Carl Sagan, a lifelong skeptic of paranormal claims, in his last book (1996) identified Stevenson’s research as one of three areas of potential significance (the others were psi tests with random number generators and under mild sensory deprivation, i.e., the ganzfeld).
Stevenson was drawn to extrasensory communications and phenomena suggestive of survival and reincarnation because, if these processes could be established, they would demonstrate that human beings were more than their physical bodies. Stevenson came to concentrate on reincarnation because he saw that it posed an especially keen challenge to materialistic assumptions. It also had clear implications for medicine. Reincarnation might help to explain, among other things, the origins of individual differences and why a given person developed a given disease, one of the “leitmotif” questions of his career.