Could be a Philip K. Dick story, but I also think it’s an inherently interesting question. If something happens in a dream that causes you to laugh, is it really funny? What if you can remember the scenario afterwards and your waking self doesn’t find it funny, or coherent? Once or twice when this has happened to me, my laughter wakes me up just enough to remember the dream. In the case that I remember, it wasn’t a funny narrative or wordplay that made me laugh, it was something more like a spatial or conceptual pun. It doesn’t appear to me a subject that many have pondered, however, if you want to understand the state of terror we sometimes experience, you need look no farther than sleep paralysis.