 One way is to deny dreams involve presence or the feeling of being in a world, which many believe is central to waking perception. Imagination theorists compare the sense in which we feel present in our dreams to cognitive absorption, as when we are lost in a novel, film, or vivid daydream (Sartre 1940; McGinn 2004; but see Hering 1947; Globus 1987). Some argue that reflexive consciousness or meta-awareness (as in lucid dreams) interrupts cognitive absorption and terminates the ongoing dream (Sartre 1940), essentially denying lucid dreams are possible.