This is an interesting thread although some of the things mentioned have real scientific answers that deserve consideration rather than just thinking
all of these have strange or paranormal mysteries behind them.
De Ja Vu:
This phenomenon is linked to many of the classic De Ja Vu experiences that a reported 70% of people (in legitimate studies) indicate happen to them at
some point in their life or at regular intervals. These episodes are likely linked to various episodes mentioned, such as "time slippage", where in
fact our minds are simply overlaying memories, thoughts, or forgotten images on top of real-time observations of the eye.
The example being that perhaps you read a book on the Civil War, and have watched the History Channel and seen some episode or reenacted film clips of
a battle. In your "minds eye" you envision a scene while reading a book - the brain logs that away although it is not anything you really have seen,
but the memory is enhanced by having seen on TV something similar. Then you go to a Civil War battlefield and swear that you saw a regiment of Union
clad men walking with muskets in a seemingly lonely or isolated portion of the battlefield.
In this case, memory and creative imagery in the brain is playing tricks on your vision as the brain transmits thought or memory images (that never
really happened but were enhanced by real images you saw on TV) and you end up "thinking" that you actually saw the Union soldiers with your own eyes.
In this case your brain played a trick on the nerves of your eyes, and for all practical purposes your brain picked up the images (or so it thought)
and processed them as though they were seen by your eyes in real time.
De Ja Vu is medically explained in similar form. Basically what happens is the eye percieves the object you think you have seen before and sends a
message to the brain as it normally would, but instead of storing the message in short term memory like it's supposed to, the brain receives the
message, and then intantaneously deletes it (so to speak). Then the next second, the eye is still perceiving the object, and relaying the information
the the brain, who now seems to be re-experiencing this information for the first time. Hence, De Ja Vu. Our brains are particularly susceptible to
this type of misfiring when they are overly fatigued or sleep-deprived as many studies have shown already. Most people in Western society are
actually sleep deprived or stressed, which causes the same reaction.
While there is no way to prove the 19th Century stories of people "fading out" or "vanishing", there is some truth that millions of people do "vanish"
so to speak in that they never come home or seemingly "disappear" from normal life. These cases have many times been explained by 1) kidnappings and
murders never discovered; 2) people running away from their own life and taking on a new name and identity, 3) people wandering off into the
wildnerness and literaly dying there never to be found.
Hope these help explain some legitimate reasons behind some of these phenomena which often times relate to our vision and our brain function - not
weird paranormal circumstances (that do exist but not in all cases).
edit on 5-5-2011 by flight-dynamics because: Misspelled word.