Throughout this book we will discuss a number of historical examples of “international systems.” [Read more: Arnold Heeren and the idea of an international system] When we talk about a certain part of the world, it is above all the international system of that part of the world that will interests us. An international system, we said, is a system made up of political entities which are so closely connected to each other that they cannot ignore each other’s decisions. The international system constitutes an environment, as it were, which all of its members are forced to take into account. Take the example of East Asia. Here the Chinese empire was always the dominant power, but around China there were other political entities which pursued separate policies of their own. These smaller states — Korea, Japan, the Ryukyus, and so on — obviously had to pay attention to the Chinese, but the Chinese could not afford to ignore their neighbors either — as demonstrated by the fact that the Chinese empire throughout its history repeatedly was in conflict with assorted Central Asian tribes.
An international system consists of “political entities,” we said, and normally we would simply call them “states.” However, “state” is a term used in the context of European politics and for that reason it might be best to try to avoid it whenever we can. “Political entity” is a vaguer term which serves our purposes better. A political entity might be an independent city of merchants or a community of self-governing peasants, a religious order and even a business corporation. Which kinds of entities that qualify as legitimate members will vary from one international system to another. It is crucial, however, that the political entity in question should have the ability to act independently; to embark on its own actions, in pursuit of its own goals. This is what gives the system an international character. An international system, that is, is not the same thing as a state or even an empire. A state or an empire will contain many different entities to be sure but they are all subject to the same overarching power. In an international system, by contrast, the entities are independent of each other and they can act as they see fit. As a result there will always be a problem of how to organize relations between them. All international systems have a problem of order. This, in the jargon used by traditional scholars of international relations, is “the problem of anarchy.” Within a country anarchy refers to a breakdown of law and order, but in relations between states it refers to a system where power is decentralized and where there are no shared institutions with the authority to enforce common rules. Anarchy is problematic, and potentially disastrous, since it allows each state to think only about itself and to ignore the interests of the system as a whole. The result may be actions that threaten others, leading to increased insecurity and perhaps war.
But we should tread carefully here. Traditional scholars of international relations always have problems thinking outside of the box. That is, they have problems thinking outside of the box which their single-minded focus on Europe has put them into. It is the European international system that is identified as “anarchical” and this is why traditional scholars of international relations are inclined to think that anarchy is a problem of all international systems everywhere. Yet this is clearly not the case. Many international systems have been organized in a radically different fashion, and anarchy is only one options among many others. And this is the beauty of studying international systems from a comparative point of view. By thinking outside of the box, by thinking outside of Europe, we come to understand how limited our perspective has been. We suddenly have new ways of thinking about relations between states. To study of history is good for the imagination.
But let us think a bit more about the politics of international systems.[Read more: Kenneth Waltz and neorealism] What matters within an international system is more than anything which power a political entity has acquired, and relations within the system will differ dramatically depending on how power is distributed. By traditional international relations scholars this is often discussed as a question of “polarity.” This metaphor compares an international system to a magnetic field. Much as the north- and the south-pole attract or repel the needle of a compass, the poles in an international system attract or repel political entities. How many poles a system contains depends on the distribution of power within it. Thus we may talk about a “unipolar,” a “bipolar” or a “multipolar” international system. A unipolar system has one powerful state, a bipolar system has two powerful states, and a multipolar system has many powerful states.
The degree of polarity helps to organize the system and to give it a sense of directionality. Since the members are forced to pay attention to each other, they must face each other and thereby face away from non-members. Obviously, the more powerful a state is, the more we must pay attention to it. We often talk about important and powerful states as “central” to the system and less important and powerful states as “peripheral” to it. An anarchical international system where there are many powerful states can be compared to a pool-table where balls are bouncing off each other; a bipolar system with two equally powerful states is like a lever which is balancing on a pivot; and a hierarchical international system with one powerful state can perhaps be compared to a solar system where many small planets are circling around a sun. Clearly it makes a lot of difference whether we live on a pool-table, on a lever or in a solar system.