BY BEN THOMAS | Original illustration for Ember by Flo Meissner
In his 1971 bestseller Be Here Now, Harvard psychologist Baba Ram Dass (born Richard Alpert) tells a famous anecdote about the Indian guru Maharajji. According to the story, Maharajji asked for some “medicine” from Ram Dass, who gave him a whopping 915 micrograms of LSD—nearly triple a standard dose—only to find that “nothing happened”! The guru’s mind, apparently, was far too enlightened to be altered by mere chemicals.
Understandably, this story has raised a lot of eyebrows over the years. Psychedelic researcher Terrence McKenna questioned whether anyone could be unaffected by such a massive quantity of LSD, and suggested that Maharajji faked the dose through sleight of hand. High Times magazine reported that Ram Dass confessed to fabricating the whole story—a claim Ram Dass denied, forcing High Times to print a retraction in which the journalist admitted he’d forgotten who told him about Dass’s confession. Today, most experts remain skeptical.
But even if Dass’s story is pure fiction, he used it to make a valid point: Psychedelics are not the only routes to mind-alteration. Certain forms of meditative practice can evoke equally intense psychotropic experiences, including glowing geometric imagery, and even encounters with otherworldly beings. Through sustained concentration, these visions can become every bit as vivid as psychedelic trips—and they may be healthier and more sustainable, too.
How do meditators achieve such experiences? Why do people cultivate them in the first place? To find out, let’s take a closer look at the theory behind these practices—and learn what modern neuroscience is discovering about the mind’s power to alter itself.
Mindfulness meditation is wildly popular these days—and with good reason. This simple practice of “following the breath,” while observing thoughts and feelings as they come and go, has been shown to reduce stress, strengthen attention, and improve emotional regulation. Over time, mindfulness meditation even changes the physical structure of the brain, reducing the size of fear-related areas, while thickening areas involved in rational awareness.
As powerful as mindfulness can be, though, it’s only one “level” of meditation practice. As a meditator grows more proficient, they may choose to focus on a specific object while they sit in a mindful state of consciousness. In the Mahayana Buddhist tradition, for example, many people chant and meditate on the mantra, “Om mani padme hum”—whose meaning is considered less important than the attention one focuses on the sounds themselves.
Mindfulness meditation even changes the physical structure of the brain, reducing the size of fear-related areas, while thickening areas involved in rational awareness.
Some schools of Buddhism and Hinduism also teach mandala meditation. Each of the shapes, colors, and design elements within a mandala symbolizes one component of a complex spiritual teaching—and by visualizing the mandala as a whole, meditators seek to directly experience the concept itself. In Vajrayana Buddhism, which is prevalent in Tibet, the practitioner mentally constructs the mandala piece-by-piece, focusing on it with such intensity that it becomes fixed in the mind’s eye.
And in some cases, these visuals can become surprisingly real.
Jared Lindahl, a psychiatrist at Warren Wilson College, has spent much of his career studying meditation. In 2014, his team published a scientific paper on what he calls “light experiences”—bright spots, waves, light-rays, and star-like constellations that many experienced meditators report seeing. Though the nature of these visuals varies, meditators agree on one key fact: they’re not just abstractly “pictured”—they literally become visible to the open eye.
Buddhist scholars have been collecting reports of this phenomenon for centuries. In the Theravada tradition, such a visual is called a nimitta, or “sign.” One text, The Path of Purification, explains that a nimitta “appears to some as a star or cluster of gems or a cluster of pearls, […] to others like a long braid string or a wreath of flowers or a puff of smoke, to others like a stretched-out cobweb or a film of cloud or a lotus flower or a chariot wheel.”
Most schools of Buddhism treat nimitta as indicators that a meditator’s practice is maturing, and encourage practitioners to proceed without letting these alluring visuals distract them. However, certain sects of Tantric Hinduism and Vajrayana Buddhism take a more psychedelic approach.
In the practice known as mun mtshams, or “dark retreat,” Tibetan monks lock themselves in a lightless room for weeks or months on end, meditating on a specific image with such intensity that it actually becomes visible as a hallucination. Monks may even meditate on a particular deity until the god appears before them and engages in a full-blown entheogenic dialogue.
How is this possible? While some theorists believe that darkness and concentration cause the brain to pump out psychedelic chemicals like DMT (which we already produce naturally in low concentrations), there’s a much simpler explanation. In a widely documented phenomenon known as the “prisoner's cinema,” many people experience visual hallucinations after just 15 minutes of sensory deprivation, as the brain struggles to translate random neural activity into conscious experience. Stretch those 15 minutes into weeks of minimal sleep and intensive meditation, and even a stone-sober monk may start to see and hear gods in the darkness.
In fact, this is precisely the “a-ha!” that a dark retreat aims to produce. After summoning a god into vivid reality, the meditator deliberately “un-hallucinates” the deity—realizing, in that moment, that everything we see, hear, and feel is constructed by our minds. Neuroscience backs up this conclusion: according to the theory of predictive coding, our brains take in just enough sensory information to make educated guesses about what we’re experiencing, and fill in most of our perceptions from memory. “Normal waking consciousness feels perfectly transparent,” Michael Pollan writes in How to Change Your Mind, “and yet it is less a window on reality than a product of our imaginations — a kind of controlled hallucination.”
While our fears may arise from real experiences, research shows that meditation techniques like eye movement desensitization and reprocessing (EMDR) and body scanning can help us unlearn our emotional triggers and move past traumatic memories. Triumphs like these are only possible because all our perceptions and feelings are, in a sense, hallucinatory.
As the inventor Ray Kurzweil wrote, “We don’t actually see things; we essentially hallucinate them in detail from low-resolution cues.” A Tibetan monk, emerging from the darkness where he’s just vanquished a god, would very likely agree.
Ben Thomas is a journalist and novelist who's lived in 40+ countries. He specializes in telling stories from the frontiers of science, history, culture and the cosmos—and the points where all these fields intersect.