"In archaic societies where shamanism is a thriving institution, the signs are fairly easy to recognize: oddness or uniqueness in an individual. Epilepsy is often a signature in preliterate societies, or survival of an unusual ordeal in an unexpected way. For instance, people who are struck by lightning and live are thought to make excellent shamans. People who nearly die of a disease and fight their way back to health after weeks and weeks in an indeterminate zone are thought to have strength and soul. Among aspiring shamans there must be some sign of inner strength or a hypersensitivity to trance states. In traveling around the world and dealing with shamans, I find the distinguishing characteristic is an extraordinary centeredness. Usually the shaman is an intellectual and is alienated from society. A good shaman sees exactly who you are and says, "Ah, here's somebody to have a conversation with." The anthropological literature always presents shamans as embedded in a tradition, but once one gets to know them they are always very sophisticated about what they are doing. They are the true phenomenologists of this world; they know plant chemistry, yet they call these energy fields "spirits." We hear the word "spirits" through a series of narrowing declensions of meaning that are worse almost than not understanding. Shamans speak of "spirit" the way a quantum physicist might speak of "charm"; it is a technical gloss for a very complicated concept."