, with at best a practical character and/or an expressive function.