This article considers the practice of witness in the world—witness to the world—in particular the character and temper, nature and purpose, significance and resonance of "moral witness," a kind of ideal type, as conceived by the philosopher Avishai Margalit It proposes that the artist plays an important role as a moral witness and that the work of art itself performs the same function, even after the fact—the phenomenon of "postwitness." In this context, it identifies an ethics of precision or exactitude and adduces a variety of exemplars, ranging from poetry to photography, including Shot at Dawn (2014), a suite of landscape photographs which are also war photographs and memorial photographs, and acts of moral witness, by Chloe Dewe Mathews.