The botany of desire: a plant's-eye view of the world (19 page)

“If I see my grandson rushing to meet me, I feel happy. How do I translate biochemically the objective reality of a grandson rushing toward me into the subjective change in my emotions?” The brain’s cannabinoids could be the missing link.

• • •

So what are the odds that a molecule produced by a flower out in the world—by a weedy plant native to central Asia—would turn out to hold the precise key required to unlock the neurological mechanism governing these aspects of human consciousness? There is something miraculous about such a correspondence between nature and mind, yet it must have a logical explanation. A plant does not go to the expense of making (and continuing to make) such a unique and complex molecule if it doesn’t do the plant some evolutionary good. So why does cannabis produce THC? No one knows for sure, but botanists offer several competing theories, and most of them have nothing to do with getting people high—at least not at the plant’s beginnings.

The purpose of THC could be to protect cannabis plants from ultraviolet radiation; it seems that the higher the altitude at which cannabis grows, the more THC it produces. THC also exhibits antibiotic properties, suggesting a role in protecting cannabis from disease. Last, it’s possible that THC gives the cannabis plant a sophisticated defense against pests. Cannabinoid receptors have been found in animals as primitive as the hydra, and researchers expect to find them in insects. Conceivably, cannabis produces THC to discombobulate the insects (and higher herbivores) that prey on the plant; it might make a bug (or a buck or a rabbit) forget what it’s doing or where in the world it last saw that tasty plant. But whatever THC’s purpose, it’s unlikely that, as Raphael Mechoulam put it, “a plant would produce a compound so that a kid in San Francisco can get high.”

Or is it? Robert Connell Clarke, the marijuana botanist I met in Amsterdam, doesn’t think that notion is quite as far-fetched as Mechoulam makes it sound. He finds most of the defense theories inadequate and concludes that “the most obvious evolutionary advantage THC conferred on
Cannabis
was the psychoactive properties, which attracted human attention and caused the plant to be spread around the world.”

Of course, Mechoulam and Clarke could both be right. Whatever THC’s original purpose may have been, as soon as a certain primate with a gift for experiment and horticulture stumbled on its psychoactive properties, the plant’s evolution embarked on a new trajectory, guided from then on by that primate and his desires. The cannabis flowers that gave humans the most pleasure, or strongest medicine, were now the ones that produced the most offspring. What may have started out as a biochemical accident became the plant’s coevolutionary destiny, or at least
one
of its destinies, under domestication.

Ma,
the ancient Chinese character for “hemp,” depicts a male and a female plant under a roof—cannabis inside the house of human culture. Cannabis was one of the earliest plants to be domesticated (probably for fiber first, then later as a drug); it has been coevolving with humankind for more than ten thousand years, to the point where the aboriginal form of the plant may no longer exist. By now cannabis is as much the product of human desire as a Bourbon rose, and we have scant idea what the plant might have been like before it linked its destiny to our own.

But what is so unusual about cannabis’s coevolution (compared to that of the rose, say, or the apple) is that it followed two such divergent paths down to our time, each reflecting the influence of a completely different human desire. Along the first path (which appears to have begun in ancient China and moved west toward northern Europe, then on to the Americas), the plant was selected by people for the strength and length of its fibers. (Up until the last century, hemp was one of humankind’s main sources of paper and cloth.) Along the other path (which began somewhere in central Asia and moved down through India, then into Africa, and from there across to the Americas with the slaves and up to Europe with Napoleon’s army), cannabis was selected for its psychoactive and medicinal powers. Ten thousand years later, hemp and cannabis are as different as night and day: hemp produces negligible amounts of THC and cannabis a worthless fiber. (In the eyes of the U.S. government, however, there is still only one plant, so that the taboo on the drug plant has, pointlessly, doomed the fiber.) It is hard to conceive of a domesticated plant more plastic than cannabis, a single species answering to two such different desires, the first more or less spiritual in nature and the other, quite literally, material.

• • •

The scientists I talked to had a lot to say about the descent and biochemistry of cannabis, but about the plant’s effects on our experience of consciousness they were all but silent. What I wanted to know is, What exactly does it mean, biologically, to say a person is “high”? When I put this question to Allyn Howlett, her answer consisted of two rather parched words: “cognitive dysfunction.”
Cognitive dysfunction?
Okay, but isn’t that a little like saying that having sex elevates one’s pulse? It’s perfectly true as far as it goes, but it doesn’t get you any closer to the heart of the matter—or to the desire. John Morgan, a pharmacologist who has written widely about marijuana, points out that “we don’t yet understand consciousness scientifically, so how can we hope to explain changes in consciousness scientifically?” Mechoulam replied to my questions about what it means biochemically to be high simply by saying, “I am afraid we have to leave these questions still to the poets.”

So there it seemed the neuroscientists had stranded me, all on my unscientific own with a dime bag and the dubious company of poets such as Allen Ginsberg and Charles Baudelaire, Fitz Hugh Ludlow and (yikes!) Carl Sagan—but Carl Sagan wearing his goofiest nonscientific hat. You see, I’d discovered that in 1971 Sagan had anonymously published an earnest, marvelous account of his experiences with pot, which he credited with “devastating insights” about the nature of life.
*

Yet as I proceeded with my literary and phenomenological investigations of the pot experience, I soon realized I had gotten something valuable from the scientists after all. They had inadvertently pointed me in the direction of a deeper understanding of what it is that cannabis does to human consciousness and what, possibly, it has to teach us about it. In fact, Howlett was probably right, if inelegant, in her simple formulation, because I’ve come to think that a “cognitive dysfunction” of a very special kind does in fact lie at the heart of it. Let me try to explain.

The scientists I spoke to were unanimous in citing short-term memory loss as one of the key neurological effects of the cannabinoids. In their own way, so were the “poets” who tried to describe the experience of cannabis intoxication. All talk about the difficulty of reconstructing what happened mere seconds ago and what a Herculean challenge it becomes to follow the thread of a conversation (or a passage of prose) when one’s short-term memory isn’t operating normally.

Yet the scientists said that the THC in cannabis is only mimicking the actions of the brain’s own cannabinoids. What a curious thing this is for a brain to do, to manufacture a chemical that interferes with its own ability to make memories—and not just

memories of pain, either. So I e-mailed Raphael Mechoulam to ask him why he thought the brain might secrete a chemical that has such an undesirable effect.

Don’t be so sure that forgetting is undesirable, he suggested. “Do you really want to remember all the faces you saw on the New York City subway this morning?”

Mechoulam’s somewhat oblique comment helped me begin to appreciate that forgetting is vastly underrated as a mental operation—indeed, that it
is
a mental operation, rather than, as I’d always assumed, strictly the breakdown of one. Yes, forgetting can be a curse, especially as we age. But forgetting is also one of the more important things healthy brains do, almost as important as remembering. Think how quickly the sheer volume and multiplicity of sensory information we receive every waking minute would overwhelm our consciousness if we couldn’t quickly forget a great deal more of it than we remember.

At any given moment, my senses present to my consciousness—this perceiving “I”—a blizzard of data no human mind can completely absorb. To illustrate the point, let me try to capture here a few drops of this perceptual cataract, preserve one cross section of the routinely forgotten. Right now my eyes, even without moving, offer the following: directly in front of me, the words I’m typing on a computer screen along with its blue background and tumble of icons. Peripherally, there’s the blond wood grain of my desk, a mouse pad (printed with words and images), a CD spinning red in its little window, two bookshelves crammed with a couple of dozen spines I could easily read but don’t, a gray plastic heater grate, a blue folder (entitled “Pot clips”) stuck into a standing file at an annoying angle, two hands with an unspecified number of flying fingers (Band-Aid on one hand, glint of gold on the other), one jeans-clad lap, two green-sweatered wrists, a window (its green muntins framing a boulder with lichens, dozens of trees, hundreds of branches, millions of leaves), and, drawing a soft border around 90 percent of this visual field, the metal frames of my eyeglasses.

And that’s just my eyes. My sense of touch meanwhile presents to my attention a low background drone of shoulder ache, a slight burning sensation in the tip of my right middle finger (where it was cut the other day), and the cool rush of air through my nostrils. Taste? Black tea and bergamot (Earl Grey), slightly briny breakfast residue on tongue (smoked salmon). Soundtrack: Red Hot Chili Peppers in the foreground, backed by heater whoosh on the right, computer cooling fan whoosh on the lower left, mouse clicks, keyboard clatter, creak-crack of those knucklelike things deep in the neck when I cant my head to one side; and then, outside, a scatter of birdsong, methodical drips on the roof, and the slow sky tear of a propeller plane. Smell: Lemon Pledge, mixed with woodsy damp. I won’t even try to catalog the numberless errant thoughts presently nipping around the writing of this paragraph like a flittering school of fish. (Or maybe I will: second thoughts and misgivings arriving in waves, shoving crowds of alternative words and grammatical constructions, shimmering lunch options, small black holes of consciousness from which I try to fish out metaphors, a clamoring handful of to-dos, a spongy awareness of the time till lunch, and so on, and so on.)

“If we could hear the squirrel’s heartbeat, the sound of the grass growing, we should die of that roar,” George Eliot once wrote. Our mental health depends on a mechanism for editing the moment-by-moment ocean of sensory data flowing into our consciousness down to a manageable trickle of the noticed and remembered. The cannabinoid network appears to be part of that mechanism, vigilantly sifting the vast chaff of sense impression from the kernels of perception we need to remember if we’re to get through the day and get done what needs to be done.
*
Much depends on forgetting.

The THC in marijuana and the brain’s endogenous cannabinoids work in much the same way, but THC is far stronger and more persistent than anandamide, which, like most neurotransmitters, is designed to break down very soon after its release. (Chocolate, of all things, seems to slow this process, which might account for its own subtle mood-altering properties.) What this suggests is that smoking marijuana may overstimulate the brain’s built-in forgetting faculty, exaggerating its normal operations.

This is no small thing. Indeed, I would venture that, more than any other single quality, it is the relentless moment-by-moment forgetting, this draining of the pool of sense impression almost as quickly as it fills, that gives the experience of consciousness under marijuana its peculiar texture. It helps account for the sharpening of sensory perceptions, for the aura of profundity in which cannabis bathes the most ordinary insights, and, perhaps most important of all, for the sense that time has slowed or even stopped. For it is only by forgetting that we ever really drop the thread of time and approach the experience of living in the present moment, so elusive in ordinary hours. And the wonder of
that
experience, perhaps more than any other, seems to be at the very heart of the human desire to change consciousness, whether by means of drugs or any other technique.

• • •

“Consider the cattle, grazing as they pass you by,” Friedrich Nietzsche begins a brilliant, somewhat eccentric 1876 essay he called “The Uses and Disadvantages of History for Life.” “They do not know what is meant by yesterday or today, they leap about, eat, rest, digest, leap about again, and so from morn till night and from day to day, fettered to the moment and its pleasure or displeasure, and thus neither melancholy nor bored. . . .

“A human being may well ask an animal: ‘Why do you not speak to me of your happiness but only stand and gaze at me?’ The animal would like to answer, and say, ‘The reason is I always forget what I was going to say’—but then he forgot this answer too, and stayed silent.”

The first part of Nietzsche’s essay is a moving and occasionally hilarious paean to the virtues of forgetting, which he maintains is a prerequisite to human happiness, mental health, and action. Without dismissing the value of memory or history, he argues (much like Emerson and Thoreau) that we spend altogether too much of our energy laboring in the shadows of the past—under the stultifying weight of convention, precedent, received wisdom, and neurosis. Like the American transcendentalists, Nietzsche believes that our personal and collective inheritance stands in the way of our enjoyment of life and accomplishment of anything original.

“Cheerfulness, the good conscience, the joyful deed, confidence in the future—all of them depend . . . on one’s being just as able to forget at the right time as to remember.” He admonishes us to cast off “the great and ever-greater pressure of what is past” and live instead rather more like the child (or the cow) that “plays in blissful blindness between the hedges of past and future.” Nietzsche acknowledges that there are perils to inhabiting the present (one is liable to “falsely suppose all his experiences are original to him”), but any loss in knowingness or sophistication is more than made up for by the gain in vigor.