by Mary Roach
Model-dependent realism applies not only to scientific models but also to the conscious and subconscious mental models we all create to interpret and understand the everyday world. For example, the human brain processes crude data from the optic nerve, combining input from both eyes, enhancing the resolution, and filling in gaps such as the one in the retina's blind spot. Moreover, it creates the impression of three-dimensional space from the retina's two-dimensional data. When you see a chair, you have merely used the light scattered by the chair to build a mental image or model of the chair. The brain is so good at model-building that if people are fitted with glasses that turn the images in their eyes upside down, their brains change the model so that they again see things the right way up—hopefully before they try to sit down.
Glimpses of the Deep Theory
In the quest to discover the ultimate laws of physics, no approach has raised higher hopes—or more controversy—than string theory. String theory was first proposed in the 1970s as an attempt to unify all the forces of nature into one coherent framework and, in particular, to bring the force of gravity into the domain of quantum physics. By the early 1990s, however, physicists discovered that string theory suffers from an awkward issue: there are five different string theories. For those advocating that string theory was the unique theory of everything, this was quite an embarrassment. In the mid-1990s researchers started discovering that these different theories—and yet another theory called supergravity—actually describe the same phenomena, giving them some hope that they would amount eventually to a unified theory. The theories are indeed related by what physicists call dualities, which are like mathematical dictionaries for translating concepts back and forth. But, alas, each theory is a good description of phenomena only under a certain range of conditions—for example, at low energies. None can describe every aspect of the universe.
String theorists are now convinced that the five different string theories are just different approximations to a more fundamental theory called M-theory. (No one seems to know what the "M" stands for. It may be "master," "miracle," or "mystery," or all three.) People are still trying to decipher the nature of M-theory, but it seems that the traditional expectation of a single theory of nature may be untenable and that to describe the universe we must employ different theories in different situations. Thus, M-theory is not a theory in the usual sense but a network of theories. It is a bit like a map. To faithfully represent the entire Earth on a flat surface, one has to use a collection of maps, each of which covers a limited region. The maps overlap one another, and where they do, they show the same landscape. Similarly, the different theories in the M-theory family may look very different, but they can all be regarded as versions of the same underlying theory, and they all predict the same phenomena where they overlap, but none works well in all situations.
Whenever we develop a model of the world and find it to be successful, we tend to attribute to the model the quality of reality or absolute truth. But M-theory, like the goldfish example, shows that the same physical situation can be modeled in different ways, each employing different fundamental elements and concepts. It might be that to describe the universe we have to employ different theories in different situations. Each theory may have its own version of reality, but according to model-dependent realism, that diversity is acceptable, and none of the versions can be said to be more real than any other. It is not the physicist's traditional expectation for a theory of nature, nor does it correspond to our everyday idea of reality. But it might be the way of the universe.
Spectral Light
Amy Irvine
FROM Orion
IN THE DEAD of night the human brain is most capable of distillation—of boiling things down to basic black and white. Smoke means fire. Breaking glass signals intrusion. From an evolutionary standpoint, this kind of rudimentary thought process might be a most valuable survival skill—the kind that allows a body to respond to threats even in a state of half-sleep. My husband, Herb, is a lawyer, the kind of man who has been trained to think before he acts— to examine all angles and consider complexities. But at three A.M. on an uncharacteristically cold and moonless night in late spring, even he is reduced. And through that reduction, he would come to see how things that lurk too starkly, even at opposing ends of the spectrum, can shift. As if fundamentals could be that supple. As if values—like the presence of all colors in relation to the sheer absence of them—could be so pliant. As if the natural order of things—like the age-old relationship between predator and prey— could flex into a new arrangement altogether.
The dogs would start it. Their frenzied barks, their teeth gnashing against the glass of the back door, would draw my husband out of bed and into his jeans in a single motion. In the mudroom he would stumble through a sea of writhing canines, pull on his boots with one hand and turn the knob with the other. Two aging Aussies and a half-blind border collie mix would spill out into the dark yard and charge toward the goat pen. They would make it halfway before stopping dead in their tracks and high-tailing it back to the porch. Herb would hear the screams then, the desperate cries for help. He would fumble in the doorway for the porch light, two-stepping with the returning dogs, and there his sleep-riddled mind would already be drawing conclusions so swiftly it would feel, he would say later, like pure instinct.
And here I should point out that my husband, despite his profession, is a man who could have been born into the Paleolithic—the kind of guy who has built a life sustained by wildness more than any other element. After college Herb left Michigan for the West and never looked back. On the other side of the Continental Divide he found the kind of unfettered topography that he needed—for he's a man who is happiest when ambling over great stretches of soil or stone. He loves the basics, the way they ignite his senses: The procurement of food, shelter, warmth. The silky curves of women, skylines, rivers. Then there is his deeply held belief that he is a sort of Dr. Dolittle, and indeed, I have been witness to his extraordinary ability to communicate with animals. Domestic or untamed, creatures of all sorts seem to enter quickly into some kind of understanding with him.
It is this latter quality that explains why my husband's guns have never been loaded—despite the fact that we have made our home in one of the more wild parts of the West, where black bears, mountain lions, bobcats, and elk are as common as livestock. Where large tracts of untrammeled public land still eclipse both alfalfa fields and subdivisions of "ranchettes." Herb had stored in various places a .22 Smith & Wesson six-shooter, a 12-gauge shotgun, and three rifles in .22, .30-06, and 7mm magnum calibers—an inheritance from his grandfather, who had been an avid hunter in both the Great Lakes region and in Africa. All but the .22s had lain in their cases since his grandfather had died nearly eleven years prior—and those two firearms had only been used to shoot beer cans off fence posts on the occasional Sunday afternoon. Looking back, I think we both took a certain pride—and a smug one at that—in having no need for guns in what is largely a gun-toting community of roughneck ranchers, folks who let loose bullets daily on coyotes and prairie dogs.
So it is mind-boggling that Herb would conclude as he did on that night. Call it a natural impulse, or call it one of the ill effects of living in a culture steeped in sensational news and violent movies, but his mind instantly crafted the assumption that the hair-raising cries coming across the dark yard were of human origin. Somehow, he decided—in our critter-laden outback of a neighborhood that sits seven miles from a tiny, low-crime kind of town—that some heinous, unspeakable assault was being committed by one deranged human upon another. And as he charged away from the now-cowed dogs into the colorless void that lay beyond the porch light's glare, his brain illuminated with one white, shining thought: This is what the world has come to. Standing empty-handed in the inkwell of night, he was ready to face squarely some malevolence in his own species.
Herb turned, detouring away from the pen and into an adjoining shed, where he flipped on the light and took q
uick inventory of several of his grandfather's firearms. He then knelt to rummage for ammunition in a random collection of boxes. This took some doing—my husband is not the most organized of men. And in the process he failed to hear the intruder climb back over the imposingly tall fence that contained the goats and circle around the shed. It was only as he realized that the cartridges that matched these particular firearms were elsewhere that he heard the padding approach behind him. He stood and turned. On the threshold, only four feet away, stood a three-hundred-pound black bear.
Our daughter, Ruby, and I were not there that night—and in hindsight, as well as in the spirit of thinking so fundamentally about things, I can't decide if that was a good or a bad thing. Would our presence have changed in any way Herb's course of action, or the bear's? Would the dogs have been more aggressive? And what might I have done to alter the outcome? Through countless replays of the situation, Herb and I would be reminded that variables come in many hues, and each one has the potential to change the overall effect—the way Warhol's varied silk-screens of Marilyn Monroe changed the essence of the subject simply by changing the colors. Of course we also have to consider that we can only see things through the lens we were born peering into—while other species are able to perceive things entirely invisible to the human eye.
The bear stalled on the threshold for a moment, and my husband stalled briefly too, before realizing he could not possibly summon a single word of conversation with what stood before him. For the first time in his life, Herb was tongue-tied. When he finally spoke (Yo, dude, unbelievably), the bear fixed his gaze on him and took a step forward. Fortunately, Herb had been training to bench-press 315 pounds in honor of his fortieth birthday, and so, rather than continuing the conversation, he lunged at the half-open door and heaved his body against it—effectively shoving the bear back outside. The bear stood there for a few minutes, then shuffled across the driveway and into the woods.
Not man, but beast. Of course. Herb's mind quickly reconfigured to what should have been his first impression all along: big animal with teeth and claws has found easy food in what had been a rather unforgiving emergence from the winter den—the late frosts having nipped springtime staples such as young forbs and grasses. Meanwhile, our daughter's pet goat, a white, bottle-fed Nubian named Dora the Explorer, was still screaming. And at last Herb recognized the wails as hers.
Curiously, the dogs remained on the porch, not uttering a sound. When Herb exited the shed and headed for the house, he made note of the quiet, for three dogs barking in unison has always been enough to keep wild animals at bay. He hadn't even made it ten feet from the shed when the bear reemerged from the woods. Herb scrambled back inside and waited. When he opened the door a second time, the bear stepped out again and came right at him. The two repeated this pas de deux over the course of an hour. It was sometime during those sixty minutes that the goat ceased her cries.
Perhaps the reason Herb failed to grasp the situation more quickly was the same reason our dogs were so quiet: they were stymied by the bear's unlikely behavior, its seemingly sheer fearlessness, its clearly predatory intent—for these are not attributes we see in the wildlife on our mesa. Here, seated between the 14,000-foot peaks of the San Juan Mountains and the red canyons and rivers of the Colorado Plateau, there is still a great deal of food and space for humans and animals alike. Unlike their cousins trying to eke out a wild lifestyle within the slim margins of the nation's national parks, and unlike those poor ursines who have had the misfortune of claiming turf near dense populations of humanity, our black bears have had the luxury of keeping almost exclusively to themselves.
There were explanations: Perhaps the bear was sick. Or maybe it was a juvenile orphaned before learning how to acquire food properly. But it's also possible that this bear was part of an escalating and global trend—for some biologists say animals everywhere appear to be changing in new and unsettling ways. One recent study concluded that human impacts are forcing animals to evolve at a pace three hundred times faster than they would naturally. And there is evidence to support that the traits affected are not only size and reproductive capacities but behavior too. David Baron, the author of The Beast in the Garden: A Modern Parable of Man and Nature, contends that some regional trends in cougar attacks are "upward and exponential." Boulder, Colorado, is his prime example—where an environmentally minded populace has sought to live closer to nature by building homes on the "edge," the transitional area between forest highlands and desert plains. A zone where deer feed. And where lions hunt. The equation has been disastrous for everyone. The deer overpopulated in backyards while the big cats began stalking, mauling—and sometimes killing—a relatively significant number of household pets and humans. Of course the offending cats were destroyed. But here's the kicker: whenever a guilty lion was removed from an area, others quickly moved in—only to exhibit the same new tactics.
Add to this global scenario of changing behavior the ill effects of climate change. Barren-ground grizzlies, for example, have faced a diminished supply of coastal-plain plants—a food source that is dwindling in a warming Arctic. Without this essential nutritional source, the bears have been forced to alter their foraging and feeding habits, and some have become malnourished in the process. One such grizzly recently killed and consumed two experienced Alaskan-bush backpackers who, in the opinion of the investigating officer, "did most everything right" in their efforts to deter bears from their camp.
Given this new context, it is probably inappropriate to say that such predator behavior is aberrant; rather, these animals are adapting fittingly to a drastically altered environment. There's irony here: the more humans coif the natural world to our liking, the more we push out into the last wild places for recreation and real estate, the more we are finding ourselves back on the food chain—as a menu item.
Herb and I are complicit in this twenty-first-century showdown between wildlife and people; the five-acre parcel we purchased for a home site had been a bull pasture until the rancher subdivided it to subsidize his retirement. The east half of the property is hemmed in by neighboring pastures of grass and alfalfa—a scene utterly bucolic, punctuated by the brays of livestock. The backside of the property is altogether different. A woodland of oak, piñon, and juniper slopes down to a lush creek bottom lined with cottonwoods, wild iris, and tall grasses. The draw carved by the creek begins high on the forested uplands to our south and serves as a natural corridor for wild ungulates that move between desert lowlands in winter and high mountain meadows in summer. The predators—black bear, mountain lion, bobcat, and coyote—all follow suit. Our 800-square-foot house sits smack dab on the dividing line of these two worlds—and depending on which way you turn when you walk out the door, the rules for how to behave, what to watch for, can be very different.
Ruby and I return home the day after the bear's visit, and already Herb's story has spread across the mesa like a runaway ditch fire. Like so many small towns in the West, we're a mixed group here—a blend of traditional rural folk and transplants who have fled cities and suburbs alike. For weeks afterward, I am reminded of the dichotomy between the two camps; each time I am asked to re-count the story on Herb's behalf, I receive one of two pat responses.
The New West: Did he try and talk to the bear? Did he project peaceful energy?
The Old West: I hope he shot the son of a bitch.
To each individual, I nod. Yes, he did try to communicate. And yes, he shot it.
The double affirmative isn't duplicitous. In terms of philosophy and aesthetic sensibilities, it is easy to side with the New West's romantic notions about preserving natural landscapes and living in and among wildlife. But the old-timers have a point. They largely blame the newcomers, who flock to places like Telluride (a re-sort town thirty-four miles to the east), where predominantly well-heeled, left-leaning residents supported the Colorado Division of Wildlife's termination of the spring bear hunt. The town's abundant PETA enthusiasts and Humane Society donors also ap
plauded the prohibition of hounds for the remaining autumn hunt—deeming it a cruel example of unfair chase. In response, our enclave's more traditional, rural crowd could be heard grumbling, Now them bears are thick as thieves...
It's true that resort towns in the West tend to have the biggest bear problems. Garbage cans, greasy barbecues, and bowls of pet food get left out by individuals who tend to be rather naive about wildlife. When the bear comes sniffing for easy extra calories (in late summer a black bear must consume 200,000 calories a day in order to survive winter hibernation), such folks snap pictures when they should be clanging pans or throwing rocks—actions which, with a healthy, unconditioned bear, are almost always enough to scare it off. For minor first offenses, wildlife officers will tranquilize a bear, punch an ID tag through its ear, and relocate the animal—to places with more open country, places like my neighborhood, where they become our problem (and perhaps this was the case with Herb's visitor). But in severe cases, or repeat offenses, the bears are put down with a big-caliber bullet—executions that are all on the taxpayer's dime.
Bear stories like Herb's linger on our tongues, in our imaginations, like erotica. They are titillating precisely because they are the closest that most of us come to igniting the ancient physiological and psychological tinder of the predator-prey relationship that lies dormant in the human body. (Come get me, Mommy! I see the glowing embers in my daughter's eyes, hear the quickening of her breath, when she asks me to chase her.) And perhaps this is why the cause to protect North America's predators is so feverish, and why it is equaled in pitch only by the efforts to exterminate them. Each side is glaring, garish even, in its shriek of righteousness—and so it is with bears the way it is with everything else: we respond from a black-and-white paradigm; the potent dualities of us versus them resound with a faint, prehistoric echo. Instead of man against weather, or man against beast, though, it's Republicans vs. Democrats, tree-huggers vs. wise-users, Buddhists vs. Bible thumpers. The appeal of such binary thinking is that we are able to name not only who we are but also what we are not. We draw the dividing line like a firebreak, and it holds back the advancing enemy while we retreat to safer ground.