Horizons have shrunk. Novelists and filmmakers seem far more at home with dystopias than with the possibility that the world might get better. The institutions that once fuelled our shared imagination have, for different reasons, given up, leaving public intellectual culture recycling old ideas, while much of politics has drifted into nostalgia.

People have always been good at imagining the end of the world, which is much easier to picture than the strange sidelong paths of change in a world without end.