A doppelganger is German for double walker and is a copy of yourself that also inhabits existence at the same time. Whether the double of yourself is a clone, or version of you from some other point in time is debatable. The doppelganger is usually a bad omen for one who witnesses or see's their doppelganger.
There are, however, some interesting stories of doppelgangers, and in Egyptian mythology the doppelganger, called a "Ka", was believed to be Helen who was involved in misleading Paris of Troy, ultimately aiding the end of the war to a significant degree. In Norse mythology a "vardoger" is the term used for doppelganger and is believed to be seen doing things you will do, before you do them, kind of acting as a mirror into your future. In Breton, Cornish and Norman French folklore the doppelganger is also seen to be an omen of death and not anything positive.
Though doppelgangers have been used in the past to theorize, discuss and analyze the duality of the human condition and nature, its symbolic analogies might be more than just analogies. There are quite a few famous accounts of one seeing their doppelganger. One is of John Donne, an English poet who saw his wife's doppelganger in Paris in 1612, surprisingly enough on the same night as the stillbirth of the daughter he was to have. Percy Shelley, another poet who drowned in Italy had a wife named Mary who was an author and had said that Percy met his own doppelganger a week after his wife's miscarriage which was almost fatal. Percy discussed visions he had around that time and spoke of a discussion he had with his doppelganger which said to him "How long do you mean to be content"? Was this some introspective concern for Percy that his doppelganger had? Johann Wolfgang Von Goethe wrote as is mentioned in his autobiography, "Those were painful days… I now rode along the foot-path toward Drusenheim, and here one of the most singular forebodings took possession of me. I saw, not with the eyes of the body, but with those of the mind, my own figure coming toward me, on horseback, and on the same road, attired in a dress which I had never worn, — it was pike-gray [hecht-grau], with somewhat of gold. As soon as I shook myself out of this dream, the figure had entirely disappeared. It is strange, however, that, eight years afterward, I found myself on the very road, to pay one more visit to Frederica, in the dress of which I had dreamed, and which I wore, not from choice, but by accident". This is a strange account and another case where details involving the account seemed to predict future outcomes or details.
In Irish folklore they call the doppelganger a fetch and some think that if the doppelganger is seen in the morning instead of the evening it is a good sign signifying long life. If seen in the evening it is not a good omen and can have the significance of a looming death again. It is mentioned in researching doppelgangers that a theory exists, that one is capable of, accidentally or purposefully, in essence, emitting or projecting their selves to remote and distant places, having the ability to be able to communicate and function just as if the person physically traveled to the location. This is also known as bilocation.
Another interesting case of a doppelganger is Emilie Sagee a teacher who, in 1845 would reportedly appear and disappear in class in front of students. One day while writing at the chalkboard in class, her doppelganger appeared or seemed to materialize right next to her and copy everything she did or wrote, as if you might see in the reflection of a mirror. This happened in front of 13 students and the only thing that was noticeably different about the doppelganger is that it didn't have any chalk in its hand as it appeared to write. Another similar situation was reported during dinner time when the doppelganger materialized again, standing right behind Emilie and mimicked every move in the same manner, but held no utensils in her hands. This wasn't always the case though as her doppelganger was seen again in different parts of the school, doing different things such as attending to gardening. While the teacher was gone from her chair once, the doppelganger appeared in her place and some children approached it and discuss feeling an air of resistance. One actually passed through the doppelganger and it slowly vanished shortly afterward. Although Emilie never actually saw the doppelganger herself, she noticed that she felt drained and exhausted after it was reported to have been seen and even looked pale during the times it was seen.
Guy De Maupassant, a novelist of French origins said that he was haunted by his doppelganger around the end of his life and also states that his doppelganger would speak what was being wrote by the real Guy as he wrote it. Even Abraham Lincoln had an encounter with his own doppelganger and according to the story Abe goes on to say "Opposite where I lay was a bureau with a swinging glass upon it and looking in that glass I saw myself reflected nearly at full length; but my face, I noticed had two separate and distinct images, the tip of the nose of one being about three inches from the tip of the other. I was a little bothered, perhaps startled, and got up and looked in the glass, but the illusion vanished". Catherine the great, Empress of Russia claims to have seen her doppelganger sitting on her throne and ordered her guards to shoot at it. Shortly afterward she died. Is there something to seeing a doppelganger actually leading to one's untimely death? Queen Elizabeth I died shortly after claiming to have seen her doppelganger as well!
There are other stories of people seeing their doppelganger or someone who is eerily the same in appearance to their self, or someone that they know, and the story goes on. It makes one wonder, to what extent could the perceived incident of viewing a doppelganger be that of an apparition, or vision? Maybe seeing a doppelganger can be connected to a mental illness such as some have proposed. Suppose you are seeing a higher version of self being manifested because an important message is to be portrayed, or perhaps, truly a future version of the self? Is the doppelganger an evil spirit that takes a human form as believed by some? Some have mentioned that there are old beliefs that doppelgangers are created by trolls who kidnap and replace the victim with their double. People even have claimed to have been blamed for things their doppelganger has done in the presence of other friends. Can you imagine having a friend or colleague come up to you one day upset for something you haven't done, but claiming that you did do, and that they witnessed you do it?
A study has been done by Shahar Arzy in Geneva Switzerland that is interesting to note. In the research and experimentation it was found that a doppelganger like effect can be produced by using electromagnetic stimulation. Patients would lie in bed and then be given the electromagnetic stimulation to the Temporo-parietal junction and from such, describe feeling the presence of another person. The only problem here is that feeling someone around and seeing them are two entirely different experiences and this gives no credibility to the multiple witnesses of doppelganger sightings.
Bilocation, death omens, future self? Maybe someday we'll have enough data to know for sure but I don't think it should be entirely ruled out as nonsense as more and more people honestly claim to see their doppelganger, not just someone that looks like them. Want more cases? Read 42 personal experiences with doppelgangers here.