The determination thesis is the idea that art-ontological facts are determined by the folk ontological conception of artworks embedded in our artistic practices. From this thesis, descriptivism in the metaontology of art has been often characterized as the view that the task of art-ontology is to describe that folk conception. Amie Thomasson and Andrew Kania provide two paradigmatic accounts within this path. In this paper, I argue that this descriptivist approach is ungrounded because the determination thesis suffers from presupposition failure. (...) It presupposes that, whenever there is a practice of producing and appreciating artworks, there is also a folk ontological conception about those artworks. This presupposition, an implicit premise in Thomasson's and Kania's accounts, will be revealed as false, paying attention to the way artistic practices have evolved. I will conclude that descriptivism should abandon this approach and embrace metaontological realism if it aims to be a plausible view. (shrink)