A dream is a succession of images, ideas, emotions, and sensations that usually occur involuntarily in the mind during certain stages of sleep. Humans spend about two hours dreaming per night, and each dream lasts around 5 to 20 minutes, although the dreamer may perceive the dream as being much longer than this.

The mind is the totality of psychological phenomena, including thought, perception, emotion, motivation, memory, and learning. It encompasses both conscious processes, through which individuals are aware of external and internal circumstances, and unconscious processes, which can influence individuals without their awareness. Traditionally, minds were often conceived as separate entities that can exist on their own but are more commonly understood as features or capacities of other entities in the contemporary discourse. The mind plays a central role in most aspects of human life but its exact nature is disputed; some theorists suggest that all mental phenomena are private and directly knowable, transform information, have the ability to refer to and represent other entities, or are dispositions to engage in behavior.