osis and haraldsson's definition of hallucinations

   In 1977, the parapsychologists Karlis Osis (19171997) and Erlendur Haraldsson (b. 1931) defined hallucinations as follows: "Hallucinations are a form of mental imagery involving sensory qualities similar but not corresponding to sensory input (which is the normal basis of perceptual imagery)... That which singles out hallucinations from all other kinds of imagery is the fact that the person is awake during them and experiences the same sensation of realness regarding the image as he or she does when perceiving real objects... Therefore, it might be said that a hallucination is imagery coupled with a misapplied sense ofreal-ness. However, a sense of realness in ESP-based hallucinations is appropriate because of their correspondence with a kind of external reality that is not within reach of the perceptual organs."

   References

   Osis, K., Haraldsson, E. (1977). At the hour of death. New York, NY: Avon Books.