An introduction to parapsychology

Irwin begins by defining parapsychology as the investigation of ostensibly paranormal experiences, some of which may ultimately prove to have an explanation in terms of conventional scientific principles. He sees parapsychological investigations as being restricted to three primary domains of content, comprised of extrasensory perception (ESP), psychokinesis (PK), and the survival of death; and he notes that certain other forms of experience (such as Bigfoot and UFO encounters) that are sometimes classified as paranormal by some writers would fall outside the traditional scope of parapsychology. He maintains that the study of parapsychological experiences (i.e., experiences that seem to involve the operation of psi, or are suggestive of survival) is of value whether or not such experiences ultimately prove to have a basis in the operation of paranormal principles.