How to Change Your Mind: What the New Science of Psychedelics Teaches Us About Consciousness, Dying, Addiction, Depression, and Transcendence

by Michael Pollan

For our species, I learned, plants and fungi with the power to radically alter consciousness have long and widely been used as tools for healing the mind, for facilitating rites of passage, and for serving as a medium for communicating with supernatural realms, or spirit worlds.

It is true that the terrifying experiences some people have on psychedelics can risk flipping those at risk into psychosis, so no one with a family history or predisposition to mental illness should ever take them.

As a young chemist working in a unit of Sandoz Laboratories charged with isolating the compounds in medicinal plants to find new drugs, Hofmann had been tasked with synthesizing, one by one, the molecules in the alkaloids produced by ergot. Ergot is a fungus that can infect grain, often rye, occasionally causing those who consume bread made from it to appear mad or possessed.

William James gave a name to this conviction: the noetic quality. People feel they have been let in on a deep secret of the universe, and they cannot be shaken from that conviction.

“Oh, the Glory!”) Pahnke concluded that the experiences of those who received the psilocybin were “indistinguishable from, if not identical with,” the classic mystical experiences reported in the literature.

In 1971, Richard Nixon declared Timothy Leary, a washed-up psychology professor, “the most dangerous man in America.” Psychedelics were nourishing the counterculture, and the counterculture was sapping the willingness of America’s young to fight. The Nixon administration sought to blunt the counterculture by attacking its neurochemical infrastructure.

Stanislav Grof believes that psychedelics loosed “the Dionysian element” on 1960s America, posing a threat to the country’s puritan values that was bound to be repulsed. (He told me he also thinks the same thing could happen again.) Roland Griffiths points out that ours is not the first culture to feel threatened by psychedelics: the reason R. Gordon Wasson had to rediscover magic mushrooms in Mexico was that the Spanish had suppressed them so effectively, deeming them dangerous instruments of paganism.

AT THE SAME TIME I was interviewing Richard Boothby and his fellow volunteers, I was reading William James’s account of mystical consciousness in The Varieties of Religious Experience in the hope of orienting myself. And indeed much of what James had to say helped me get my bearings amid the torrent of words and images I was collecting.

Yet people come out of the experience understanding these platitudes in a new way; what was merely known is now felt, takes on the authority of a deeply rooted conviction. And, more often than not, that conviction concerns the supreme importance of love.

On the back was a quotation from William Blake that, it occurred to me later, neatly aligned the way of the scientist with that of the mystic: “The true method of knowledge is experiment.”

If the experience of transcendence is mediated by molecules that flow through both our brains and the natural world of plants and fungi, then perhaps nature is not as mute as Science has told us, and “Spirit,” however defined, exists out there—is immanent in nature, in other words, just as countless premodern cultures have believed.

But while Stamets is one of the country’s most respected mycologists, he works entirely outside the academy, has no graduate degree, funds most of his own research,* and holds views of the role of fungi in nature that are well outside the scientific mainstream and that, he will gladly tell you, owe to insights granted to him by the mushrooms themselves, in the course of both close study and regular ingestion.

His extravagant claims for the powers of mushrooms and eyebrow-elevating boasts about his mushroom work with institutions like DARPA (the Pentagon’s Defense Advanced Research Projects Agency) and NIH (the National Institutes of Health) are bound to set off a journalist’s bullshit detector, rightly or—as often happens in his case—wrongly.

Over the years, we’ve found ourselves at some of the same conferences, so I’ve had several opportunities to hear his talks, which consist of a beguiling (often brilliant) mash-up of hard science and visionary speculation, with the line between the two often impossible to discern. His 2008 TED talk, which is representative, has been viewed online more than four million times.

Fungi constitute the most poorly understood and underappreciated kingdom of life on earth. Though indispensable to the health of the planet (as recyclers of organic matter and builders of soil), they are the victims not only of our disregard but of a deep-seated ill will, a mycophobia that Stamets deems a form of “biological racism.” Leaving aside their reputation for poisoning us, this is surprising in that we are closer, genetically speaking, to the fungal kingdom than to that of the plants.

I can remember the first time I heard Stamets talk about “mycoremediation”—his term for the use of mushrooms to clean up pollution and industrial waste. One of the jobs of fungi in nature is to break down complex organic molecules; without them, the earth would long ago have become a vast, uninhabitable waste heap of dead but undecomposed plants and animals.

For years now, Stamets has been talking about the vast web of mycelia in the soil as “Earth’s natural Internet”—a redundant, complexly branched, self-repairing, and scalable communications network linking many species over tremendous distances.

Stamets contends that these mycelial networks are in some sense “conscious”: aware of their environment and able to respond to challenges accordingly.

Psilocybes are saprophytes, living off dead plant matter and dung. They are denizens of disturbed land, popping up most often in the habitats created by ecological catastrophe, such as landslides, floods, storms, and volcanoes. They also prosper in the ecological catastrophes caused by our species: clear-cut forests, road cuts, the wakes of bulldozers, and agriculture. (Several species live in and fruit from the manure of ruminants.)

“Psilocybe mushrooms and civilization continue to co-evolve,” Stamets writes.

The blue pigment is in fact evidence of oxidized psilocin, one of the two main psychoactive compounds in a Psilocybe. (The other is psilocybin, which breaks down into psilocin in the body.)

The only reason I could make any sense of the image at all was that a few days earlier I had received an e-mail from Stamets referring to the theory in question: “I want to discuss the high likelihood that the Stoned Ape Theory, first presented by Roland Fischer and then popularized/restated by Terence McKenna, is probably true—[ingestion of psilocybin] causing a rapid development of the hominid brain for analytical thinking and societal bonding. Did you know that 23 primates (including humans) consume mushrooms and know how to distinguish ‘good’ from ‘bad’?”

When Paul was fourteen, John told him about magic mushrooms, and when he went off to Yale, John left behind a book, Altered States of Consciousness, that made a tremendous impression on Paul. Edited by Charles T. Tart, a psychologist, the book is a doorstop of an anthology of scholarly writings about non-ordinary mental states, covering the spectrum from dreaming and hypnosis to meditation and psychedelics.

IN A REMARKABLY SHORT SPAN of time, Stamets made himself into one of the country’s leading experts on the genus Psilocybe.

This brings us to Terence McKenna’s stoned ape theory, the epitome of all mycocentric speculation, which Stamets had wanted to make sure we discussed. Though reading is no substitute for hearing McKenna expound his thesis (you can find him on YouTube), he summarizes it in Food of the Gods (1992): Psilocybes gave our hominid ancestors “access to realms of supernatural power,” “catalyzed the emergence of human self-reflection,” and “brought us out of the animal mind and into the world of articulated speech and imagination.”

Hence, the stoned ape: by giving us the gifts of language and self-reflection psilocybin mushrooms made us who we are, transforming our primate ancestors into Homo sapiens.

In McKenna’s vision, it is the mushroom itself that helped form precisely the kind of mind—endowed with the tools of language and fired by imagination—that could best advance its interests.

Stamets believes the mycelium functions as a kind of immune system for its arboreal host, secreting antibacterial, antiviral, and insecticidal compounds that protect the trees from diseases and pests, in exchange for nourishment and habitat.

The mushroom had been growing a stone’s throw from our yurt, right on the edge of a parking spot. Stamets says that like many psilocybin species “azzies are organisms of the ecological edge. Look at where we are: at the edge of the continent, the edge of an ecosystem, the edge of civilization, and of course these mushrooms bring us to the edge of consciousness.”

THE QUESTION I KEPT returning to that weekend is this: Why in the world would a fungus go to the trouble of producing a chemical compound that has such a radical effect on the minds of the animals that eat it? What, if anything, did this peculiar chemical do for the mushroom?

I asked him if there is reason to believe that psilocybin is a defense chemical for the mushroom. Defense against pests and diseases is the most common function of the so-called secondary metabolites produced in plants. Curiously, many plant toxins don’t directly kill pests, but often act as psychostimulants as well as poisons, which is why we use many of them as drugs to alter consciousness. Why wouldn’t plants just kill their predators outright? Perhaps because that would quickly select for resistance, whereas messing with its neurotransmitter networks can distract the predator or, better still, lead it to engage in risky behaviors likely to shorten its life. Think of an inebriated insect behaving in a way that attracts the attention of a hungry bird.

Even if psilocybin in mushrooms began as “an accident of a metabolic pathway,” the fact that it wasn’t discarded during the course of the species’ evolution suggests it must have offered some benefit.

Presumably animals with a taste for altered states of consciousness have helped spread psilocybin far and wide. “The strains of a species that produced more rather than less psilocybin and psilocin would tend to be favored and so gradually become more widespread.”

Eaten in small doses, psychedelic mushrooms might well increase fitness in animals, by increasing sensory acuity and possibly focus as well. A 2015 review article in the Journal of Ethnopharmacology reported that several tribes around the world feed psychoactive plants to their dogs in order to improve their hunting ability.

Much like genetic mutations, most of these novelties will prove disastrous and be discarded by natural selection. But the laws of probability suggest that a few of the novel behaviors might end up being useful, helping the individual, the group, and possibly the species to adapt to rapid changes in their environment.

Homo sapiens might have arrived at one of those periods of crisis that calls for some mental and behavioral depatterning. Could that be why nature has sent us these psychedelic molecules now?

“Plants and mushrooms have intelligence, and they want us to take care of the environment, and so they communicate that to us in a way we can understand.” Why us? “We humans are the most populous bipedal organisms walking around, so some plants and fungi are especially interested in enlisting our support. I think they have a consciousness and are constantly trying to direct our evolution by speaking out to us biochemically. We just need to be better listeners.”

“Mushrooms have taught me the interconnectedness of all life-forms and the molecular matrix that we share,” he explains in another one.

“I think Psilocybes have given me new insights that may allow me to help steer and speed fungal evolution so that we can find solutions to our problems.” Especially in a time of ecological crisis, he suggests, we can’t afford to wait for evolution, unfolding at its normal pace, to put forth these solutions in time. Let the depatterning begin.

The day before, Stamets had given me a tour of the labs and grow rooms at Fungi Perfecti, the company he founded right out of college.

He too hears nature’s voice, and it is his imagination—wild as it often is—that allows him to see systems where others have not, such as what is going on beneath our feet in a forest. I’m thinking, for example, of the “earth’s Internet,” “the neurological network of nature,” and the “forest’s immune system”—three Romantic-sounding metaphors that it would be foolish to bet against.

Our science and technology encourage us in precisely the opposite direction, toward the objectification of nature and of all species other than our own. Surely we need to acknowledge the practical power of this perspective, which has given us so much, but we should at the same time acknowledge its costs, material as well as spiritual. Yet that older, more enchanted way of seeing may still pay dividends, as it does (to cite just one small example) when it allows Paul Stamets to figure out that the reason honeybees like to visit woodpiles is to medicate themselves, by nibbling on a saprophytic mycelium that produces just the right antimicrobial compound that the hive needs to survive, a gift the fungus is trading for . . . what? Something yet to be imagined.

“Everything is interaction and reciprocal,” wrote Humboldt, and that felt very much the case, and so, for the first time I can remember, did this: “I myself am identical with nature.”

There had also been, I felt, an opening of the heart, toward my parents, yes, and toward Judith, but also, weirdly, toward some of the plants and trees and birds and even the damn bugs on our property. Some of this openness has persisted. I think back on it now as an experience of wonder and immanence.

So did Aldous Huxley “make sense” of the modern psychedelic experience, or did he in some sense invent it?

After learning that mescaline induced hallucinations much like those reported by schizophrenics, the two researchers began to explore the idea that the disease was caused by a chemical imbalance in the brain. At a time when the role of brain chemistry in mental illness had not yet been established, this was a radical hypothesis. The two psychiatrists had observed that the molecular structure of mescaline closely resembled that of adrenaline. Could schizophrenia result from some kind of dysfunction in the metabolism of adrenaline, transforming it into a compound that produced the schizophrenic rupture with reality? No, as it would turn out.

The fact that such a vanishingly small number of LSD molecules could exert such a profound effect on the mind was an important clue that a system of neurotransmitters with dedicated receptors might play a role in organizing our mental experience. This insight eventually led to the discovery of serotonin and the class of antidepressants known as SSRIs.

Coined by an English psychiatrist named Ronald Sandison, “psycholytic” means “mind loosening,” which is what LSD and psilocybin seem to do—at least at low doses.

This suggested that the drugs could be used as an aid to talking therapy, because at these doses the patients’ egos remained sufficiently intact to allow them to converse with a therapist and later recall what was discussed.

Mescaline flung open what William Blake had called “the doors of perception,” admitting to our conscious awareness a glimpse of the infinite, which is always present all around us—even in the creases in our trousers!—if only we could just see.