One of the most common questions I'm asked when doing interviews for my book, The Case for Ghosts, is what, exactly, a ghost is. While this would appear at first glance to be a fairly simple question—after all, everybody knows what a ghost is, right?—it actually turns out to be a very good—and important—one to ask.

The fact is we often don't know what is meant by the term "ghost." There are many things we call ghosts which are not true ghosts at all: residual entities, for example, are not really ghosts, nor are most poltergeists. Even some interactive spirits are often not ghosts: spirit guides, for example, and those entities we refer to as angels and demons, along with a whole host of other non-corporeal beings, are also not ghosts, further muddying the paranormal waters and demonstrating the need to more precisely define the term "ghost" if we are to ever understand the things. http://www.llewellyn.com

So what is a ghost and, further, what distinguishes them from those other manifestations of the paranormal realm? In other words, what are the main characteristics that define a "true ghost?" While this is a subject still open to debate, my research demonstrates that there are three classic elements unique to ghosts which make them distinct and markedly different from their supernatural cousins. There may be more, of course, but these are the three that stand out the most to me.

The first of these—and perhaps the most important—is that ghosts are always human. To put it more precisely, a ghost is the disembodied conscious energy—that which we might call the personality—of a once living person, as opposed to spirit guides, angels, and other supernatural entities (in my book I refer to such beings as extra-celestials) which have never been human nor have ever existed in a physical state. This distinction is important, for it is in the nature of an entity that we might perceive its purpose and determine what it can and cannot do within the world of linear time and space.

The second characteristic of a true ghost is that it is interactive, at least to some degree—that is, it has the ability to manipulate matter, observe and be observed, and have some capacity to communicate with the living. Of course, among the examples I presented a moment ago—residual entities, poltergeists, and spirit guides—there sometimes is a degree of interaction (especially by poltergeists—making at least some of them potentially ghosts), but for the most part such apparitions are at best manifestations of conscious energy and not ghosts in their own right. Just as it is true that while all robins are birds, not all birds are robins, the same is true with ghosts; simply because and entity is interactive doesn't make it human, while those entities that appear human but remain non-interactive may be nothing more than a replay of an event recorded by the environment and not conscious energy at all. A true ghost, then, must be both human and interactive, or else it is simply something else.

Finally, the third characteristic unique to ghosts is that they are not a natural part of the spiritual realm, but beings that exist apart from it. In other words, whereas spirit guides and angels and other such denizens of the ethereal realm are a natural extension of the spirit world, ghosts are beings that are unnaturally confined to the physical realm for a variety of reasons, usually having to do with either a free-will decision to stay behind or an unwillingness to completely move on to their next level of existence. In essence, then, depending upon ones point of view, ghosts are either "trapped" or choose to reside in a type of "twilight" state that exists between the spiritual and physical realms, effectively making them residents of neither the physical nor the spiritual realm yet subject to elements of both.

So how can something exist within two mutually incompatible worlds simultaneously and yet remain an element of neither? At first thought, such would appear to be contradictory and, as such, illogical; however, what we are dealing with here is not a contradiction but a paradox in that with ghosts we have beings that can be two things at the same time.

Perhaps this exercise will better illustrate this point: imagine dividing your living room into two halves by drawing a narrow line down the center of it. Now we will call everything that exists on the left side of the line the world of matter—that plane of existence subject to linear time and space that we call the physical realm—and everything on the right side the world of pure spirit—that plane of existence which is subject to neither time nor space, but exists as an eternal now that we call the supernatural realm. What's important to recognize is that while these two realms, despite being so different in nature and function from each other, do share a few things in common. For example, both are populated by conscious energies—some housed within a corporeal form and others existing as pure energy—and each is vital for the other realm to exist. Think of them as two sides of the same coin that serve an important role in permitting the other realm to serve its role: the spiritual realm as the abode of conceptual thought and energy and the physical realm as the world of practical experience and physicality. In a nutshell, the physical realm is where spiritual beings go when they choose to experience things and the spiritual realm is where physical beings go to consider what they have just experienced.

With me so far? Good. Now imagine that there exists within the razor thin line you have just drawn an acclimation zone—a "no man's land," if you will (sort of a paper-thin membrane made of pure energy) that paradoxically both separates and joins the two realms together. Now this narrow strip contains elements of both realms in a sort of workable paradox of time/no time and matter/no matter, which is what makes it possible for a spirit returning to the flesh to acclimate itself to the realm of physicality and a person returning to the spiritual realm a place to adjust to living within the realm of timelessness and pure energy. Picture a type of revolving door at this dividing line that says "birth"; on one side and "death" on the other that our souls are constantly passing through on their journey into and out of physicality and you get the idea.

Now it is within this acclimation zone—this place that exists as neither pure spirit nor pure matter, but maintains elements of both—that ghosts exist or, if you prefer, find themselves trapped. Unfortunately, despite possessing no mass and existing as pure conscious energy, beings trapped within this zone are still subject to and aware of—at least to some degree—the passage of time and space, which effectively gives them spatial dimension—that is, they can only be in one place at a time just like those of us in the physical realm. This is what limits them in terms of how far they may roam and where they can go, which is why hauntings tend to be localized to a particular location. In effect, they have one foot in the spiritual realm and one in the physical, but are incapable of completely interacting with either, making them effectively "stuck" between two worlds.

In contrast, those entities we call spirit guides, angels, and demons—I use these terms only because they are so well known; I do not personally believe that angels and demons exist in the biblical sense, though I do believe there are both benevolent and malevolent energies in existence in the universe which we have mythologized with our religions—do not live in this zone, but move effortlessly between the two worlds, making them capable of experiencing the world of time and space at will without being subjected to or limited by either. (It is widely believed that some physical beings share this ability to move between realms of existence via an out-of-body experience, and that all of us may be capable of doing so while dreaming, demonstrating that the process apparently works both ways. If true, this means that those deceased loved-ones we meet in our dreams are not ghosts, but are full-fledged citizens of the spiritual realm who have successfully crossed over but have decided to communicate with us through the mechanism of dreams, leaving us no reason to be concerned about them being trapped.)

What's important to recognize in all this that being a ghost is not a good position to be in—at least in an immediate sense. We are spiritual beings that exist within the confines of a physical body for a reason; to be trapped between these worlds is to exist in an unnatural state that can be frightening and unpleasant for those caught in it, and positively terrifying for those unaware of what is going on. Of course, New Age teaching tells us that the soul moves immediately into the spiritual realm upon death, an idea the possibility of ghosts—human consciousnesses caught between the two worlds—would seem to challenge. However, there is no contradiction when we understand that what is caught in this transitional no man's land is not the human soul—it effortlessly transcends this zone upon death or birth—but the individual personality that soul has generated. In essence, a ghost is the flotsam of the soul, the individualized ego of a previous incarnation that has essentially detached itself from its resident soul and has been cast adrift in the "twilight zone" between the spiritual and physical realms. That is why it can continue to haunt for decades or even centuries when the soul that generated it has long-since moved on.

So why does this disembodied personality choose to stay and how does it manage to find its way out of this fix? First, it stays for a number of reasons (several of which I have outlined in my book, The Case for Ghosts); it may stay because it is either overly attached to something or someone in the physical realm and refuses to give it or them up; it is too emotionally traumatized by its own death to move on; it may be afraid to move on out of fear of hell or judgment (particularly if it was an especially evil person in life); or it may even be anchored to the physical realm because it still possesses great rage and is unwilling to let go of that anger (much like a drowning man who refuses to let go of the anchor that is dragging him to the bottom.) Some ghosts, however, appear to remain more out of choice: for example, some may be immature personalities who simply enjoy frightening others (mischievous ghosts and possibly some poltergeists often fit this profile) while others could be merely curious about this zone and wish to linger awhile to study it (those that we refer to as "curious ghosts") and still others remain behind because they feel they have some important task to perform before they can go (these are commonly referred to as "mission ghosts"). There are even "comfort ghosts" who remain behind out of concern for those left behind and stay just long enough to find some way to assure their grieving families that all is well and that they have passed over safely. Further, the reason a personality chooses or feels compelled to remain behind has much to do with how long it will remain in that state; mission ghosts, for example, tend to be short term entities who will leave once they have completed their task (or have given up trying to accomplish it) while frightened or possessive ghosts may linger for centuries, unwilling to let go of a world they are no longer a part of. It is all linked to the basic personality traits, proclivities, and tendencies the person possessed during life that will determine how long they stay and, for that matter, even whether they will become a ghost at all.

So how does it move on? Many move on when they are tired of playing the game; some, however, need help, either by sympathetic humans willing to convince the entity of the futility of remaining behind (or, in the case of mission or goodbye ghosts, giving it "permission" to go) or by spiritual entities on the other side whose task it is to show these lost personalities the way out. Just as free-will often determines whether one becomes a ghost in the first place, it also appears that free-will has a hand in determining how long one will remain one. The universe is extremely respectful of our decisions, even if those decisions often result in our experiencing unnecessary anguish and pain (in death just as we frequently do in life). In effect, it really is all up to us, whether we realize it or not.

The good news about all this, however, is that most humans will never become a ghost. Instead, most people will move on to the spiritual realm quickly and naturally, effortlessly transcending the acclimation zone on their way to the other side just as they were designed to do. The other good news is that no one remains a ghost forever; eventually all will work their way through it effectively making a haunting more of a wrong turn than a dead end and demonstrating that the universe is nothing if not compassionate and patient with those souls who seem to need constant reassurance of that fact. In the end, we should realize that there is nothing strange or frightening about the spiritual realm; it is our true home and a place we should anticipate returning to once our work here in the physical realm is complete, for that is from there we can truly begin to appreciate the marvelous complexity and sheer joy of existence.