Ayahuasca has always been used as a hallucinogenic drink by the shamans of Amazonia to enter a trance, during sacred divination or healing rituals. This extremely ancient practice was already proven in pre-Colombian times.

In the Quechua language, aya means « spirit of the dead » and huasca means « liana ». Many Amazonian tribes know ayahuasca by other names: caapi in Tupi, natem in Jivaro, yajé in Tukano.

Ayahuasca is prepared as a decoction of a mixture of the bark and stems of a vine of the Banisteriopsis genus and rubiaceae of the Psychotria genus.

The psychotropic principle is due to these rubiaceae. Chemically, it is DMT (the alkaloid N,N-dimethyltryptamine), which is generally inactive when ingested orally, as it is degraded by the monoamine oxidases in the digestive tract. But the bark of the Banisteriopsis vine contains powerful inhibitors of these monoamines. The ayahuasca decoction releases the potency of DMT’s effects on the brain through the combination of two distinct substances working synergistically. It took the first shamans some knowledge of the pharmacopoeia.

DMT is highly hallucinogenic. Its chemical structure is close to psilocin and serotonin. It has been shown that the human body can also produce DMT naturally, through the pineal gland.

Shamanism, the first natural religion of mankind and widespread throughout the world, very early on found a link between certain natural substances, hallucinatory visions and the experience of imminent death. It was not until the 1960s that specialists in brain chemistry were able to objectify this link, identify the neurochemical mechanisms and neurotransmitters involved – without, however, answering the most important question.

Is the brain a purely self-centred organ, entirely immersed in its neurochemical microcosm? Or is it open to a back world, a world above, an elsewhere? Is the brain a simple machine operating locally, or is it also an interface, serving as an antenna, a gateway, a link with a higher universe?

From the facts reported above, two interpretations can reasonably be drawn.

The first interpretation is materialistic. Everything is chemical and electrical in the brain, dreams, visions, life, death. The brain, in its complexity, is essentially made up of a tangle of physico-chemical links, referring only to themselves, and produced by a kind of spontaneous generation.

The second interpretation, the one followed by the oldest religions of humanity, including shamanism and Vedism, is that the brain occupies the privileged place as the frontier between nature and the supernatural.

DMT is only a molecule, but it is also a kind of key that opens the door to the supernatural, and above all reveals the continuity and congruence of the links between the plants of the Amazonian forest, the brain cells, and the vision of the divine.

The materialist vision is content to note that the chemistry of the brain, in its complexity, can under certain conditions provoke extreme experiences.

This would be explained by the powerful affinity between certain molecules and neuroreceptors in the brain. Thus it is established that the active principle of Cannabis, THC (tetrahydrocannabinol), has a very high affinity for the CB1 receptor found on the membranes of brain cells (in the hippocampus, associative cortex, cerebellum, basal ganglia), spinal cord, heart, intestines, lungs, uterus and testicles.

But this explanation, all mechanical, does not reveal the link between this neurochemical affinity and the nature of the worlds revealed to the initiates, and also revealed to those who have actually experienced imminent death.

There is a priori no congruence between the experience of orgasmic pleasure, which James Olds showed as early as 1952 that it could be provoked ad libitum by stimulating the septal area of the brain, and the experience of a divine vision, or the certainty of having had a glimpse, however fleeting, of the beyond.

Yet both phenomena can be reduced, according to the materialist approach, to neurochemical mechanisms.

There are many other possible theories as to the origin of the higher phenomena of which the brain is capable, and in particular the appearance of consciousness. In a short, visionary book, the great American psychologist William James proposed a theory of the « transmission » of consciousness, as opposed to the theory of the « production » of consciousness by the brain alone.ⁱ

William James likens the brain to an ‘antenna’ capable of perceiving sources of consciousness located in the beyond. Of course, this option may seem fantastical to materialistic minds. It is today experimentally unprovable. But it is a promising research option, it seems to me. It allows us to draw a line, admittedly imprecise, but productive, between the primary forest, the neural interlacing, the galactic depths, and even between all that precedes them, perhaps explains them, and the whole world of phenomena.

Above all, this research option is not incompatible but, on the contrary, perfectly coherent with the immense fund of experiences, resources, testimonies, accumulated by all the religions of humanity since the origins of human consciousness.

All religions have prided themselves on contemplating the most intimate links of the mind and soul with higher realities. This is, for example, the theory of Zohar, which dates back to the Middle Ages, and which explicitly links the root of the human soul to the « Root of All Roots », that is to say, to the Master of all worlds.

iWilliam James. Human Immortality: Two Supposed Objections to the Doctrine. The Ingersoll Lectures. Cambridege, 1898.“But in the production of consciousness by the brain, the terms are heterogeneous natures altogether; and as far as our understanding goes, it is as great a miracle as if we said, Thought is ‘spontaneously generated,’ or ‘created out of nothing.’ The theory of production is therefore not a jot more simple or credible in itself than any other conceivable theory. It is only a little more popular. All that one need do, therefore, if the ordinary materialist should challenge one to explain how the brain can be an organ for limiting and determining to a certain form a consciousness elsewhere produced, is to retort with a tu quoque, asking him in turn to explain how it can be an organ for producing consciousness out of whole cloth. For polemic purposes, the two theories are thus exactly on a par. But if we consider the theory of transmission in a wider way, we see that it has certain positive superiorities, quite apart from its connection with the immortality question.Just how the process of transmission may be carried on, is indeed unimaginable; but the outer relations, so to speak, of the process, encourage our belief. Consciousness in this process does not have to be generated de novo in a vast number of places. It exists already, behind the scenes, coeval with the world. The transmission-theory not only avoids in this way multiplying miracles, but it puts itself in touch with general idealistic philosophy better than the production-theory does. It should always be reckoned a good thing when science and philosophy thus meet. »