I dream that I’m having a lucid dream—perhaps it is lucid, for a moment—and I see, on my bedroom floor, a sandy beach that is filled with beach stones. I tell myself to pick up a stone before I lose the lucidity, as that will allow me to bring it back from the dream world. I reach for a stone, and then I seem to experience a “false awakening,” in which I am sure that I’m now awake and still have the stone in my hand. I’m thrilled to discover my apparent success at bridging the two different worlds, but later I learn that it’s not the case, and I feel a deep disappointment: I’m truly awake, and my open hand is empty.