On​ the remote island of Siberut off the west coast of Sumatra, the Mentawai have a well-documented tradition of shamans: individuals known as sikerei heal people by communing with spirits. Manvir Singh, in the middle of his doctoral research in human evolutionary biology, went there in 2014 to undertake fieldwork. Sikerei were easy to spot, with their long hair, loincloths, strings of beads and spidery tattoos, which traced patterns and broken lines up their spines, limbs and torsos and across their faces. Singh was hoping to embed himself in a traditional community and witness its ceremonies. But during the 1970s most of them had been relocated from their longhouses in the forest to government-built villages; by the 1990s guides were organising ‘tribal tours’ for foreigners and marketing the sikerei as a spectacle of ‘living Stone Age culture’. A long and muddy trek to an isolated longhouse in the interior of the island led him not to a pristine shamanic community but to a small family subsisting in isolation with a few pigs. Exhausted by the tropical heat, unable to grasp the language or to find what he was looking for, he abandoned this first visit to Siberut after a fortnight and took the ferry back to Sumatra.

Singh would have no such problems, in subsequent years, connecting with shamans on visits to the Peruvian Andes and the Amazon. Here, their ceremonies are not merely open to tourists but have been reconceived with them in mind. They are the basis of lucrative local businesses, with a dollar-power that draws experienced shamans from far-flung mestizo communities, where their traditional role is low in status, economically precarious and fraught with disputes and vendettas. There is much more money and status to be had conducting visitors on medico-spiritual ‘journeys’ of healing, personal growth and self-actualisation under the influence of ayahuasca, cacti and magic mushrooms.

Traditionally, it was the shaman who swallowed or sniffed intoxicating plants as a way of gaining access to the world of the spirits, but the new Western clients are focused on their own psychedelic experiences. They rarely show any interest in Indigenous cosmology or in the local uses of the ceremonies, which are typically in healing physical illness or answering questions about lost possessions or a suspicious run of misfortune. The visitors are steered away from shamanism’s dark undercurrents, its involvement with sorcery, evil spirits and psychic warfare, and towards what Singh characterises as psychedelic-assisted psychotherapy, to help with mental health issues such as depression or trauma.

The world of the shaman is always changing. Indeed the ayahuasca traditions of many Amazon tribal groups date back only as far as their encounter with Jesuit missionaries and the rubber boom of the early 20th century. The plant sources of the most potent hallucinogen in the ayahuasca brew, DMT (dimethyltryptamine), were once typically powdered and sniffed or propelled up into the sinuses with blowpipes. The antiquity of this practice was confirmed with the find in 2008 of a thousand-year-old ritual bundle in an Andean cave containing the powdered ingredients of ayahuasca together with a bone snuffing tube. Only after previously isolated communities were threaded into a network in the years around 1900, notably by Black rubber tappers who encountered ayahuasca in the forest and adapted its use for Christian worship in the cities, did the secret of macerating and boiling together a specific combination of plants to produce a brew for oral consumption spread across the region and replace older traditions.

Despite this long history of mutual influence, the potential for culture shock remains, on both sides. One veteran shaman, returning from his first experience performing at a top-dollar eco-lodge, asked the ayahuasca researcher Stephan Beyer why these people had come halfway round the world to see him when they weren’t sick. And why do they all hate their parents? Yet many shamans are content to trade old practices for the new, and see the Western visitors as one more novelty in a rapidly changing and increasingly joined-up world. The visions of ayahuasqueros now commonly include futuristic Western surgeries and clinics, X-ray machines and brain scanners operated by spirits or extra-terrestrials dressed in surgical scrubs. Singh quotes a Mazatec mushroom healer: ‘We have to adapt to survive,’ he shrugs, ‘and we have to help those who need the medicine.’

Singh returned to Siberut, and after struggling for two months with climate, language, exhaustion, infections and motorbike injuries, finally found a longhouse upriver where he could observe sikerei rituals and in due course participate in them. When he asked Mentawai people their reasons for consulting sikerei, they invariably described physical illnesses: ‘Not a single person mentioned an emotional or cognitive issue.’ The predominant image of shamanism in the modern world reflects the hallucinatory Amazon ceremonies – the assumption is that shamanism is defined by the use of consciousness-altering plants for personal transformation – yet Singh’s survey of the literature suggests that only around 5 per cent of shamanic practices around the world involve mind-altering plants or fungi. The ‘healing journey’ offered to Western visitors owes considerably more to 20th-century depth psychology than to non-Western cultures.

The mismatch between Western and Indigenous perspectives was evident in the encounter that kickstarted this modern mode of engagement, in the cloud forests of southern Mexico in 1955. R. Gordon Wasson, a vice president of J.P. Morgan and amateur mushroom hunter, was convinced that hallucinogenic mushrooms had been used in the sacrament of an ancient and long-suppressed pre-Christian global religion. On the trail of a Mazatec tradition that reportedly survived in the mountain villages of Oaxaca, he sought out a traditional healer or curandera, María Sabina, and asked her to perform a ritual on the pretext of healing his absent son. Under the influence of the mushrooms, Wasson had ecstatic visions of soul flight and the ineffable presence of the divine, which he wrote up at length for Life magazine in 1957 in a piece titled ‘Seeking the Magic Mushroom’. Sabina, however, understood none of this: she was a devout Catholic, who communicated with the divine in church on Sundays. For her the mushrooms were her ‘children’ or ‘little saints’, whose special power was to cure sickness.

‘Shamanism’, as a concept, is of course a Western invention, and from the earliest cross-cultural encounters it was defined in opposition to Western norms as demonic, primitive or irrational. The first published account, from the Dutch explorer Nicolaas Witsen’s trip to Siberia in the 1660s, included a woodcut of a shaman in animal furs and antlers, dancing and beating a drum, titled ‘Tungus Shaman, or Priest of the Devil’. Subsequent accounts during the Enlightenment played down the spiritual powers of the shaman and instead stressed his fraudulence: Diderot, in his Encyclopédie of 1751-65, defined the shaman as a performer or ‘juggler’ who performs ‘tricks that seem supernatural to an ignorant and superstitious people’. By the early 20th century, the modern taxonomy of mental illness provided the terms in which to theorise that shamanism gave a social role to abnormal individuals who in the West might be diagnosed with epilepsy or schizophrenia.

This was the backdrop to Mircea Eliade’s Shamanism: Archaic Techniques of Ecstasy, which appeared in French in 1951 and can be said to have created today’s Western image of the shaman. According to Eliade, shamans were neither tricksters nor schizophrenics but practitioners of the original, ‘archaic’ religion of prehistory, survivals from an era when humans cultivated the ability to commune with animals, nature and the spirit world. The traditional hunters of Siberia had maintained this ability, together with the cosmology that underpinned it: a three-tiered universe with a heaven above and a netherworld beneath, linked by an ‘axis mundi’ or ‘world tree’. The shaman’s powers were accessed by ‘soul flight’ into the upper realm.

Central to this practice was ‘ecstasy’, the ‘going out of the self’ that brought the shaman into contact with the sacred. This was accomplished by wearing animal skins or other non-human disguises, and by drumming, singing and performing other ‘techniques of ecstasy’ that were, the story went, universal at the dawn of humanity but had long been forgotten outside traditional Arctic societies. For Eliade, the ‘archaic’ shamanism of Siberia was more authentic than the similar practices it had seeded throughout the world. He regarded the techniques of ecstasy found in, among other places, Korea, Tibet, Indonesia and Africa – possession by gods or ancestors, the summoning of spirits and, notably, the consumption of hallucinogenic plants – as ‘late’ or ‘degenerate’.

Eliade had never visited Siberia, met a shaman or observed a shamanic ceremony. The task he set himself as a historian of comparative religion was to assemble what Edmund Leach called ‘snippets of exotic ethnography’ into a suggestive portrait of a lost world before civilisation. Like near contemporaries such as Carl Jung and Joseph Campbell, his was a work of synthesis, densely sourced and annotated but sweepingly Romantic in style and scope. It reflected his own Orthodox Christian background, privileging descriptions of heavenward journeys and finding echoes of the shaman in the Christian mystics, while minimising evident connections to other traditions such as Buddhism. Subsequent scholarship has shown that soul journeying, possession, intoxication and other techniques of ecstasy are all widespread and frequently overlap, around the world and in Siberia itself. The Finnish researcher Anna-Leena Siikala found that the Evenki people of central and eastern Siberia, speakers of the Tungus language from which ‘shaman’ derives, use spirit summoning, possession and soul journeying together, often in a single session.

Eliade’s magnum opus was translated into English in 1964, so was conveniently to hand for the Westerners who had been inspired by Wasson’s mushroom trip. In the late 1960s Carlos Castaneda began publishing his series of bestselling books detailing his journeys into non-ordinary reality with the mysterious Mexican shaman Don Juan. These turned out to be a compendium of ethnographic excerpts, fictionalised from anthropological accounts of spirit journeys and traditional healing from tribal Mexico and the Amazon basin, often involving hallucinogenic plants. Castaneda studied at UCLA with several of the anthropologists on whose work he draws, including Barbara Myerhoff and Peter Furst; the university was also home to such scholars as Marija Gimbutas and Carlo Ginzburg, who had found shamanic traces in the archaeology and folklore of prehistoric and medieval Europe.

This new turn displaced armchair ethnography with participant-observation, which entered more imaginatively into the world of its subjects and loosened the grip of the old evolutionary narrative in which shamans represent a pristine form or lowest rung of development, to be replaced by a priestly hierarchy once societies became more civilised and stratified. Along the way, the idea grew that the archaic techniques of shamanism could be integrated into the modern quest for self-actualisation. The anthropologist Michael Harner, who studied and drank ayahuasca with Shipibo-Conibo and Jívaro shamans in the Upper Amazon and taught at Berkeley and elsewhere, boiled his experiences and Eliade’s theories down to a programme he called ‘core shamanism’, which became a staple of New Age retreats and workshops: group drumming ceremonies that induced a ‘shamanic state of consciousness’, and communion with ‘power animals’ or ‘guardian spirits’. Like Harner, Castaneda developed and marketed a practice that sidestepped the use of illicit drugs, in his case ‘tensegrity’, a combination of ‘magical passes’ with dance and breathwork exercises intended to cultivate the shaman’s powers and ‘warrior-traveller path’. A younger generation of anthropologists argued that Eliade had constructed an idiosyncratic vision of prehistoric religion which he had unhelpfully named ‘shamanism’; at the same time, the term was taking on a new set of meanings unfamiliar to its Indigenous practitioners.

The subtitle of Singh’s book describes shamanism as a religion, though he doesn’t refer to it that way in the text (the blurb on the dust jacket calls it a ‘spiritual practice’). One could even dispute whether the suffix ‘-ism’ is appropriate: is ‘shamanism’ analogous to other religious frameworks such as Judaism or Hinduism? The equivalent to these would be animism, the worldview that underlies shamanism, according to which the natural world is peopled by spirits, ancestors and other non-human entities. Singh sets these questions aside, instead approaching shamanism as a set of practical techniques and reducing it to the simplest possible formula: ‘The shaman is a specialist who, through non-ordinary states, engages with unseen realities and provides services like healing and divination.’

In the​ 1980s, Michael Winkelman conducted a global survey of shamanic practices and built a database that broke them down according to around 260 variables: whether spirits are summoned, drumming or dancing incorporated, talismanic objects used, and so on. One effect was to dislodge Siberia and soul flight from the privileged position that Eliade had given them. The database also demonstrated that the use of consciousness-altering plants was the exception rather than the rule, especially once the context was broadened beyond the Americas. Along with the work of subsequent researchers who have tracked the emergence of shamanism in isolated cultures, the database supports Singh’s contention that, rather than diffusing from a Eurasian homeland, it is the product of convergent cultural evolution: ‘Something about human minds or societies fates the practice to develop’ in similar situations.

In the popular view of shamanism, the first part of Singh’s definition – ‘non-ordinary states’ – is imagined through the Western lens of psychedelic experience, with its signature qualities of ego death and spiritual transformation. Harner’s ‘core shamanism’, for instance, puts the emphasis on achieving the ‘integrative’ or ‘shamanic state of consciousness’. But Eliade’s ‘ecstasy’, and the many varieties of ‘trance’ and ‘possession’, are less about the shaman’s mental processes and more to do with the communication they facilitate. The goal isn’t to alter one’s consciousness or enter a separate ‘spirit realm’, but something more like code-switching to a mode of reality in which it is possible to interact with the non-human persons who are present but invisible in normal life.

This code-switching entails not merely an altered relation to the external world but a performance that acts it out, allowing the contact with unseen reality to be witnessed by others. The shaman’s performance is both a ritual enactment that operates within well-established conventions – costume, drumming, dance – and a genuine drama, chaotic and unpredictable: an ‘ecstasy’ in which the shaman leaves their body and loses control, often spectacularly. Singh draws comparison with the use in English of terms such as ‘inspired’ and ‘genius’, with their roots in spirits and possession. As the British ethnographer Carmen Blacker observed at shamanic ceremonies in Japan in the 1960s, a ‘violent, inhuman and strange’ performance was considered impressive, while decorous wand-waving was ‘weak and unconvincing’. The performance is still more impressive if the shaman has no memory of it afterwards.

The ambiguous status of such performances invites questions about the line between authenticity and fakery. Enlightenment observers confidently concluded that the entire performance was a fraud perpetrated on the credulous, but the line is much blurrier. Often neither shamans nor their Indigenous audiences will be under any illusions. An Amazonian ayahuasquero who sucks at a patient’s stomach before spitting a concealed thorn into his hand knows exactly what he is doing, and performs his sleight of hand with much dramatic gagging and retching. The Danish anthropologist Rane Willerslev, accompanying a group of Siberian Yukaghir people on a bear hunt, was struck by the way the hunters mocked the taboos and rituals involving the dead bear and shouted coarse insults at their helping-spirit. When he asked them about it, they laughed it off, telling him: ‘We are just having fun … without laughter there will be no luck.’ Willerslev left this story out of his scholarly book on Yukaghir animism, and wondered how many other anthropologists had made similar editorial decisions. ‘Shamans both believe and do not believe,’ Singh concludes. ‘They lie. They use ruses and subterfuge. But they are humans, too. They experience the vivid super-reality of some non-ordinary states. And they notice that some patients recover after healing ceremonies.’

This last point is significant: shamanism ‘works’, at least sometimes, and certainly has better odds of success than leaving things to chance. This is partly because it is deployed in situations of human powerlessness, such as illness, bad weather or curses, where it can be given the credit for good fortune. But it is also a potent form of what medical anthropologists call ‘therapeutic emplotment’: creating a narrative in which the source of distress has been identified, evil influences neutralised and the path to recovery signposted. It sets up a positive feedback loop which amplifies improvements and erodes ingrained beliefs that the patient is cursed, broken or helpless. And it does all this in a supportive social environment in which the individual’s suffering is publicly recognised and shared.

Shamanism is, then, a social phenomenon, which serves others and involves their participation. Paradoxically, perhaps, this requires that shamans be situated outside social norms. In Siberut, Singh noticed that the sikerei, as well as marking themselves out with tattoos and ornaments, were prohibited from eating certain foods, including delicacies such as eels, and that they typically abstained from sex. Other Mentawai explained that the bodies of sikerei were different: regular people were simata, a word that also means ‘raw’ or ‘unripe’, while sikerei also means ‘ripe’ or ‘cooked’. Singh coins the term ‘xenising’ for the forms of self-othering that shamans practise as visible signs of their spiritual power and outsider status. Tattoos and other body modifications are common, along with fasting and other forms of abnegation; initiation can involve ordeals such as taking poison, prolonged exposure to the elements or chopping off a finger joint. Shamans are more commonly men than women, but the men often disrupt gender binaries by adopting women’s dress and roles. The Iban shamans of Borneo, for instance, at least until recent mass Christianisation, included a high-status cadre known as manang bali, ‘transformed shamans’, who dressed and acted like women, and even took husbands. In 1863 the white rajah of Sarawak, Charles Brooke, was astonished when a manang bali lectured him on the proper conduct of a raid against Sarawak’s neighbours, the Kayan: ‘I was dreadfully enraged at this ancient personage, who was dressed in woman’s clothes.’ They never joined men’s hunting expeditions and rarely assisted women in their domestic chores, remaining a transgender law unto themselves.

Singh presents shamanism ‘foremost as a mind technology’, which ‘assures people a practitioner can perform the extraordinary’. Yet the box of psychological tricks is only half the picture: it has to be complemented with an appropriate theatre, a social context in which to operate. Here Singh’s ideas are less well developed, perhaps because attempting to define a ‘shamanic culture’ tends to usher in an evolutionary narrative he wishes to avoid, in which the phenomenon is confined to ‘primitive’ societies. In the final section of the book he moves in the opposite direction, considering ways in which shamanism might be opened up or extended beyond its traditional milieux.

The Holy Spirit Movement in Uganda, which stirred a mass uprising in the north of the country in the late 1980s, was led most unusually by a 30-year-old woman called Alice Lakwena who announced that she was a healer and clairvoyant, possessed by the spirit of a dead Italian officer who spoke 74 languages. Before this, she had been a village fishmonger who was abandoned by two husbands after failing to bear children. Now she stood at the head of an army of thousands, who worshipped her as a divinity and adopted her rituals to protect themselves against bullets and bombs as they took part in the insurgency against President Yoweri Museveni’s government. They were eventually halted by Museveni’s army as they approached Kampala, and Lakwena ended her days in a Kenyan refugee camp. The fighting remnants rallied around another messianic leader, Joseph Kony, whose Lord’s Resistance Army ranged across the region, kidnapping and conscripting an estimated sixty thousand children. The LRA was eventually broken as a fighting force, but Kony’s whereabouts are still unknown.

Lakwena was clearly, by Singh’s definition, a shaman: ‘She entered altered states, interacted with unseen agents, and provided services.’ She also started a new religion and waged a civil war. Similar prophetic and millenarian uprisings are abundantly documented across the globe: the ‘cargo cults’ of Melanesia, the Ghost Dance of the Plains tribes in the US in 1890, the South-East Asian hill tribes surveyed by James C. Scott in The Art of Not Being Governed (2009). Were their rebel messiahs shamans too? Where do we draw the line? Some of the Old Testament prophets, for example, received their visions while asleep or in a trance state named, in the Greek translations of the third century BCE, ‘ekstasis’; many prophesied with the divine spirit ‘on’ them, and Ezekiel describes a soul flight that transported him to the valley of dry bones. They emerged in an ancient Near East that was rife with prophets, oracles, healers and miracle-workers whose powers derived from trance or possession.

Singh also finds shamanic resonances in unexpected corners of a disenchanted Western modernity. Financial consultants and hedge fund managers, he suggests, wrangle uncertainty with a performance of expertise that often amounts to little more than smoke and mirrors. Psychedelic therapists appropriate the rhetoric and glamour of shamanism for Western psychiatric ends. Charismatic Christian leaders speak in tongues and perform rituals of prayer and miraculous healing in their megachurches and on TV shows. When we watch the evangelical pastor Rodney Howard-Browne enter a trance as he lays his hands on Donald Trump in the White House, our jarred response to the irruption of the irrational into our secular world might be an echo of Diderot’s reflexive disgust at the jugglers and impostors of 18th-century Siberia.

Singh ends with a lament for the decline of comparative anthropology: as the discipline shifted to intensive fieldwork, ‘studying patterns became taboo’ and ‘talk of universals’ became ‘especially seditious’. Yet doesn’t the attempt to determine what shamanism is and is not by sifting through an endless array of similarities and differences recall the systematisers of Victorian armchair anthropology, from whom the discipline had to free itself in order to get closer to the facts and worldviews of the cultures being studied? As Franz Boas might have argued, the true task is to learn about the practices and role of the sikerei among the Mentawai, rather than to use these observations to construct a broader theory. Singh’s attempt to reduce shamanism to a set of ‘mind technologies’ leads us out of Eliade’s pristine cul-de-sac of Siberian reindeer hunters into a far more expansive landscape, but strips it of the social relations that characterise its most distinctive forms.