an excerpt from
Fire in the Mind: Science, Faith, and the Search for Order
by George Johnson
Chapter 4. The Demonology of Information
In the beginning, the main route connecting Santa Fe to the rest of the known universe was the Camino Real, the royal highway that ran up from Mexico City, meeting the Rio Grande at El Paso and following it northward through Albuquerque, Santa Fe, and on to the hinterlands of New Spain. Today the American portion of the Camino Real has been replaced by Interstate 25, but the scenery along the route remains pretty much the same. Those who fly into Albuquerque International Airport and drive north for a scientific conference in Santa Fe or Los Alamos pass through a stark landscape very much like that the Spanish conquistadores saw.
To the east, as one leaves the suburban sprawl of the Albuquerque metropolitan area, the Sandia mountains rise nearly 6,000 feet above the already mile-high terrain, exposing a rocky facade so fractured and so sheer it looks as though half the mountain had been sliced away. In a sense that is what happened. The Sandias are an example of what geologists call a fault-block mountain. Like the Sangre de Cristos they were squeezed from the earth when two plates collided, but in the case of the Sandias one side collapsed; instead of a slope, the western face of the mountain is a treeless, almost vertical expanse of steep granite walls. The most prominent of these is the Shield, so formidible, the guidebooks say, that some of its more onerous ascents can take days of hard climbing, the nights spent roped to the cliff like a tent worm, trying to fall asleep on vertical ground.
To the west, beyond a line of dormant volcanoes, one can barely see Mount Taylor, a jagged blue bump on the horizon that was named after General Zachary Taylor, after he took this land from the Mexicans in the War of 1846. The Mexicans, and the Spanish before them, called the mountain Cebolleta, little onion. They took it from the Navajos, who still call it Turquoise Mountain and consider it the southern border of their universe and the home of Monster Slayer, one of the legendary Hero Twins who fought against the evils of the earth. Drive west from Albuquerque on Interstate 40, old Route 66, and just before Grants, a mining town that in better times billed itself as the Uranium Capital of the United States, you cross over the petrified bubbles of the Malpais (bad land) lava flow; the Navajos say it is the dried blood of Ye-itsa, one of Monster Slayer's victims. Ye-itsa's head can be found to the north in the form of an old volcanic plug with sloping shoulders that the Spanish named Cabezón Peak. (Cabeza means head and a cabezón is one that is particularly big and ugly.) Ye-itsa's bones (the geologists say they are petrified trees) lie as far east as Albuquerque. Though Ye-itsa was killed and turned to stone, some of the monsters survived, the legend goes. Demons called hunger, greed, filth, and old age still stalk the land.
The Pueblo Indians included the Navajos among the monsters and still remember the stories of their raids on the adobe villages that lie between Albuquerque and Santa Fe along the Rio Grande -- Sandia Pueblo, Santa Ana, Santo Domingo, San Felipe, Cochiti, little worlds with their own languages and, like the Tewa pueblos to the north, their own quartets of magic mountains marking off their personal universes. The landscape on this part of the journey is like nothing else on earth. Far to the west the Jemez mountains reach toward the river with fingers of lava, hardened into the black, flat mesas that, to use another metaphor, look like frozen breakers of stone. The turnoff to San Felipe, a hive of adobe houses shaded with cottonwoods hunched against the base of one of the larger mesas, marks the halfway point of the drive to Santa Fe. A few miles later, just after the highway crosses the dry arroyo of the Galisteo River, a steep volcanic wall looms into view. The Spanish called it La Bajada, which means "the descent," though when driving up from Albuquerque it is quite the opposite, a thousand-foot rise that divides the lower country of Southern New Mexico from the highlands of the north. Until this point the highway has been cutting across what the Spanish cartographers called Rio Abajo, lower river, the part of the northern kingdom that lay closest to Mexico City. In those days of horses and wagons, La Bajada was known for the treachery of its hairpin turns -- the price one paid for entering another realm: Rio Arriba, upper river, the vast, barely explored region that extended north of La Bajada and then off the top of the maps.
Perhaps it is fitting that La Bajada was named from the Rio Arribans' point of view. Sitting in their perch 7,000 feet above sea level, the people of Santa Fe and beyond literally and sometimes figuratively looked down on their neighbors in Rio Abajo. Except for a gradual rise to reach the top of the La Bajada hump, it was a 2,000-foot slide from Santa Fe to Albuquerque. The change wasn't simply one of geography. La Bajada was, and is, a psychological and a cultural divide. Though Southern New Mexico has its share of mountains, it is largely a flat, desert land whose subtle beauty requires the heart and eye of a connoisseur. There is nothing subtle about the topography of Northern New Mexico. Once you ascend La Bajada, with the Sangre de Cristos looming straight in front of you and the carved symmetrical volcanoes rising from either side of the highway, Rio Arriba opens up all around. You know you are in another country, where even the light seems changed.
It wasn't easy, going between the land of the familiar and the land of the strange. Wagon drivers coming down La Bajada often had to brace their wheels with rocks to keep from succumbing to the force called gravity. Cars heading the other way sometimes had to back up the hill, reverse gear providing them with more leverage, as their boiling radiators protested against the heat. Today the endless turns have been straightened into a more gradual ascent; cars and trucks barely slow down as they surmount the divide. But they are still bound by the same laws of physics that held sway in the conquistadores' time. Then and now it takes energy to cross the divide.
In May 1989 some three dozen scientists, mostly from the United States but a few from as far away as Germany, Britain, France, Israel, and Japan, flew into Albuquerque and boarded rental cars and shuttle buses for the journey up the Camino Real. Skirting the edges of the pueblo universes, they ascended La Bajada arriving in Santa Fe for a conference sponsored by the Santa Fe Institute and held in the spectacular setting provided by St. John's College, which sits at a confluence of arroyos that cut through the foothills of the Sangre de Cristo mountains. Hike three miles up the canyons from St. John's and you reach Atalaya Peak. Atalaya means watch tower, and if you stand on its heights and look down on Santa Fe and across to Los Alamos you will be seeing what may be the world's largest concentration of scientists (granted, there aren't many) working in a new field called the physics of information, which sits at the boundary where mind and nature, subject and object, seem to collide.
In some ways, St. John's seemed an incongruous setting for a conference on so revolutionary a subject as information and physics. The school is known for its classical curriculum: students learn physics by starting with the pre-Socratics then moving on to the more recent ideas of Plato and Aristotle. The physicists and mathematicians were coming to St. John's to discuss ideas at the very edge of twentieth-century science. They were responding to a manifesto with the intriguing title "Complexity, Entropy and the Physics of Information," which had been dispatched by Wojciech H. Zurek, a Polish-born physicist who works at the Los Alamos National Laboratory's Theoretical Astrophysics Group.
In building a tower of abstraction, one must start with a foundation, those things that are taken as given: mass, energy, space, time; everything else can then be defined in terms of these fundamentals. But gradually over the last half century some scientists -- and Zurek was among the most adamant -- had come to believe that another basic ingredient was necessary to make sense of the universe: information. "The specter of information is haunting the sciences," his manifesto began. There is a "border territory," he believed, where information, physics, complexity, quantum theory, and computation meet. So in another way, St. John's wasn't so strange a setting for the conference after all. What Zurek and his colleagues had in mind was a return to basics, a rethinking of reality's pillars as thorough as any undertaken by Thales, who thought all was made of water, or Heraclitus, who thought all was made of fire.
Most of us are used to thinking of information as secondary, not fundamental, something that is made from matter and energy. Whether we are thinking of petroglyphs carved in a cliff or the electromagnetic waves beaming from the transmitters on Sandia Crest, information seems like an artifact, a human invention. We impose pattern on matter and energy and use it to signal our fellow humans. Though information is used to describe the universe, it is not commonly thought of as being part of the universe itself. But to many of those at the Santa Fe conference, the world just didn't make sense unless information was admitted into the pantheon, on an equal footing with mass and energy. A few went so far as to argue that information may be the most fundamental of all; that mass and energy could somehow be derived from information.
There was, first of all, the mysterious connection that seemed to exist between information, energy, and entropy, the amount of disorder in a system. We learn in school that, left on its own, any closed system becomes more and more disorderly; its entropy increases. It is because of this fact, embodied in the Second Law of Thermodynamics, that neat geological strata become gnarled into formless Precambrian rock. The planar geometry of an Anasazi adobe village melts until it is barely distinguishable from the surrounding hills. Along the way, information is lost. Information can be thought of as a measurement of distinctions, the simplest being 1 or 0, the presence or absence of a certain quality. Thus there is more information in something that is orderly than in a homogeneous, undifferentiated mess.
On the other hand, by gathering and processing information, we can create order -- we can take the matter and energy of our world and arrange it into songs, civilizations, fragile eddies in the entropic tide. Using our powers as information processors, we can find unlikely structures that already exist -- water trapped in a mountain lake, carbon molecules strung in a volatile chain, protons and neutrons stacked into a precarious nuclear sphere. And then we simply let them follow the path of least resistance. As they topple and move down the hill from order to disorder, we can extract work by harnessing the entropic flow. The nucleus disintegrates, the bonds of the carbon atoms break, the water flows from its pool to the formless sea. Entropy increases, information is lost, but the energy released in the process can be tapped to build new structures, to create information, though all our creations must eventually succumb to the Second Law.
No wonder the mind craves patterns. It is the ability to find order in the world that allows us to make use of its resources. For many scientists this would be reason enough to believe that information is fundamental. But, going beyond the laws of thermodynamics, some believe information plays an even deeper role. According to some interpretations of quantum theory put together by Zurek and his circle, without information there would be no resources to exploit and no one to exploit them; there would be nothing that resembled what we call the real world. The mathematics used to describe the subatomic realm tells us that, left to its own devices, an electron lacks the very attributes that we, on our macroscopic plateau, consider the very hallmark of existence -- a definite position in time and space. It exists, we are told, as a probability wave, a superposition of all the possible trajectories that takes on substance only when it is measured, when, as it is often put, an observer collapses the probability wave. How this transformation occurs is one of the deepest mysteries of physics, the so-called measurement problem: How does the rock-solid classical world, in which things occupy definite positions in space and time, crystallize from the quantum haze? In the past, quantum theory has often been embraced by those who would elevate subjectivity over objectivity, championing a mystical world view in which consciousness brings the universe into being. By making information fundamental, Zurek and some of his colleagues hoped to demystify quantum theory. For what is an observation but a gathering of information? And if information is fundamental, it exists as surely as does matter and energy, without the need of conscious beings. The quantum wave might collapse not because it was beheld by a mind but simply because information flowed from one place to another in the subatomic realm.
Of course it is easy to be fooled by our own metaphors, becoming so dazzled by the concepts we invent that we can see the world only through their glare. In the nineteenth century, entropy and the laws of thermodynamics were invented to better understand the steam engine and how to make it as efficient as nature would allow. Any closed system, sealed off from its environment, would inevitably march from order to disorder. Soon scientists and philosophers were applying these new mental tools to the universe itself, declaring that, as the most closed of closed systems -- what could possibly be outside of it? -- the universe was marching inevitably to thermodynamic death, a state of equilibrium, lifeless, unstructured, random. In the twentieth century, information theory was invented to help engineers make electronic communications channels as efficient as possible. And before we knew it, people were speaking of information as real, a few going so far as to imagine that we live in a universe of computation, created from the shuffling of bits.
One of the challenges implicit in Zurek's manifesto was to find new ways to think about whether computation -- and therefore information -- is natural or artificial. The computers we have built over the years have been crafted from macroscopic parts; first gears, then vacuum tubes, then transistors, and now chips inscribed with thousands of transistors that get smaller and more densely packed every year. We stamp our designs on nature's designs; circuitry onto silicon lattices. But the finer the blueprints of our artifices, the more they begin to clash with the physics underneath. Quantum randomness scrambles our neat choreography of 1s and 0s. But perhaps as engineers reach tinier and tinier scales they can somehow exploit the natural behavior of atoms to make their machines more efficient, bridging the divide between the circuitry we design and the "circuitry" of nature. An atom with an electron that could be in one of two states might naturally be thought of as a register containing a 1 or a 0. (Is that any stranger than thinking of it as a tiny solar system?) How thin can we make this gap between the laws of computation and the laws of physics? Where will the shrinking bottom out? If computation can take place only down to a certain scale, requiring components made up of many, many molecules, then perhaps information is simply an artifice, secondary to the laws of physics, a pattern imposed by people as they struggle to describe the world. But if single molecules or even atoms can be said to somehow process information, then maybe computation is as fundamental as what we think of as the laws of physics. Like mass and energy, information would be irreducible, at the roots of creation.
For many of the people who gathered in Santa Fe to talk about information, thermodynamics, and quantum theory, this would be the first of many visits to Northern New Mexico. Another conference followed a year later, this one at the Santa Fe Institute, which was then housed in an old convent among the galleries and adobe houses on Canyon Road. In a way, though, the first conference never really ended. Over the years, the physics of information group Zurek started at the Santa Fe Institute has attracted a changing cast of visitors. Rolf Landauer and Charles Bennett, two of the first people to study the physics of information, visit frequently from the IBM Thomas J. Watson Research Center in New York. From his house in Tesuque, a rural village that provides refuge for those who find even Santa Fe's slow pace too frenetic, Murray Gell-Mann and his frequent guest, James Hartle of the University of California at Santa Barbara, began an attempt to find a way to use information to make sense of quantum cosmology, in which the whole universe can be thought of as a continuously collapsing quantum probability wave.
As one listened to their lectures, read their papers, and spoke to them privately, at dinner or in hikes through the mountains, it was hard not to be struck by hints of an even deeper purpose to their travails. The physicists at Santa Fe were not simply doing science. In this land where so many people see the world in so many different ways, they were examining the very nature of the scientific enterprise, of this curious drive we have for gathering bits and weaving them into pictures of the world.
In fact, to some of the visitors making the drive up La Bajada to discuss their ideas with colleagues in Los Alamos and Santa Fe, it has become natural to think of information as the fuel that, quite literally, takes them over the divide. During one of the Santa Fe Institute conferences, Charles Bennett of IBM, who is one of the most influential proponents of this point of view, was said to have declared that given a long enough memory tape -- a blank string to be filled with 1s and 0s -- he could drive to Albuquerque. Several years later, at a conference in Dallas, called "The Symbiosis of Physics and Information," Bennett said he couldn't recall making the statement, but that it was not one with which he would disagree. "It's what I believe," he said. "It definitely sounds like something I would say."
To all but the handful of initiates it sounds impenetrably mysterious, this notion that information and energy could be somehow intertwined. To understand what Zurek, Bennett, Landauer, and their colleagues have in mind, one must become submerged in a way of thinking and carving up the world that has its origins in the late nineteenth century when James Maxwell tried to pick open a loophole in what was thought to be an unassailable universal law. In 1871, several years after inventing the equations braiding together electricity and magnetism, Maxwell publicly introduced, in his book Theory of Heat, an imaginary imp, later to be dubbed Maxwell's demon, that seemed to have the ability to out-think the Second Law of Thermodynamics.
In the age of the computer it is hard to imagine how something as prosaic as the steam engine could have done so much to shape nineteenth-century thought. Someday perhaps our own preoccupation with the digital computer will seem just as quaint. In contemplating how to get Robert Fulton's engine to mesh as closely as possible with the laws of nature, squeezing as much work as possible from the steam, Sadi Carnot, a French army engineer, concluded that even with his best possible efforts, he could never hope to reach an efficiency of 100 percent. In transforming the energy of the steam into the energy needed to turn a wheel, some would inevitably, irreversibly leak away. This truth was expressed in the form of the two laws of thermodynamics. The first law can be taken as the good news: it tells us that energy is indeed conserved, that it can neither be created nor destroyed, but simply changed from one form to another. The second law, however, tells us that whenever energy is put to use it is degraded: the potential energy of water stored behind a dam turns to kinetic energy and then to electricity as it rushes down the spillway and turns the turbine blades of a generator. In the end the accounts must balance: the energy coming out must equal the energy that went in. But not all of the energy of the water can be converted into electricity. Some is dissipated in the form of heat -- the friction of water molecules bumping into air molecules and into each other, the friction of the imperfect bearings on the turbine blades, the resistance of the electricity in the wires. The energy of the wasted heat is still somewhere in the environment, in the form of randomly vibrating molecules. We can imagine ways to recapture some of this random motion and channel it back into the system. But it can never be completely recovered. If it weren't for this loss, we could use a generator to power a motor and then use the motor to turn the generator and have a perpetual motion machine. As some scientists put it, the first law tells us that there is no such thing as an energy crisis; but the second law tells us that the entropy crisis is inescapable and never-ending.
Rudolph Clausius, in Berlin, was so struck by this inevitable change from useful to useless energy that he made it precise by inventing the concept entropy. Water above a dam, steam compressed in a chamber, a spring wound tight, a battery with its negative charges sequestered from its positive charges -- all are in highly structured states and are said to have low entropy. As they do work they become randomized. Viewed this way entropy is a measure of disorder, and what the second law is telling us is that the march toward randomness is inevitable. One can reduce entropy (water can be pumped back up hill; a dead battery can be recharged, its homogenized negative and positive ions sequestered between the two poles again) but only by expending energy. And this produces more entropy. Our refrigerators freeze shapeless water into the crystalline lattices called ice, but in doing so heat, the random vibration of molecules, is exported into the room. In the long run, entropy always wins. Pockets of order must be paid for with larger pockets of disorder and the system as a whole -- the universe -- inevitably winds down. We are fortunate in finding around us huge stores of potential energy, clocksprings already wound -- food, fossil fuels, rivers, uranium. By letting them flow down the energy hill we can run our civilization. For now, the whole system is continually recharged by the sun. But eventually it too must run down as, the second law tells us, the universe itself must.
There is also a third law of thermodynamics, which insists that it is impossible to reach absolute zero, the temperature at which all molecular motion would cease. Thus there will always be heat in the world, the energy of these randomly moving molecules. Another lesson of the second law is that it always takes more work to harness this scattered, ubiquitous motion than we can possibly gain from the attempt. Otherwise our cars and our appliances -- for that matter, trees, animals, anything that requires power -- could run by themselves, fueled by nothing more than this bottomless sea of vibrations.
It was quite a radical move when, in a thought experiment, Maxwell tried to devise a way to break the second law, to show that if a creature were clever enough it could create energy out of thin air. . . .
continued in Fire in the Mind: Science, Faith, and the Search for Order