A shaman once commented to me that he believed Westerners did not bury their dead. I asked him why he thought such a preposterous thing, and he responded that behind each of us were scores of what he called the "undead." These were ancestors who had not been properly mourned after their death. This occurs not because we do not care about them, but simply because we do not possess the knowledge of what happens to the soul after death. . . . The irony is that when we do not honor and mourn our ancestors, they continue living through us. They die with a great deal of unresolved business in the world.
— Alberto Villoldo, Shaman, Healer, Sage