The Spirits' Book
Book Three - Moral Laws
Chapter IV - III. Law of Reproduction
Succession and Development of the Human Race
689. Are the human beings currently living on Earth a new creation or the improved descendants of prehistoric human beings?
“They are the same spirits that have come back to improve themselves in new bodies, but who are still very far from reaching perfection. The current human race that is slowly invading the Earth, and replacing preexisting humans, will one day decline in number and disappear. It will be replaced by other, more perfect races that will be descendants of the present race, as civilized men and women today are derived from the wild savages of prehistoric times.”