The Pensive Image introduces a new artistic category of “pensive images” that asks viewers to philosophize instead of calling for interpretation. While before the 19th century, art and philosophy were seen as sister arts, with the birth of art history as a discipline, the philosophical dimension of art has since been largely ignored. This book argues that art is a form of thinking, and that images trigger thought rather than offering a meaning or narrative. Coupling early modern works to modern and contemporary art, the book gives in five chapters an in-depth, transhistorical account of how art has assisted in shaping philosophical concepts: how interior painting mirrors interiority; how landscapes provide mental trajectories, and how mirroring in painting leads to self-reflection. Its ultimate aim is to call for a philosophical art history on the basis that all art, in Wunderkammern or elsewhere, evoke wonder, which is the origin of all thinking.