At least at the beginning, the Spring Grove psychedelic work enjoyed lots of public support. In 1965, CBS News broadcast an admiring hour-long “special report” on the hospital’s work with alcoholics, called LSD: The Spring Grove Experiment. The response to the program was so positive that the Maryland state legislature established a multimillion-dollar research facility on the campus of the Spring Grove State Hospital, called the Maryland Psychiatric Research Center.

“The true method of knowledge is experiment.”

(The biggest organism on earth is not a whale or a tree but a mushroom—a honey fungus in Oregon that is 2.4 miles wide.)

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.

But while Stamets urges extreme circumspection in amateurs hoping to identify Psilocybes, he also equips the mushroom hunter who hasn’t been completely discouraged with something he calls “The Stametsian Rule”: a three-pronged test that, he (sort of) assures us, can head off death and disaster. “How do I know if a mushroom is a psilocybin producing species or not?” “If a gilled mushroom has purplish brown to black spores, and the flesh bruises bluish, the mushroom in question is very likely a psilocybin-producing species.” This is definitely a big help, though I wouldn’t mind something more categorical than “very likely.” He then offers a sobering caveat. “I know of no exceptions to this rule,” he adds, “but that does not mean there are none!”

“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’?”

So when R. Gordon Wasson approached Life magazine with his story, he could not have knocked on a more receptive door. Life gave him a generous contract that, in addition to the princely sum of eighty-five hundred dollars, granted him final approval on the editing of his article, as well as the wording of headlines and captions.

The headline is the first known reference to “magic mushrooms,” a phrase that, it turns out, was coined not by a stoned hippie but by a Time-Life headline writer.

The logical next question presented itself to the Wassons—“What kind of mushroom was once worshipped, and why?”—and with that question in hand they embarked on a thirty-year quest to find the divine mushroom. They hoped to obtain evidence for the audacious theory that Wasson had developed and that would occupy him until his death: that the religious impulse in humankind had been first kindled by the visions inspired by a psychoactive mushroom.

For it was Schultes who first identified teonanácatl—the sacred mushroom of the Aztecs and their descendants—as well as ololiuqui, the seeds of the morning glory, which the Aztecs also consumed sacramentally and which contain an alkaloid closely related to LSD.

Their reticence was not surprising. The sacramental use of psychoactive mushrooms had been kept secret from Westerners for four hundred years, since shortly after the Spanish conquest, when it was driven underground.

Indians were interrogated and tortured into confessing the practice, and mushroom stones—many of them foot-tall chiseled basalt sculptures of the sacred fungi, presumably used in religious ceremonies—were smashed. The Inquisition would bring dozens of charges against Native Americans for crimes involving both peyote and psilocybin, in what amounted to an early battle in the war on drugs—or, to be more precise, the war on certain plants and fungi. In 1620, the Roman Catholic Church declared that the use of plants for divination was “an act of superstition condemned as opposed to the purity and integrity of our Holy Catholic Faith.”

ON THE NIGHT OF JUNE 29–30, 1955, R. Gordon Wasson experienced the sacred mushrooms firsthand. On his third trip to Huautla, he had persuaded María Sabina, a sixty-one-year-old Mazatec and a respected curandera in the village, to let him and his photographer not only observe but take part in a ceremony in which no outsider had ever participated.

Stamets became good friends with McKenna during the last few years of his life, and ever since McKenna’s death (at age fifty-three, from brain cancer), he has been carrying the stoned ape’s torch, recounting McKenna’s theory in many of his talks. Stamets acknowledges the challenges of ever proving it to anyone’s satisfaction yet deems it “more likely than not” that psilocybin “was pivotal in human evolution.”

Stamets requested that I not publish the exact location where we went hunting for Psilocybe azurescens. But what I can say is that there are three public parks bordering the wide-open mouth of the Columbia—Fort Stevens, Cape Disappointment, and the Lewis and Clark National Historical Park—and we stayed at one of them.

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.”

It is difficult to read about Samorini’s lovely theory without thinking about our own species and the challenging circumstances in which we find ourselves today. 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.”

“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.

Along the way, the CIA dosed its own employees and unwitting civilians with LSD; in one notorious case that didn’t come to light until the 1970s, the CIA admitted to secretly giving LSD to an army biological weapons specialist named Frank Olson in 1953; a few days later, Olson supposedly jumped to his death from the thirteenth floor of the Statler Hotel in New York.

Bored, he went up onto the roof of his building in North Beach and took a hundred micrograms of acid—Fadiman’s creativity dose. As he looked toward downtown while wrapped in a blanket, it appeared that the streets lined with buildings were not quite parallel.

In their first experiments, Leary and Alpert administered psilocybin to hundreds of people of all sorts, including housewives, musicians, artists, academics, writers, fellow psychologists, and graduate students, who then completed questionnaires about their experiences.

Alpert and Leary appear to be the only Harvard professors fired in the twentieth century.

The rest of his life is an improbable 1960s tragicomedy featuring plenty of courtrooms and jails (twenty-nine in all) but also memoirs and speeches and television appearances, a campaign for governor of California (for which John Lennon wrote, and the Beatles recorded, the campaign song, “Come Together”), and a successful if somewhat pathetic run on the college lecture circuit teamed up with G. Gordon Liddy.

It is one of the richer ironies of psychedelic history that Kesey had his first LSD experience courtesy of a government research program conducted at the Menlo Park Veterans Hospital, which paid him seventy-five dollars to try the experimental drug. Unbeknownst to Kesey, his first LSD trip was bought and paid for by the CIA, which had sponsored the Menlo Park research as part of its MK-Ultra program, the agency’s decade-long effort to discover whether LSD could somehow be weaponized.

This is where psychedelics come in. By quieting the default mode network, these compounds can loosen the ego’s grip on the machinery of the mind, “lubricating” cognition where before it had been rusted stuck. “Psychedelics alter consciousness by disorganizing brain activity,” Carhart-Harris writes. They increase the amount of entropy in the brain, with the result that the system reverts to a less constrained mode of cognition.

When we met, he offered examples of scientists whose own experiences with LSD had supplied them with insights into the workings of the brain. Too much entropy in the human brain may lead to atavistic thinking and, at the far end, madness, yet too little can cripple us as well. The grip of an overbearing ego can enforce a rigidity in our thinking that is psychologically destructive. It may be socially and politically destructive too, in that it closes the mind to information and alternative points of view.

Under the weight of this existential crisis, one’s horizon shrinks, one’s emotional repertoire contracts, and one’s focus narrows as the mind turns in on itself, shutting out the world. Loops of rumination and worry come to occupy more of one’s mental time and space, reinforcing habits of thought it becomes ever more difficult to escape.

Matt Johnson believes that psychedelics can be used to change all sorts of behaviors, not just addiction. The key, in his view, is their power to occasion a sufficiently dramatic experience to “dope-slap people out of their story. It’s literally a reboot of the system—a biological control-alt-delete.

Dying, depression, obsession, eating disorders—all are exacerbated by the tyranny of an ego and the fixed narratives it constructs about our relationship to the world. By temporarily overturning that tyranny and throwing our minds into an unusually plastic state (Robin Carhart-Harris would call it a state of heightened entropy), psychedelics, with the help of a good therapist, give us an opportunity to propose some new, more constructive stories about the self and its relationship to the world, stories that just might stick.

It was Ross who first told me the story of Bill W., the founder of AA, how he got sober after a mystical experience on belladonna and in the 1950s sought to introduce LSD into the fellowship.

Watts’s interviews uncovered two “master” themes. The first was that the volunteers depicted their depression foremost as a state of “disconnection,” whether from other people, their earlier selves, their senses and feelings, their core beliefs and spiritual values, or nature. Several referred to living in “a mental prison,” others to being “stuck” in endless circles of rumination they likened to mental “gridlock.” I was reminded of Carhart-Harris’s hypothesis that depression might be the result of an overactive default mode network—the site in the brain where rumination appears to take place.

The second master theme was a new access to difficult emotions, emotions that depression often blunts or closes down completely. Watts hypothesizes that the depressed patient’s incessant rumination constricts his or her emotional repertoire. In other cases, the depressive keeps emotions at bay because it is too painful to experience them.

Like electroconvulsive therapy for depression, which it in some ways resembles, psychedelic therapy is a shock to the system—a “reboot” or “defragging”—that may need to be repeated every so often.

He quotes an expert on anxiety who suggests we should think of the two disorders as “fraternal twins”: “Depression is a response to past loss, and anxiety is a response to future loss.”

“Capture” is his term for the common mechanism underlying addiction, depression, anxiety, mania, and obsession; in his view, all these disorders involve learned habits of negative thinking and behavior that hijack our attention and trap us in loops of self-reflection.

On the spectrum he lays out (in his entropic brain article) ranging from excessive order to excessive entropy, depression, addiction, and disorders of obsession all fall on the too-much-order end. (Psychosis is on the entropy end of the spectrum, which is why it probably doesn’t respond to psychedelic therapy.)

So many of the volunteers I spoke to, whether among the dying, the addicted, or the depressed, described feeling mentally “stuck,” captured in ruminative loops they felt powerless to break. They talked about “prisons of the self,” spirals of obsessive introspection that wall them off from other people, nature, their earlier selves, and the present moment. All these thoughts and feelings may be the products of an overactive default mode network, that tightly linked set of brain structures implicated in rumination, self-referential thought, and metacognition—thinking about thinking. It stands to reason that by quieting the brain network responsible for thinking about ourselves, and thinking about thinking about ourselves, we might be able to jump that track, or erase it from the snow.

“The ego keeps us in our grooves,” as Matt Johnson puts it. For better and, sometimes, for worse. For occasionally the ego can become tyrannical and turn its formidable powers on the rest of us.* Perhaps this is the link between the various forms of mental illness that psychedelic therapy seems to help most: all involve a disordered ego—overbearing, punishing, or misdirected.

It was Brewer, you’ll recall, who discovered that the brains of experienced meditators look much like the brains of people on psilocybin: the practice and the medicine both dramatically reduce activity in the default mode network.

The posterior cingulate cortex is a centrally located node within the default mode network involved in self-referential mental processes. Situated in the middle of the brain, it links the prefrontal cortex—site of our executive function, where we plan and exercise will—with the centers of memory and emotion in the hippocampus. The PCC is believed to be the locus of the experiential or narrative self; it appears to generate the narratives that link what happens to us to our abiding sense of who we are. Brewer believes that this particular operation, when it goes awry, is at the root of several forms of mental suffering, including addiction.

Aren’t we identical with our ego? What’s left of us without it? The lesson of both psychedelics and meditation is the same: No! on the first count, and More than enough on the second. Including this lovely landscape of the mind, which became lovelier still when I let that ridiculous steel structure float away, taking its shadow with it.

It is all too easy to dismiss what unfolds in our minds during a psychedelic journey as simply a “drug experience,” and that is precisely what our culture encourages us to do. Matt Johnson made this point the first time we spoke: “Let’s say you have some nineteen-year-olds taking mushrooms at a party. One of them has a profound experience. He’s come to understand what God is, or his connection to the universe. What do his friends say? ‘Oh, man, you had too much last night! No more mushrooms for you!’