Gothic double
The Gothic double is a motif in literature which refers to the polarity of good and evil within a character. Closely linked to the Doppelgänger, a term which first appeared in the 1796 novel "Siebenkas" by Johann Paul Richter, the double figure emerged in Gothic literature in the late 18th century due to a resurgence of interest in mythology and folklore which explored notions of duality, such as the fetch in Irish folklore which refers to a double figure of a family member, often signifying an impending death. A major shift in Gothic literature occurred in the late  18th and early 19th centuries, where evil was no longer situated within a physical location such as a haunted castle, but expanded to inhabit the mind of characters, often referred to as "the haunted individual." An example of early texts which utilise the Gothic double motif are James Hogg’s "Private Memoirs and Confessions of a Justified Sinner" (1824), Charles Maturin’s "Melmoth the Wanderer" (1820), as well as Robert Louis Stevenson's novella "Strange Case of Dr Jekyll and Mr Hyde" (1886). In the early 20th century, the Gothic double motif expanded to new mediums such as film to  explore an emerging fear of technology replacing humanity. A notable example of this is the German expressionist film "Metropolis" by Fritz Lang (1927), as well as "Invasion of the Body Snatchers" (1956) and "Westworld" (1973). In the 21st century, the Gothic double motif has been used in film and literature to explore gender identities, referred to as the "Trans Gothic" and apparent in the film "The Skin I Live In" (2011) and the novel "Confessions of the Fox" (2020).