There is a theme woven through the shamanisms of the Upper Amazon — that human beings in general, and shamans in particular, have powerful urges to harm other humans. The difference between a healer and a sorcerer is that the former is able to bring these urges under control, while the latter either cannot or does not want to.

Thus, what distinguishes a healer from a sorcerer is self-control. This self-control must be exercised specifically in two areas — first, in keeping to la dieta, the restricted diet; and, second, in resisting the urge to use the magical darts acquired at initiation for frivolous or selfish purposes. Shamans who master their desires may use their powers to heal; those who give in to desire, by their lack of self-control, become sorcerers, followers of the easy path.

As simple as the restricted diet seems, it is hard to keep. Food without salt or sugar is bland and boring; I have tried to live on just fish and plantains, and, believe me, the craving for salt or sugar can become intense. Commenting on a similar diet among Achuar apprentice shamans, limited to plantains, boiled palm hearts, and small fish, anthropologist Philippe Descola calls it “dauntingly dull.” In order to be a shaman, one Napo Runa elder says, “one has to suffer much with all this fasting.” Thus, la dieta is a form of self-imposed discipline, which makes the apprentice or shaman worthy of the love of the plants.

Secoya shaman Fernando Payaguaje, speaking of the restricted diet kept when drinking yagé, says: “Some people drink yagé only to the point of reaching the power to practice witchcraft; with these crafts they can kill people. A much greater effort and consumption of yagé is required to reach the highest level, where one gains access to the visions and power of healing. To become a sorcerer is easy and fast.” As anthropologist Françoise Barbira Freedman puts it, shamans who master their emotions and aggressive desires use their powers to heal; apprentices who break the rules of their ascetic training become weak, and therefore become sorcerers.

Similarly, a significant part of the initiation process is for the new shaman to demonstrate the self-control which separates healers from sorcerers. Self-control is manifested in resisting the immediate urge to use newly acquired powers to cause harm. Among the Shuar, there is a general sentiment among the people that becoming a shaman — acquiring tsentsak, magic darts — creates an irresistible desire to do harm, that “the tsentsak make you do bad things.” Shuar shamans themselves dispute this. While the tsentsak indeed tempt one to harm, the desire can be resisted; those who “study with the aim to cure” become healers.

Shuar shaman Alejandro Tsakímp describes one of these temptations as the urge to try out the new darts on an animal — “a dog or a bird, anything that has blood.” Once one does that, once one “starts doing harm, killing animals, one cannot cure,” but becomes a maliciador, a sorcerer. Similarly, the Desana believe that sorcery is very dangerous, apt to rebound on its practitioner, and to be used only in narrowly defined circumstances — for revenge on a sorcerer who has killed a family member, for example. Thus it is the novice, the inexperienced, the untrained person who causes sickness — who lacks the self-control imposed by the shamanic initiation, who experiments with evil spells, who uses them carelessly and irresponsibly, just to see if they work.

This self-control is often expressed in terms of regurgitation and reingestion of shamanic power. Anong the Shuar, after a month of apprenticeship, a tsentsak comes out of the apprentice’s mouth. The apprentice must resist the temptation to use this dart to harm his enemies; in order to become a healing shaman, the apprentice must swallow what he himself has regurgitated. Among the Canelos Quichua, the master coughs up spirit helpers in the form of darts, which the apprentice swallows; here, too, the darts come out of the apprentice’s body and tempt him to use them against his enemies; again, the apprentice must avoid the temptation and reswallow the darts, for only in this way can he become a healer.

This self-control is sometimes also put in terms of turning down gifts from the spirits. The spirits of the plants may offer the apprentice great powers and gifts that can cause harm. If the apprentice is weak and accepts them, he will become a sorcerer. Such gifts might include phlegm which is red, or bones, or thorns, or razor blades. Only later will the spirits present the apprentice with other and greater gifts — the gifts of healing and of love magic.

Self-control is thus central. It is difficult to control lust and abstain from sorcery; even experienced shamans must work hard to maintain control over their powers, which are often conceptualized as having their own volitions.The pathogenic objects that are kept within the shaman’s body, often embedded in some phlegm- or saliva-like substance, are also in some sense autonomous, alive, spirits, sometimes with their own needs and desires, including a need for nourishment, often supplied by tobacco. If not fed properly, they can turn on their possessor, or seek their food elsewhere.

The magic darts kept within the chest of a Shuar shaman, for example, are living spirits, who can control the actions of a shaman who does not have sufficient self-control. The magic darts want to kill, and it requires hard work to keep them under control and use them for healing rather than attack. Similarly, the Parakanã of Eastern Amazonia believe that shamans possess pathogenic agents that cause sickness, called karowara. When animated by a shaman, karowara are tiny pointed objects; inside the victim’s body, they take the concrete form of monkey teeth, some species of beetle, stingray stings, and sharp-pointed bones. Karowara have no independent volition; but they have a compulsion to eat human flesh.

In this way, the pathogenic objects hidden within the shaman’s body enact the Amazonian belief in innate human aggressiveness. To be a healer is to keep this powerful force in check by great effort.