from the Introduction: Amazonian Vine of Visions
by Ralph Metzner, Ph.D.

Ayahuasca is an hallucinogenic Amazonian plant concoction, that has been used by native Indian and mestizo shamans in Peru, Colombia and Ecuador for healing and divination for hundreds, perhaps thousands of years. It is known by various names in the different tribes, including caapi, natema, mihi and yajé. The name ayahuasca is from the Quechua language: huasca means "vine" or "liana" and aya means "souls" or "dead people" or "spirits". Thus "vine of the dead", "vine of the souls" or "vine of the spirits" would all be appropriate English translations. It is however slightly misleading as a name, since the vine Banisteriopsis caapi is only one of two essential ingredients in the hallucinogenic brew, the other one being the leafy plant Psychotria viridis, which contain the powerful psychoactive dimethyltryptamine (DMT). It is the DMT, derivatives of which are also present in various other natural hallucinogens, including the magic mushroom of Mexico, that provides visionary experiences and thus access to the realm of spirits and the souls of deceased ancestors. But DMT is not orally active, being metabolized by the stomach enzyme monoamine oxidase (MAO). Certain chemicals in the vine inhibit the action of MAO and are therefore referred to as MAO-inhibitors: -- their presence in the brew makes the psychoactive principle available and allows it to circulate through the bloodstream into the brain, where it  triggers the visionary access to otherworldly realms and beings. The details of this remarkably sophisticated indigenous psychoactive drug-delivery system, and the history of its discovery by science, will be described and explored in this volume.

As a plant-drug or medicine, ayahuasca and its molecular essences is one of a group of similar substances that defy classification: they include psilocybin derived from the Aztec sacred mushroom teonanácatl, mescaline derived from the Mexican and North American cactus peyote, DMT and various chemical relatives derived from South American snuff powders known as epena or cohoba, the infamous LSD derived from the ergot fungus that grows on grains, ibogaine derived from the root of the African Tabernanthe iboga tree... and many others. As plant extracts or synthesized drugs, these substances have been the subject of a large variety of scientific research approaches over the past fifty years, particularly as to their potential applications in psychotherapy and in the expansion of consciousness for the enhancement of creativity and as amplifiers of spiritual exploration. They have been called psychotomimetic ("madness mimicking"), psycholytic ("psyche loosening"), psychedelic ("mind manifesting"), hallucinogenic ("vision inducing") and entheogenic ("connecting to the sacred within"). The different terms reflect the widely differing attitudes and intentions, the varying set and setting with which these substances have been approached. We will be describing the Western scientific psychological and psychiatric approaches to ayahuasca in this book also.

The concepts of shaman and shamanism are not native to South America; they are derived from Siberian cultures. In recent years they have come to be used for any practice of healing and divination that involves the purposive induction of an altered state of consciousness, called the "shamanic journey", in which the shaman enters into "non-ordinary reality" and seeks knowledge and healing power from spirit beings in those worlds. The two most widespread shamanic techniques for entering into this altered state are rhythmic drumming, practiced more in the Northern Hemisphere (Asia, America and Europe) and hallucinogenic plants or fungi, practiced more in the tropics and particularly in Central and South America. Ayahuasca is widely recognized by anthropologists as being probably the most powerful and most widespread shamanic hallucinogen. In the tribal societies where these plants and plant preparations are used, they are regarded as embodiments of conscious intelligent beings that only become visible in special states of consciousness, and that can functions as spiritual teachers and sources of healing power and knowledge. The plants are referred to as "medicines", a term that means more than a drug: something like a healing power or energy that can be associated with a plant, a person, an animal, even a place. They are also referred to as "plant teachers" and there are still extant traditions of many-years long initiations and trainings in the use of these medicines. The use of ayahuasca in the context of Amazonian shamanism is another topic of this book.

Many Western trained physicians and psychologists have acknowledged that these substances can afford access to spiritual or transpersonal dimensions of consciousness, even mystical experiences indistiguishable from classic religious mysticism, whether Eastern or Western. The new term "entheogen" attempts to recognize this element of access to sacred dimensions and states. In the North American peyote church, the African Bwiti cult using iboga, and in several Brazilian churches using ayahuasca, we have seen the development of authentic folk religious movements that incorporate these entheogenic or hallucinogenic plant extracts as sacraments -- developing both syncretic and highly original forms of religious ceremony. The Brazilian ayahuasca-using churches by now have thousands of followers, both in South America and in North America and Europe, and they are growing in numbers and influence. So here we have a substance that has profoundly affected the transformation of individuals, now beginning to bring about something like a cultural transformation movement. These facets of the ayahuasca story will also be explored in this book.

As hundreds, perhaps thousands, of Westerners and Northerners have participated in shamanic practices involving ayahuasca (as well as other medicines and non-drug practices) and joined the ceremonies of the various ayahuasca churches, it has become clear that there is a profound discontinuity in fundamental worldview and values between the Western industrialized world and the beliefs and values of traditional shamanistic societies and practicioners. A powerful resurgence of respectful and reverential attitudes toward the living Earth and all its creatures seems to be a natural consequence of explorations with visionary plant teachers. As such, this revival of entheogenic shamanism can be seen as part of a world-wide response to the degradation of ecosystems and the biosphere -- a response that includes such movements as deep ecology, ecofeminism, bioregionalism, ecopsychology, herbal and natural medicine, organic farming and others. In each of these movements there is a new awareness, or rather a revival of ancient awareness of the organic and spiritual interconnectedness of all life on this planet.

As a psychologist, I have been involved in the field of consciousness studies, including altered states induced by drugs, plants and other means, for over 35 years. In the 1960's I worked at Harvard University with Timothy Leary and Richard Alpert, doing research on the possible therapeutic applications of psychedelic drugs, such as LSD and psilocybin. During the 1970's the focus of my work shifted to the exploration of non-drug methods for the transformation of consciousness, such as are found in Eastern and Western traditions of yoga, meditation and alchemy and new psychotherapeutic methods using deep altered states. During the 1980's I came into contact with the work of Michael Harner and others, who have studied shamanic teachings and practices around the globe, involving non-ordinary states of consciousness induced by drumming, hallucinogenic plants, fasting, wilderness vision questing, sweat-lodge and others. Realizing that there were traditions reaching into pre-historic times of the respectful use of hallucinogens for shamanic purposes, I became much more interested in plants and mushrooms that have a history of such use, rather than the newly discovered powerful drugs, the use of which often involves unknown risks. I have come to see the revival of interest in shamanism and sacred plants as part of the world-wide seeking for a renewal of the spiritual relationship with the natural world.

Over the past two millenia Western civilization has increasingly developed patterns of domination based on the assumption of human superiority. The dominator pattern has involved the gradual desacralization, objectification and exploitation of all non-human nature. Alternative patterns of culture survived however among indigenous peoples, who preserved animistic belief systems and shamanic practices from the most ancient times. The current intense revival of interest in shamanism, including the intentional use of entheogenic plant sacraments, is among the hopeful signs that the split between the sacred and the natural can be healed again.

A recognition of the spiritual essences inherent in nature is basic to the worldview of indigenous peoples, as it was for our own ancestors in pre-industrial societies. In shamanistic societies, people have always devoted considerable attention to cultivating a direct perceptual and spiritual relationship with animals, plants and the Earth itself with all its magnificent diversity of life. Our modern materialist worldview, obsessively focussed on technological progress and on the control and exploitation of what are arrogantly called "natural resources", has become more or less completely dissociated from such a spiritual awareness of nature. This split between human spirituality and nature has some roots in the ancient past of Western culture, but a major source of it was the rise of mechanistic paradigms in science in the 16th and 17th century.

As a result of the conflict between the Christian church and the new experimental science of Newton, Galileo, Descartes and others, a dualistic worldview was created. On the one hand was science, which confined itself to material objects and measurable forces. Anything having to do with purpose, value, morality, subjectivity, psyche or spirit, was the domain of religion, and science stayed out of it. Inner experiences, subtle perceptions and spiritual values were not considered amenable to scientific study, and came therefore to be regarded as inferior forms of reality, -- "merely subjective" as we say. This encouraged a purely mechanistic and myopically detached attitude towards the natural world. Perception of and communication with the spiritual essences and intelligences inherent in nature have regularly been regarded with suspicion, or ridiculed as misguided "enthusiasm" or "mysticism".

This strange coure of events has resulted in a tremendously distorted situation in the modern world, since our own experience, as well as common sense, tells us that the subjective realm of spirit and value is equally as important as the realm of material objects. The revival of animistic, neo-pagan and shamanic beliefs and practices, including the sacramental use of hallucinogenic or entheogenic plants, represent a re-unification of science and spirituality, which have been divorced since the rise of mechanistic science in the 17th century. I believe spiritual values can again become the primary motivation for scientists. It should be obvious that this direction for science would be a lot healthier for all of us and for the planet, than science directed, as it is now primarily, towards generating weaponry or profit.

In this book, we will provide a look at the phenomenon of ayahuasca both from the perspectives of objective natural and social science (botany, chemistry, pharmaology, medicine, anthropology and psychology) and from the point of view of subjective experience -- a realm usually considered not amenable to scientific investigation. To do so requires a new look at the epistemology of consciousness.