Look around you: I mean it. Pause, for a moment and look around the room that you are in. I’m going to point out something so obvious that it tends to be forgotten. It’s this: that everything you can see, including the walls, was, at some point, imagined. Someone decided it was easier to sit on a chair than on the ground and imagined the chair. Someone had to imagine a way that I could talk to you in London right now without us all getting rained room and the things in it, and all the other things in this building, this city, exist because, over and over and over, people imagined things.