The German word, “doppelganger”, translates as (doppel) double, and (gänger) goer or the ghostly double of a living person. Today, the word is loosely used to describe any look-alike person, but in its true form it refers to the sensation of glimpsing oneself in peripheral vision where there is no mirror or reflective surface. Generally believed to be harbingers of bad luck, if a doppelganger is seen by one's relative or friend it is said to portend illness or danger, whereas, if seen by oneself it means immanent death. The Norse, “vardøger”, is the double of a living person seen to be performing ones tasks in advance; somewhat like déjà vu in reverse.

One famous individual who claimed to have seen his doppelganger was Percy Bysshe Shelley, English poet and husband of author Mary Shelley. Less than a month before his death by drowning, Percy Shelley apparently related to his wife that he had met himself on the terrace and that his double had even spoken to him, asking him, “How long do you mean to be content?”

Abraham Lincoln purportedly experienced an apparition of himself on the evening of his election to the presidency. Weary from the campaign, he threw himself down upon a sofa. Across the room, he saw a full length vision of himself but with two faces, one face deathly pale. When he informed his wife of the vision, she came to the conclusion that the meaning was that he would be elected to serve two terms but would not live through the second.

The author and poet, Johann Wolfgang von Geothe, related a doppelganger experience in his autobiography. He was leaving the home of his lover after saying goodbye forever when he perceived his double riding toward him in unfamiliar clothing. Eight years later, on that same road he suddenly realized that he was wearing the same clothing of his earlier vision.