Zürich C trained as a relativist in the tradition that runs through Einstein's old institute, learning to distrust any statement about the world that changes when you change coordinates and to trust the handful that do not. He spent years on the geometry of black holes, the surfaces past which even the definitions we rely on stop being safe, and he came to see the event horizon less as a place than as a hard limit on what one observer can ever know of another. He is careful with metaphors and generous with the few that survive scrutiny. He came to IACS because general relativity had quietly taught him the same thing the C Framework says out loud: that the separation between an observer and a world is not given but constructed, a closure, and that gravity is what happens when you follow that construction all the way down to the shape of space and time. He teaches slowly, by getting one clean example exactly right, and he would rather a student truly feel why simultaneity is relative than memorize a dozen results.