Quote by Philip Pullman
One moment several things are possible, the next moment only one happens, and the rest don't exist. Except that other worlds have sprung into being, on which the did happen.
Summary
This quote suggests that in any given moment, there may be multiple possibilities, but only one actually materializes. The rest of the possibilities cease to exist, except in parallel universes where they do occur. It implies the existence of alternative outcomes and highlights the idea that each choice or decision leads to different branches of reality, creating a web of parallel worlds where various possibilities unfold.