Dreaming is a form of mental activity that takes place during the act of sleep. Dreams invoke strong emotions within the dreamer, such as ecstasy, joy and terror, dredging up deep emotions and premonitions that reflect tellingly upon the dreamer. Subjects one might conceal during waking hours emerge in sleep to haunt and arouse the dreamer. It is most likely due to this heightened emotional state that dreams are used so often within Gothic Literature. By invoking dream states within their characters, authors are able to illustrate emotions on a more unmediated and, oftentimes, terrifying level. Dreams reveal to the reader what the character is often too afraid to realize about himself or herself. Dreaming also has an ancient relation with the act of foretelling wherein the future is glimpsed in the dream state.
The actual term nightmare seems to be a bastardization of the Old Norse and Anglo-Saxon term mara. A mara is defined as a demon which sits upon the chests of sleepers and brings bad dreams. Most cultures seemed to characterize nightmares as being caused by demons; for example, in Germany the demon is known as an Alp, in relation to elf. Etymological confusion (and play) led English writers and painters to portray graphically the nightmare as a night + horse (mare): see Fuseli's famous example.
An important point concerning the dream state was proposed by Sigmund Freud at the start of the 20th century. Freud believed that a unique mental process is used within dreams that is rarely activated during the waking hours. He defined this state as the "primary process" and theorized that this state was marked by a more primitive thought process ruled by the emotions. This theory helps explain the widespread occurrence of dreams in Gothic Literature as a state during which characters express their deepest emotions of horror and terror. Freud essentially "psychologizes" the older, folk (and still prevalent) tradition that dreams foretell future events: what the ancients widely and superstitiously regarded as portents, Freud read as telling illuminations of the buried psychic life of individuals--and their success in dealing with these dream-state phantoms might very well direct their future success in life.
Examples: Ancient literatures contain many examples of dreams with prophetic content, such as Clytemnestra's dream of a viper at her breast (signifying Orestes' return) in The Libation Bearers. Perhaps the most famous Gothic example occurs in Shelley's Frankenstein. Following two years of difficult work, Victor Frankenstein re-animates a once dead corpse. However, the elation he expected to feel at this conquest does not occur because he is horrified at the monster's loathsome appearance. Exhausted and saddened by his prolonged work and dashed expectations, he falls into a dream state that begins with his kissing of Elizabeth, his love. However, this kiss changes her in the most drastic way as she transforms into the rotting corpse of Caroline, Victor's dead mother. Upon awakening from this horrifying dream, Victor finds himself staring into the face of the monster he has created. Multiple interpretations of this dream exist, most linking Victor's forbidden appropriation of the female act of creating life to the women in his life; it also is prophetic in a way, signalling the eventual death of Elizabeth. On a horrifying (if crude) level of psychoanalytic interpretation, the dream can also be read as Mary Shelley's nightmare confrontation with her own mother, who died giving her birth.
Within Stephen King's novel Bag of Bones, an author named Mike Noonan is plagued with dreams. These dreams involve the death of his wife as well as frightening visions of the summer home that he now inhabits full time. They are also interspersed with nightmares, acts of sleepwalking, and glimpses of the future. Eventually, through the recurrence of these dreams, Noonan is able to discover the events surrounding the death of his wife as well as a dark fact concerning his summer home that was secreted by the entire town. Finally, Noonan's glimpses of the future within the dreams enable him to save the life of an innocent child from an avenging spiritual curse.
Courtesy of Douglass H. Thomson, Department of Literature and Philosophy, Georgia Southern University
See also: workings of the mind
The Monkish Mysteries; or, the Miraculous Escape: Containing the History and Villainies of the Monk Bertrand, the Detection of His Impious Frauds, and Subsequent Repentance and Retribution., Elizabeth Meeke