In parapsychology, an apparitional experience is an anomalous, quasi-perceptual experience. It is characterized by the apparent perception of either a living being or an inanimate object without there being any material stimulus for such a perception. The person experiencing the apparition is awake, excluding dream visions from consideration.
In scientific or academic discussion, the term "apparitional experience" is to be preferred to the term "ghost" in respect of the following points:
Attempts to apply modern scientific or investigative standards to the study of apparitional experiences began with the work of Edmund Gurney, Frederic W. H. Myers and Frank Podmore, who were leading figures in the early years of the Society for Psychical Research (founded in 1882). Their motive, as with most of the early work of the Society, was to provide evidence for human survival after death. For this reason they had a particular interest in what are known as ‘crisis cases’. These are cases in which a person has a quasi-perceptual experience of someone at a distance at the time of that person’s death or other crisis. If the temporal coincidence of the crisis and the distant apparitional experience cannot be explained by any conventional means, then the presumption is made that some as yet unknown form of communication, such as telepathy (a term coined by Myers) has taken place.
While the extent to which the work of Gurney and his colleagues succeeded in providing evidence for either telepathy or survival of death is still controversial, the large collection of firsthand written accounts which resulted from their painstaking methods still constitutes a body of valuable data concerning the phenomenology of hallucinations in the sane.
A notable later discussion of apparitional experiences was that of G. N. M. Tyrrell, also a leading member of the Society for Psychical Research of his day. Tyrrell accepted the hallucinatory character of the experience, pointing out that it is virtually unknown for firsthand accounts to claim that apparitional figures leave any of the normal physical effects, such as footprints in snow, that one would expect of a real person. However, Tyrrell develops the idea that the apparition may be a way for the unconscious part of the mind to bring to consciousness information that has been paranormally acquired – in crisis cases, for example. He introduces an evocative metaphor of a mental ‘stage-carpenter’, behind the scenes in the unconscious part of the mind, and constructing the quasi-perceptual experience that eventually appears on the stage of consciousness, so that it embodies paranormal information in a symbolic way, a person drowning at a distance appearing soaked in water, for example.