Dr. Ian Stevenson is the former head of the Department of Psychiatry at the University of Virginia, and now is director of that school's Division of Personality. In the more than 40 years that he has devoted to the documentation of past-life memories, Stevenson has done a great deal to put a serious study of reincarnation on a scientific basis. His classic work,Twenty Cases Suggestive of Reincarnation, which was published by the American Society for Psychical Research in 1966, is an exhaustive exercise in research in which Stevenson dons the mantle of historian, lawyer, and psychiatrist to gather evidence from as many percipients as possible.
Stevenson has now collected over 3,000 cases of past-life memories of children from all over the world, and in 1997 published Reincarnation and Biology: A Contribution to the Etiology of Birthmarks and Birth Defects. In the first volume of this massive work, he primarily describes the various kinds of birthmarks, those uniquely distinguishing marks on a newborn's skin cannot be explained only by inheritance. The second volume focuses on deformities and other anomalous markings with which certain children are born and cannot be traced back to inheritance, prenatal, or perinatal (formed during birth) occurrences.
Although Stevenson concedes that nobody has "as yet thought up a way that reincarnation could be proved in a laboratory test tube," he argues that even in the laboratory the scientist cannot escape from human testimony of one kind or another. In his essay "The Evidence for Survival from Claimed Memories of Former Incarnations," which won the American Society for Psychical Research's 1960 contest in honor of William James (1842–1910), Stevenson discussed a number of hypotheses that he feels deserve consideration in attempting to comprehend data from cases suggestive of reincarnation. Among these hypotheses are the following:
Unconscious Fraud. In some cases, other individuals have attributed statements to the subjects alleging past lives that they never made, and in this way have permitted the initial claim to grow out of proportion. Stevenson terms this a kind of "collective hallucination" in which further statements are imaginatively attributed to the subjects.
Derivation of the "Memories" through Normal Means with Subsequent Forgetting of the Source. Stevenson holds this hypothesis to be most often responsible for the many cases of pseudo-reincarnation. He quotes from the work of E. S. Zolik, who studied the ability of students to create fictitious former lives while under hypnosis. These fantasy personalities were the products of bits and pieces of characters in novels, motion pictures, and remembered childhood acquaintances. Because of the remarkable ability of the human mind to acquire paranormal information and to create fantasy personalities all its own, Stevenson cites another difficulty in serious research into cases suggestive of reincarnation: "We need to remember that items normally acquired can become mingled with those paranormally derived in the productions of persons apparently remembering past lives."
Racial Memory. Stevenson, a medical doctor as well as a psychiatrist, is well aware that science has not yet discovered the parameters of genetic transmission. He feels, however, that such a theory applied to the alleged memories of previous lives will encounter serious obstacles. While he concedes that the hypothesis of "remembering" our ancestors' lives might apply in those instances where it can be shown that the subject having the past-life memories belongs to a genetic line descending from the personality whom he or she claims to be, in most cases, Stevenson believes that the separation of time and place makes "…impossible any transmission of information from the first to the second person along genetic lines."
Extrasensory Perception of the Items of the Apparent Recollections in the Minds of Living Persons. Stevenson finds it difficult to accept the theory that an individual gifted with paranormal talents should limit the exercise of such abilities only to communication with the specific living persons who might have relevant bits of information about the deceased personalities from whom the subjects claim to derive their memories.
Retrocognition. Stevenson is receptive to the notion that the psychic ability known as retrocognition could be responsible for some cases suggestive of reincarnation. The subjects in such cases could be stimulated by being at the scene of historical events, by some object connected with the events themselves or persons who participated in them, or in an altered state of consciousness, such as staring at a crystal ball or being in a trance.
Possession. The doctor recognizes the plausibility of temporary possession as an explanation for some apparent memories of former incarnations. But he makes a very important distinction: In cases of possession, the entity that has accomplished the transformation of personality usually does so solely for the purpose of communication with its loved ones on the physical plane, and it never claims to be a former incarnation of the subject who has temporarily provided a physical body. In true cases suggestive of reincarnation, there is no other personality claiming to occupy the body of the subject and the entity speaks of a former life, not of communication with surviving loved ones.