What would a visual image of a philosophical idea look like? Aren’t philosophical concepts, by virtue of their very abstractness, incapable of being rendered visually? These were some of the questions raised in the recent exhibition Mel Bochner: Illustrating Philosophy, which examined a specific project by the renowned conceptual artist. In the catalogue, Professor of Philosophy Thomas E. Wartenberg explores prints and drawings by Bochner that were published as illustrations to the 1991 Arion Press edition of Ludwig Wittgenstein’s On Certainty. Wartenberg shows how Bochner translates Wittgenstein’s revolutionary claims about knowledge and doubt into visual images.