Although the term was used by Freud at the end of the 19th century, the uncanny, or unheimlich, describes a fear of something that is both very familiar and yet provokes fear at the same time. The reason for the fear is unidentifiable.
This theory has been used to explain common themes and plots in gothic literature such as the doppelganger where a character either has a literal double or they have a split personality. This is linked to the Romantic idea of subjectivity, where there is not a single fixed identity but a changing one, with many parts to it. Usually their double is immoral or even evil but is still identifiable as that same person. The doppelganger can be seen in: Dr. Jekyll and Mr. Hyde, The Private Memoirs and Confessions of a Justified Sinner by James Hogg, and several short stories such as: Charlotte Perkins Gilman’s ‘The Yellow Wallpaper’ and Edgar Allen Poe’s ‘William Wilson’.
The idea of a split personality leads to the unreliable narrator as a common motif in gothic literature as their subjectivity is explored. If the characters are portrayed to be mad, can the reader trust anything they say? The idea of subjectivity and narration is also interesting in Dracula where the story is not told from one point of view but from many via letter writing and diary entries.