Putting up walls

Putting up walls

Much of thermodynamics is about equilibrium, including the fact that two systems of different temperatures, when exposed to each other, eventually become the same temperature.

If thermal equilibrium is desirable, we can expend our efforts to maximize the exposure of the two systems to each other. Conversely, in order to keep them from reaching a state of equilibrium, some sort of insulating barrier is required. Similar to the experience of using a thermos to keep coffee hot, insulators can slow down the temperature change but cannot stop it completely.

« The physical world, all of it, only ever has one destination: equilibrium. » — Helen Czerski

What if we use thermal insulation as an analogy for contact between societies with different values? The comparison can highlight exchange and the effort of maintaining separation. Societies, however, have no single social temperature or equilibrium state determined by thermodynamics.

If we want to encourage equilibrium, then we can think of sharing as transfer of energy. There are three modes of heat transfer: radiation, convection and conduction. We can draw loose social analogies to these modes. For example, radio and TV radiate ideas across borders. Teacher-student exchanges act as intellectual and social convection currents. Brands and foreign aid conduct values. Mixing cultures gives them common ground. Sharing can create common ground, but it can also produce disagreement or new distinctions.

Sometimes, however, for various political or cultural reasons we decide we don’t want social or cultural equilibrium and so choose to erect an insulator in the hopes of keeping the two systems from mixing. Humans have been putting up border walls for millennia. They often serve a physical and psychological purpose, and are a line demarcating some sort of contrast. Us and them. My land, your land. Our values, your values. Our resources, your resources. The effects of these walls differed. Hadrian’s Wall, the Great Wall of China, and the Berlin Wall restricted movement to varying degrees without ending every exchange. Maintaining separation required resources, and no barrier controlled everything that crossed it. It is hard to keep groups of people from sharing ideas, customs, or language, just as it is difficult and expensive to keep a cube of ice solid on a hot summer day. Through social structures such as trade or marriage, borders tend to be places of exchange and social evolution. Two different states, whether of matter or people, will be impacted by what they are exposed to. An ice cube will undergo a temperature change if left outside in warmer air, and similarly a group of people will undergo changes in custom based on who they interact with outside their group.

« Division shapes politics at every level—the personal, local, national and international. Every story has two sides, and so does every wall. It’s essential to be aware of what has divided us and what continues to do so, in order to understand what’s going on the world today. » — Tim Marshall

The Romans, building Hadrian’s Wall from coast to coast in northern England, seemed to best appreciate the limits of what a wall could achieve. From the outset, “Hadrian’s Wall was not designed to withstand attack by a large and determined hostile army, for it was too long for the defenders to be strong at every point.” Rather, the wall functioned much like a border wall today. Its design was more about controlling the movement of people and goods versus stopping it completely. From the outset, it was accompanied by a diplomatic presence, with the Roman army regularly crossing its line to engage with local tribes, building relationships to gather intelligence and to try to deter major attacks.

The Romans knew Hadrian’s Wall would not stop a strong enemy force, and thus the placement and design was about slowing down aggression or giving the Romans the opportunity to be proactive by developing relationships with those on the other side. Trade continued, information and materials were shared, and personal relationships were maintained by those living on both sides. Hadrian’s Wall thus was just one part of the overall strategy to maintain contrast between Roman territory and the tribes of the north. Controlling the interaction between both sides of the wall, instead of trying to stop it completely, was enough for the Romans, probably because they realized that there is a significant cost to improved insulation. Border walls do not do their jobs on their own; they need to be augmented by border personnel. As Adrian Goldsworthy writes of Hadrian’s Wall, “Ultimately, its success rested less on the fortifications and barriers than on the soldiers who manned them.” A wall’s effects depend on how it is staffed and governed, as well as its physical design.

With Hadrian’s Wall, the Romans did not try to end every interaction across the boundary. They recognized that the resources required to prevent any interaction across the border were more than they were willing to invest. They seemed to accept that their society could function as desired despite the influence from the cultures on the other side. To relate to thermodynamics, if we think of Roman culture as “hot,” Hadrian’s Wall acted as an insulator; it slowed down the cooling from exposure to other cultures but did not stop it completely.

« But a boundary line, as any military expert will tell you, is also a potential battle line, for a boundary line marks off the territory of two opposed and potentially warring camps. » — Ken Wilber

Another famous wall that teaches us a lot about social equilibrium is the Great Wall of China. Walls have been going up between present day China and Mongolia for at least 2,000 years. Far from the restored stone wall that captures imagination today, there are actually many walls built of different materials, executed by many different dynasties along this northern border.

The history of these Chinese walls illustrates the expense and difficulty of controlling a long boundary. Thermal insulation is a useful comparison for that effort, but assessing a particular wall requires asking what it was intended to do and what it achieved.

First, walls are expensive. There is the maintenance, as well as provisioning for the people stationed at them. Second, people can go around or over walls, because walls have to end somewhere. The Chinese walls were an expression of political desire to set the location of the northern border, and as Julia Lovell explains in The Great Wall, they were not purely defensive structures. Instead they often pushed into foreign territory as a way of asserting claim. So, these walls were often not close to major centers and they covered vast territory. Not only did they have to be staffed, they required that outposts and associated supply lines be maintained in order to provision them.

Right from the beginning there are stories about the essentially slave labor that was used to build the Chinese border walls and the horrible living conditions for those who staffed them. What good are walls without the loyalty of the troops stationed at them? Not much. The Great Wall was quite porous because “invaders could make detours around strong defenses until they found weaknesses and gaps,” and it was often staffed by guards who made a better living accepting bribes from those wanting to cross.

Lovell describes the Ming dynasty attitude toward the Great Wall as “define, enclose and exclude” which sums up the entire philosophy behind the Chinese border walls right from the beginning. On the one hand was the desire to keep the barbarians out. The nomads from the steppes of present-day Mongolia, the most famous of which was Genghis Khan, were a constant threat to the Chinese people. But there was also a desire to keep Chinese culture in; to not pollute it with the ideas and sensibilities of others. The walls were thus also inward-looking, a way of maintaining “cultural superiority.”

However, as Lovell describes, “it was not the case that border walls absolutely and immovably separated a culture of rice, silk and poetry on the one side from a culture of horse milk, pelts and war on the other.” There was a lot of intermingling. There were ethnic Chinese. They were invaded by barbarians. The barbarians adopted some Chinese ways. They became the new ethnic Chinese, who were, in turn, invaded by barbarians. This cycle played out multiple times over the centuries, influencing the development of Chinese culture. Shared customs can change how groups perceive one another, without eliminating every distinction between them.

Lovell tells a story of a ruler deliberately adopting practices from a neighboring culture:

In 307 BC—in the middle of the Warring States period—King Wuling of the northern state of Zhao started a court debate about fashion: should upper garments be buttoned to the left or down the middle? Behind this seemingly frivolous and innocuous question of style lay a strategic issue of huge political and cultural significance. King Wuling planned to swap the traditional Chinese gown for the side-buttoning tunic of the nomads, and the aristocratic Chinese chariot for their mounted archers. Embedded in the mooted change of dress was a revolution in worldview: an acceptance of the military superiority of the nomads and of the need to fight them on their own terms.

Thus the history of China is not the story of a culture that managed to completely insulate itself and remain “pure.” Current Chinese culture is composed of influences and ideas that were exchanged along its borders.

Of all the walls in history, the Berlin Wall stands out as one that was erected to be an absolute, uncompromising barrier that was intended to prevent the mixing of two ideologies; to restrict exchange. Walls don’t just restrict physical movement: they can shape and modify ideas and social norms.

The Berlin Wall was different from Hadrian’s Wall and the Great Wall of China in that it was less part of a military and diplomatic strategy and more a psychological barrier. It was not designed to facilitate interaction with potentially hostile tribes (like Hadrian’s) or to claim territory and preserve culture (like China’s).

The Berlin Wall tried to stop the movement of ideas as well as people. Soviet Communism and its East German counterpart depended on behavior-shaping propaganda and psychological controls, neither of which would work if challenged by outside economic or political ideas.

The Berlin Wall was built above all to stop people leaving East Germany through West Berlin. After World War II, Germany and Berlin were divided among occupying powers. West Berlin provided an escape route within the Soviet-controlled East, making it a particular concern for the East German authorities.

Berlin was occupied by Britain, the United States, France, and Russia after the war. Until 1961 it still functioned as one city, which allowed for an escape route for those who wanted to leave communist East Germany. As Frederick Taylor explains in The Berlin Wall:

Between 1945 and 1961, some two and a half million fled in this way, reducing [East Germany’s] population by around 15 per cent. Ominously for the Communist regime, most emigrants were young and well qualified. The country was losing the cream of its educated professionals and skilled workers at a rate that risked making the Communist state totally unviable.

During the summer of 1961, the exodus reached crucial levels. Every day, thousands of East Germans slipped into West Berlin and from there were flown to West Germany itself along the so-called “air corridors.” The regime was not prepared to abandon the political and economic restrictions that fueled the hemorrhaging of its brightest and best.

So they built a wall. And not just any wall—one with multiple layers of complexity and deterrents. In addition to the structure above ground, subway tunnels, sewers, and anything that could give passage to the west was sealed off or modified so that human passage was thwarted.

The Berlin Wall never worked completely. People still crossed, albeit at huge risk, and some lost their lives in the attempt. But what is even more remarkable is that the Berlin Wall contributed to the very ideology it was trying to keep out. Restricting the population’s freedom also helped undermine the legitimacy the East German state sought to maintain. The pressure built until one day, in November 1989, it was taken down by the very people it had been trying to keep apart.

The Berlin Wall shows both the power and the limits of a barrier: it sharply restricted movement for decades, yet did not stop outside information or survive the political changes that opened the border. Its fall was a historical event involving people and institutions, rather than an inevitable consequence of heat exchange.

An insulator slows heat transfer. By analogy, a social barrier may reduce contact while leaving some exchange possible. The practical questions are what kind of exchange it restricts, what maintaining it costs, and whether it serves its intended purpose. The analogy cannot tell us how long a particular wall will last.