Dr. Todd Murphy, a neuroscientist who studies near death experiences (NDEs), has come up with an interesting theory regarding reincarnation. He thinks it developed for the same reason that any other trait establishes itself in a population - namely, because it gives a reproductive advantage to those involved.
Furthermore, Murphy noted that many of the features found in NDEs vary from culture to culture. He suggests that people who make progress from one lifetime to another are those who have learned to accumulate merit in accordance with the values of their own clan, tribe, or nation. In short, they have learned to play by the rules laid down by their society. These rules will differ from group to group, hence the variations between cultures.
When they are reborn, these people will tend to rise to higher rank - because they have learned the social skills valued by their group. These skills make it more likely that they will rise to a high status. People with higher status have historically had more offspring, so the society benefits by having more people of character and competence. At the same time, this whole procedure reinforces the values of the culture.
This cultural approach is consistent with our own belief that rebirth normally occurs within the family or clan - a belief also held by other groups, to include the Tlingit Indians.
Murphy, as a scientist, does not go so far as to say that reincarnation is an actual fact. All he will definitely state is that “information which enables individuals to adapt is conserved at death, and passed on to other individuals still undergoing prenatal development elsewhere. To say that anything more than information is reborn would involve making assumptions for which there is no evidence.”
The transmission of this “information which enables people to adapt” sounds a lot like Edred Thorsson’s assertion that only certain soul components - the hamingja-fylgja complex - are transferred from one person to another. Edred sees the “I” or ek going to the abodes of the Gods or to Hel, where it awaits eventual rebirth.
My own thought is that more spiritually advanced individuals have more options after death. Those who did not evolve, who were satisfied with the unchallenged life and who made no effort to develop will and consciousness, will find an afterlife that is little more than a vegetative state. Those who forced themselves to grow, I believe, have the option of an actual rebirth of the ek, or continued existence in the halls of the Gods, or some combination of these as determined by their will. More power equals more freedom, in the afterlife just as here in Midgard.
What can we take away from all this speculation? Evolving might and consciousness is good. The powers thus gained will, sooner or later, be reinvested in the group for its benefit.
Dr. Murphy’s relevant article can be found at http://www.shaktitechnology.com/rebirth.htm