 Problems in the ontology of art include the ontological categories into which artworks fall, the unity or diversity of kinds of entities within artistic domains and across domains (e.g., in painting, sculpture, music, dance), the individuation of particular artworks, the definition of art in general, and the dynamic changes in artistic categories. See entries on the  definition of art,  history of the ontology of art,  the philosophy of music,  the philosophy of dance,  conceptual art,  and  the philosophy of digital art.