In this article, I argue that our ontology of art has undergone a major change in the course of modern history. While we currently think of artworks as parts arranged in a certain way, there was a time when artworks were thought of as metaphysically more akin to ordinary artefacts such as tables and chairs; that is, as wholes having replaceable parts. This change in our ontology of art is reflected in our approach to art restoration. But what explains the (...) change? I will suggest that the change took place because of a change in our conception of the function of art. More specifically, I will suggest that we have started to think of artworks as parts arranged in a certain way, because we have started to think of artworks as having, primarily, an aesthetic function. (shrink)