The following article has been copied (with the owners permission) from Donald Tyson's Supernatural World Website. I found it a very interesting read, which I though our members would enjoy. The original source can be found at Donald Tyson's Website along with many other facinating subjects.
Do ghosts exist? Of course they do. Why else would tens of thousands of people from all nations around the world and all periods in human history report seeing them under more or less similar circumstances? The question you should be asking yourself is, granted that ghosts exist -- what are they?
The most important thing to know about ghosts is that they are not the souls of dead people returned to communicate with the living. Dead is dead. Unless you believe in the reincarnation of the lower soul with the memories of its past lives intact, there is no coming back (I do not believe in the reincarnation of the personality and memory).
Neither are ghosts physically present when you see them. They are present in the astral world which always overlaps the physical world. You see a ghost when, for various reasons, the separation between the two levels of reality becomes very thin.
From historical accounts, it appears that the perception of ghosts occurs most often at night, in relative or complete darkness, or at least in some shadowed place, usually when the air is still. Certain localities are favorable for the appearance of ghosts -- why is difficult to determine. One theory has it that a ghost is a kind of psychic recording of an event in the past that took place at that locality, and that the locality acts as some sort of recording medium, and periodically replays the event under the right conditions.
Ghosts are often described as shadowy or translucent. Only portions of their body may appear -- a relative of mine once saw a ghostly hand project itself upward through the surface of a school desk that was stored in a dark school basement. Sometimes ghosts walk out of or into walls, or through furniture. They can do this because, to them, our physical reality is no more than a projected three-dimensional image.
There are many exceptions to this general description, of course. Some ghosts appear as real and as solid as a person of flesh and blood. Some appear in full daylight, and are seen by numerous persons at the same time, or on numerous occasions. More rarely they interact with others, talking and even laughing with them, or touching them. However, as a broad rule of thumb, ghosts appear in haunted places, at night when the light is poor, when the air is quiet, to individuals who are frequently (but not always by any means) going to bed or waking from sleep. Usually they do not speak, or take the least notice of their observer. They perform the same set of actions on successive occasions, as though performing a play, or in a trance state, or as though they were themselves projections of a cinema image.
You may ask how a projected astral image can touch you? The answer is a bit difficult to grasp at first consideration, because it challenges your normal concept of reality. You need to realize that what you see in the world around you is being created by your brain from raw sensory data. Your world exists inside your head, even though it appears to exist outside your body. Because your world is really a mental construction, it is possible for an astral being to appear completely solid and real to your perceptions. When this happens, you may find yourself unable to differentiate between a physical object and an astral object, or a physical person and a ghost.
Usually there is a difference between our perception of a physical object and an astral object, which is why ghosts appear incomplete, dim, shadowy, pale, translucent, and so on. My point is, at times there is no difference in perception between the physical and astral realities. This rarely occurs for the average person, but it does occur. Under this circumstance, any entity or thing in the astral realm can interact with you with all the solidity and reality of a physical entity or thing.
If ghosts are merely astral recordings of past events, how do they interact and communicate with human beings? Usually, they don't. When they do take notice of a human observer, it indicates that they are not a pure ghost, but an astral entity that has assumed the physical appearance of a dead person. On rare occasions, it is indeed possible to talk with ghosts, or communicate with them through gestures, but when this happens, the ghost is really a spirit of the astral world in disguise.
Astral spirits can assume different shapes and features more or less at will. They enjoy the company of and interaction with living human beings. When the emotions of a human being are very strong -- for example, just after the death of a loved one -- an astral spirit may put on the body of the departed and appear to his or her lover or family. If you have ever had anyone close to you die, you will probably have experienced extremely vivid dreams in which you are talking with that person. The being in these dreams is not your departed friend or relative, but an astral spirit. Such spirits can appear both in dreams and in our waking reality when the proper conditions exist.
Are ghosts dangerous? Usually not. In their most common manifestation they are merely shadows or images without physical substance. On the other hand, if an astral spirit decides to haunt an individual person rather than a particular place, they can become very distracting. This is especially true if the pseudo-ghost takes on physical substance and is able to touch the person being haunted.
The touch of a ghost is chilly. It draws heat from the surface of the body, and if it persists, this cold gradually penetrates into the muscle and fat. I have had the experience of being embraced for prolonged periods of time by ghostly spirits. It takes a little getting used to. I enjoy it most on hot summer nights. In the wintertime, it makes me shiver and put another blanket on the bed. These astral ghosts are lonely beings, and they like to sleep in the beds of those who do not reject them, in the same way stray dogs or cats like to rub up against friendly persons.
I should mention here that animals sometimes appear as ghosts. One night while lying in bed I had a litter of drowned kittens snuggle up under my armpit for warmth and go to sleep. I didn't mind, although their attempts to suckle on my armpit tickled like crazy! The poor things still had their eyes closed, they were so young. Their fur was wet, which is how I knew they had been drowned.
From personal experience, many times repeated, I can state categorically that the touch of such a spirit may feel complete physical. At these times there is no way to differentiate the hand of a ghost laid on your shoulder from the hand of a person, except that the ghost's hand will (usually) be somewhat cool.
I have had so many interactions with spirits over the years, they do not trouble me in the least, but I can understand how being touched by a ghost in the darkness, alone in bed, might startle, or even frighten, some individuals. If this happens to you, relax. You are very unlikely to be harmed, since most spirits mean no harm. If you are really troubled, turn on a light or get up from your bed or chair and walk into another room. This should dispel the astral presence.
The most important thing I can say about ghosts is, never mistake a ghost for the human being it resembles. Not even if the ghost talks to you, and declares itself to be the departed human being. Astral spirits who imitate dead people are seeking attention and love. If you wish to give them this love (as I often do), fine; but if you do not wish to be deceived and bothered by them, turn your mind away from them and focus it firmly on some other task, such as reading a book or washing your hair. They may persist for a time, but eventually they will give up in disappointment and go away.