The article explores the possibility of defining unaided ready-mades as objects of art. It starts from the assumption that Edmund Husserl’s notion of horizon and Arthur Danto’s notion of artworld have similar meanings. Accordingly, it argues that unaided ready-mades are objects of art that appear with unique cultural horizons called artworlds. The aim is to show that the artworld is an external co-determining horizon that is sufficient for determining unaided ready-mades to be artworks.