From the guys over at Triablogue:
Some cable TV channels are running shows on apparitions and hauntings. Needless to say, that’s not the most reliable source of information. To put this in proper perspective, I’ll be quoting some excerpts from an old book by John Warwick Montgomery:
Everyone enjoys a good ghost story. But are ghosts “real”? And if they are, what are they and how is their reality to be correlated with established biblical teaching? What is to be said for the spiritualist movement in its endeavor to establish contact with those who have passed to the other side?
Ghosts are most definitely real. At least, some ghosts are…Facts are relatively easy; it is the interpretation of them that is often hard! When faced by such data as those just presented [137-40], many persons simply refuse to accept them because they think that the interpretations will destroy their faith (in non-Christian materialism; in Christian judgment after death; etc). Some viewpoints–such as materialism–are indeed in tension with spectral evidence; but others–including orthodoxy Christianity–are certainly not. Consider the following multi-level explanatory scheme.
1.Ghosts as telepathic hallucinations arising from the minds of the living…however, it hardly seems to be able to account for the powerfully objective focus of so many ghost accounts, particularly when more than one person sees the ghost at the same time, or independently at different times.
2.Ghosts as telepathic hallucinations arising from the minds (brains) of the dead…MacLellan’s theory, by its shift of emphasis from the living to the dead, handles problems not covered in 1., but it fails in those cases where the specter represents a person whose brain has been cremated (death by fire) or totally destroyed in some other way.
3.Ghosts as residual human aura. The aura is a radiating luminous envelope or cloud projected from and surrounding the body. It is sometimes referred to as the “subtle body” or “etheric body” or (when separated from its body) the “human double.” A tremendous literature exists on this subject…Most ghostly apparitions involve suicide, passion, violent death, or high emotional tension of some kind; perhaps extraordinary emotion is the trigger that releases the aura to “haunt” for a time the places familiar to the deceased person–and especially those places connected with the emotional trauma. Ghosts generally represent recently–or fairly recently–deceased persons. Since the aura gradually fades away after death, this would serve to explain why few ghosts of Roman soldiers are reported these days! If the more violent the death-trauma or emotional level of the decedent, the longer the “life” of his aura, then castle ghosts could be accounted for, since the stories associated with them almost always involve hideous events of one kind or another. Note that the aura is not the person; thus this explanation says nothing whatever against the immediate arrival of the deceased person at his appropriate eternal habitation, even while his aura continues for a time to walk the earth.
4.Ghosts as the dead themselves, on their way to the reward determined once for all by their relationship or lack of relationship with Christ on earth, but not yet entered fully into that reward…no postponement or possible reversal of the judgment at death is suggested. Only the time-lag between death and heaven, or death and hell, is extended to account for ghostly phenomena that show more self-direction than the “human aura” would allow for, and yet to not engage in either angelic or in demonic missions for the living.
5.Ghost as the damned sent back to haunt the living or as Satanic counterfeits of the dead.
6.Ghosts as the saved sent back to earth by God for a special mission. Elijah and Moses on the Mount of Transfiguration seem to be clear instances of this phenomenon (cf. particularly Mt 17:3,8).
These six explanatory levels offer the tools for dealing with most attested spectral phenomena. Sometimes one interpretation will best fit the data, sometimes another.
Principalities and Powers (Bethany 1973), 136-43.