 Not all works of conceptual art evokes mental imagery this way. One exception would be Robert Barry’s All the things I know, which is nothing but the following sentence written on the gallery wall with simple block letters: “All the things I know but of which I am not at the moment thinking – 1:36 PM; June 15, 1969”. It would be difficult to argue that this work has much interest in enticing the viewer’s mental imagery. But it is not easy to find an example of a conceptual artwork where mental imagery plays no role. So in the vast majority of conceptual artworks, mental imagery is a necessary feature of appreciating the artwork.