The story-maker proves a successful ‘sub-creator’. He makes a Secondary World which your mind can enter. Inside it, what he relates is ‘true’: it accords with the laws of that world. You therefore believe it, while you are, as it were, inside. The moment disbelief arises, the spell is broken; the magic, or rather art, has failed.
— from “On Fairy-Stories” (1939 essay)