Biologist and anthropologist César Giraldo H. elaborates on his fascinating theory that the potent Amazonian brew ayahuasca can heighten the perception of microbial activity. The visions of ayahuasca, he argues, offer a partial window onto microscopic entities within the body.

Ayahuasca, yopo, and several other entheogenic substances have been trending for a few years now. Following the steps of anthropologists, Western tourists undertake pilgrimages to the forest, or alternatively Amazonian shamans perform ceremonies in cosmopolitan centers, allowing city dwellers to search for psychedelic enlightenment and spiritual healing through these substances. According to ethnographers, and often to the shamans themselves, through these means they engage with lost souls and powerful master spirits of the forest. According to neuropsychological explanations, these substances hack the brain, inducing altered states of consciousness that allow participants to engage with deeper structures underlying the mind. Some anthropologists question the latter explanation because it imposes a Western scientific understanding that disregards the spirits at the core of these beliefs.

I find both the classical and the neuropsychological interpretations of shamanism to be deeply problematic; both perpetuate the translations and assumptions that Christian missionaries have been fostering since the 16th century. Missionaries introduced notions of souls and spirits with the explicit purpose of evangelizing Indigenous peoples across the Americas. At the same time, they sought to discredit shamans, accusing them of employing brain-altering substances to fool themselves and others into believing in beings that existed only in the realm of delusion. But what if the ayahuasca “trip” did not just short-circuit the brain? What if when you see and hear what some shamans describe as tiny but multitudinous, luminous, and powerful beings, adorned with feathered armbands and headdresses, chanting and dancing to their fierce and joyous songs, you were literally seeing and hearing a mighty forest within your own body? What if the beings in these forests were real, if some of these beings were indeed powerful, even potentially deadly like anacondas and jaguars, like the parasites of syphilis and malaria? These are the questions that emerged through my research and which I explore through my most recent book, Microbes and Other Shamanic Beings.

César Giraldo Herrera’s new book (Palgrave, 2018). Content overview can be found here, and the full book can be purchased here.

During the 16th century, one of the main concerns of Europeans was whether American Indigenous peoples had souls or not. With growing imperial ambitions, but also a Christian ideology, Europeans were embroiled in a conflict of interests. They reckoned that if Indigenous peoples lacked souls, they could be enslaved and their lands seized. However, if they had souls, those souls ought to be saved from eternal damnation and had to be converted to the Christian faith. The Church had major stakes in the debate, not only in terms of the souls to be saved, but also of the tithe, the ten percent tax each “soul” had to pay to ensure its salvation, not to mention the properties the Church was likely to inherit or receive in donation. Nevertheless, being a matter of faith, demonstrating the existence of souls and spirits was tricky if not a complete contradiction in terms.

In practice, things were likely to be the other way around: regardless of how powerful an invader, it is extremely difficult to control a territory without dominating the minds of the people who occupy it. Religion has often served that purpose. Whether a group of peoples did or did not have souls often reflected how successful missionaries were in converting them and making obedient subjects out of them. If missionaries were killed, the peoples that had hosted them lacked souls and, according to Europeans, could be subjected to enslaving raids. If missionaries survived and found ways to translate the spiritual concepts of the gospels, perhaps they could convince them that there was a spiritual being, invisible but omnipresent, omniscient, and omnipotent who would punish their immortal souls for all eternity if they behaved against the laws of the Church and the monarchs.

Fray Ramón Pané, who travelled with Columbus on his second voyage, employed notions of the behiques—shamans of the Antillean islands—to translate Christian terms such as souls and spirits. In the notion of opia he found a translation for the souls of the deceased, even though he described opia as some sort of ancestral beings with a taste for guava fruits and for sneaky sexual encounters at night in the bush. He also translated God as Cemi, clarifying that cemies were the false gods or demonic spirits of the locals. In a paradoxical manner, Pané concluded that Antillean Indigenous peoples had notions of souls and therefore had souls to be saved. Nevertheless, lacking instruction in the “True Faith,” none of them knew what they were talking about and therefore had to be converted into Christianity. In parallel, he also directed great efforts towards combating behiques, accusing them of quackery and witchcraft. Amidst many other things, Pané sought to discredit behiques, claiming they shattered their “brains” with the inebriating substances they used to fool themselves and others into idolatry.

At the root of this accusation lies an explanation of the phenomena experienced by shamans, which is not very distant from the one offered by neuropsychology: psychedelic drugs short-circuit the brain, altering consciousness, implying that whatever is experienced in these circumstances is not real; they are hallucinations or delusions.

Later missionaries followed the same path as Pané; anthropologists trailed closely after. In early missionary accounts, as well as on more recent ethnographies, shamans described souls and spirits, or perhaps more literally “images of being” and “masters of the forest,” as beings that could be perceived under certain circumstances, that had tiny but multitudinous bodies that required specific substances for their nourishment and sustenance. These beings could be poisoned or killed by fever, and they preyed upon one another like animals in the forest. They also reproduced, recognized kin, and acted collectively. Some of these beings took abode in particular parts of the body, in soils, clouds, bodies of water, and artifacts. Some of them affected the environment: the fertility of the soil, dynamics of the sea and the rivers, and the climate. Others protected particular animals and plants, inflicting specific infectious and mental diseases on their predators and on intruders to their “sacred” sites. These beings affected the behavior of their protégés and also fostered their growth. Indeed, none of these characteristics matched Christian notions of spirits, which theologists clearly defined as incorporeal, immaterial, and immortal beings.

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However, I was amazed as I started to realize how many of the characteristics attributed to some of these beings matched current scientific understandings of microbes. Microbes are, well, microscopic and multitudinous. They require specific substances for their nourishment and survival, can be poisoned or attacked by fever, and prey upon one another, constituting intricate ecologies. They also reproduce and proliferate. Moreover, recent developments in microbial ecology demonstrate that many, probably most microorganisms recognize and differentiate members of their same species, even those of their own colony, and act collectively through processes known as quorum sensing. Collective behaviors allow some microbes to affect their environments. Other microbes are adapted to the ecologies of particular parts of particular animals and plants. They play crucial roles fostering or regulating our metabolism, our behavior, and our development. In some instances, however, they are pathogenic, causing infectious diseases. Various Indigenous peoples explicitly identified some of those beings with which shamans dealt as the cause for diseases like syphilis, long before Europeans came to have a theory of germs or contagion.

When I first sketched these parallels to my doctoral supervisor, he quickly replied, “This sounds interesting.” Then he was silent for a moment and said: “Well, there is only one problem with your theory: you are assuming shamans can see microbes, but neither they nor we can see them, now, can we?”

Indeed, almost by definition it would seem as if the microbial world could only be perceived with the aid of modern instruments. I blanked out for a couple of seconds.

I was about to trash the idea when I saw a tiny blurred speckle floating through my field of vision. I turned my head, but the image followed the movement. It was a floater. I recalled someone telling me these were detached fragments of the retina floating in the liquid inside the eye.

“Wait a second. Retinal tissue is microscopic; perhaps we can!” I said.

My supervisor looked perplexed.

I asked for another meeting in a fortnight and left in a hurry to follow the tracks of the history of the phenomena that occur inside the eye, otherwise known as entoptic phenomena.

Entoptics have long aroused curiosity; Plato and Newton mention them. However, it was a Czech physiologist called Jan Evangelista Purkinje who developed the most detailed exploration of these phenomena, setting the basis for their understanding. Purkinje would become a scientific rock star during the 19th century. He invented the microtome, the apparatus to cut thin slices of tissues, allowing their description. He described Purkinje cells in the kidney and Purkinje cells of the hypothalamus in the brain. His name is featured in several pages of anatomical atlases. But long before his rise to stardom, he developed his doctoral research playing with lights on his eyes, and he developed a series of subjective methods to observe the eye from within. He drew several of these phenomena, including the earliest map of the blood vessels of a retina, which is still known as Purkinje’s tree, as well as the white blood cells that flow through these vessels. Several physiologists have since refined his methods and confirmed his observations. How could this be?

Purkinje’s graphical depictions of the swirling geometric visual patterns that result from diffuse flickering light hitting the retina. Photo: ViaLibri.

Well, you see, due to some accidents in the evolution of the eye, the retina has a baffling conformation; the nerves and the blood vessels that feed it with oxygen and nutrients stand before it, directly in the path of the rays of light. It is like having the cables in front of the film or the photosensitive chip of a camera. You get the picture: All these vessels, even the microscopic capillaries and the cells that circulate through them, cast shadows and refractions over the visual cells. You should be seeing all these microscopic images. The illusion, the real hallucination, is that the brain normally dampens these signals and edits them out so that we can see the outside world. Purkinje discovered some tricks to bypass the dampening mechanisms of the brain. However, there are multiple circumstances in which the brain allows you to see what is actually happening inside; e.g., when there are low levels of sugar or oxygen, or high levels in carbon monoxide, or antibiotic or hallucinogenic substances, or systemic infections (to which the retina is highly exposed). In other words, the microscopic world inside your body is within your reach.

How much and what of this infinitesimal world could we actually see with just our eyes? It is clear that we can perceive microscopic objects like white blood cells, which are barely six to 15 micrometres in diameter. However, the resolution of this form of microscopy is limited by the sharpness of the eye; smaller microscopic parasites, and even bacteria or at least their colonies could be detectable to a trained eye. However, based on the acuity of the eye there are no grounds to claim that we can see or even detect smaller objects, like viruses or DNA strands.

Several components in ayahuasca brews and in other shamanic substances foster entoptic vision. Furthermore, shamanic rituals often involve fasting, copious smoking, and sleeplessness, inducing low levels of sugar and oxygen and high levels of carbon dioxide, which are also associated with these experiences. Finally, several shamanic procedures (e.g., the movement of fans and crystals) closely parallel the methods employed by Purkinje and his followers to enhance entoptic perception. All this suggests that shamanic practitioners have refined their capacity to see microbial worlds through entoptic microscopy.

ayahuasca shaman
Desana shaman drawing ayahuasca visions. Photo by Gerardo Reichel-Dolmatoff in 1960s, Putamayo Amazon, Colombia.
ayahuasca brew
The ayahuasca brew is typically made from boiling the vine Banisteriopsis caapi with the shrub Psychotria viridis or other plants rich in similar psychoactive molecules.

As a test of proof to examine whether shamans are honing abilities to see microscopic worlds through the eyes, I wanted to analyze how shamans depict the worlds they visit and the beings with which they interact. I wanted to search in these depictions for features of what is known as the geometry of shadow formation. What is this? I will attempt to describe it. If you have a light source (the pupil), an object in the path of light, and a surface (the layer of visual cells) upon which the object casts its shadows, the size and definition of these shadows will depend on a geometrical relation between the size of the light source and the object, as well as the distance of the object to the light source and the surface. If the light source is small or very distant to the object, and the object is close to the surface, the object will produce two shadows: an umbra in the area where all the light is obstructed, and surrounding it will be a lighter shadow, the penumbra, which is illuminated from the sides of the object. As the distance between the object and the surface increases, the umbra will grow smaller and the penumbra larger, until a certain point where the light from all the sides will illuminate the center of the shadow, forming an even lighter anteumbra. The penumbra and the anteumbra will become blurrier with increasing distance from the object to the surface. These are features that characterize entoptic images and distinguish them from neurogenic images, those generated by “short-circuits” of the brain. If these features were found in shamanic art it would be evidence that this art is at least partially based in a form of entoptic microscopy.

Several shamanic traditions are associated with rich artistic traditions, many of which exhibit features that could be explained through the geometry of shadow formation, such as Kuna molas, or Huichol craftsmanship. However, the materials in which many of these artworks are produced restrict the degree of detail and limit the reach of the analysis. On the other hand, there is also abundant ayahuasca artwork that is highly detailed, densely elaborating its symbolism, which also limits a geometrical analysis. Finally, I came across the work of the Ingano artist Carlos Jacanamijoy, son of a very renowned shaman, who develops highly detailed and evocative images of his explorations of ayahuasca. Analyzing his paintings, I found a series of motifs that could be found in different sizes, exhibiting the changes in the size and definition of their forms that could be expected of entoptic images. These motifs can also be found in other ayahuasca and shamanic artworks. Retracing some of these images, I managed to identify white blood cells, displaying characteristic changes of shape, which occur as they flow through capillaries. To me, this was compelling evidence indicating that entoptic microscopy is part of what shamanic visions are about.

I am not arguing that entoptic microscopy is all there is to shamanic or ayahuasca visions. As is evidenced by these experiences and by the high degree of symbolic elaboration in artistic expressions associated with them, clearly there is much more. But what if instead of assuming that shamans are using hallucinogenic substances to short-circuit their brain, fooling themselves and others into believing in things that are not there, as friars since Columbus have argued, we take into account the perceptual capacities with which we are all endowed, and explore what we could come up to see, some of the worlds that may be behind that rich symbolism. It might be more than visions. Due to similar issues in the conformation of the cochlea in our inner ears, we should be hearing the cells circulating through them, and indeed sometimes we can. Likewise, our nose is particularly well suited to detect microbial products. Come to think of it, several microbes employ serotonin analogues and other hallucinogenic substances as part of the means of communication for their quorum sensing. What if we were taking part in microbial talk? What if through hallucinations and dreams we were taking part in that fluid world that permeates us? Perhaps it is time to consider that shamans and their experiences offer insights into those “invisible” worlds, that they might be employing some diagnostic means Western biomedicine has often lacked.

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César E. Giraldo-Herrera, PhD

César E. Giraldo-Herrera (Ph.D.) is the author of Microbes and Other Shamanic Beings (Palgrave, 2018). He is a biologist and anthropologist and currently a Research Associate at the Institute for Science, Innovation and Society, School of Anthropology and Museum Ethnography, University of Oxford.
César E. Giraldo-Herrera, PhD

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