System

Hall and Day (1977) suggest that “any phenomenon, either structural or functional, having at least two separable components and some interaction between these components may be considered a system.” Voinov () defines a system as “a combination of parts that interact and produce some new quality or function in their interaction”.

Systems are everywhere. We just need to learn to identify and see them. This helps understand the world around us, and to better know what to expect in the future. For example we can see how application of fertilizers by individual farmers can entirely change the ecosystem of the river or lake downstream, or realize how changes in individual behaviour can impact the course of a whole economy, or how people respond to changes in government policy.

We should keep in mind, however, that systems are constructs of our brain. There is no single objective description of reality in terms of a system. The description chosen will depend upon the goals, the purposes of the study, the available information about the objects that we study, the level of detail, the scale and resolution that we choose.

There are three important characteristics of systems:

• systems are made of parts, or elements;

• these parts are in interaction;

• the interactions between elements result in new features of the whole.

All the three characteristics are essential for a system to be a system.

Structure

The elements of a system and their interactions define the system structure. The more elements we distinguish in a system and the more interactions between them we present the more complex is the system structure. Depending on the goal of our study we can present the system in a very general way with just a few elements and relations between them, or we may need to describe many detailed elements and interactions. One and the same system can be presented in many different ways. Just as with the temporal and spatial resolution, the choice of the structural resolution or the amount of details about the system that you include in your description depends upon the goals that you want to accomplish in your study.

Function

Whereas the elements are important to define the structure of the system, the analysis of a system as a whole is essential to figure out the function of a system. The function is the emerging property that makes a system to become a system. Putting together all the components of a birthday cake, including the candles on top, generates the new function, which is the taste and the spirit of celebration that the cake delivers. Separate elements have other functions, but only in this combination they create this new function of the system.

Defining system function can be tricky. The same combination of elements can result in different functions. Describing the interactions between elements in a particular system design is essential to define the function. Consider a birthday cake, where the right combination of cream, crust, nuts and fruits is essential to deliver good taste. The same cake can be used in a food fight to smash in the face of your opponent. The function is to offend and abuse your enemy. The taste in this case really does not matter, but what becomes important is the consistency, density and combination of solid and liquid elements.

The function is therefore determined by the “use” of the system, from the viewpoint of the analysis. What is the function of system Earth in this case? From the anthropocentric viewpoint, we can say that its function is to provide habitat and livelihood for human beings. From a more ecological viewpoint, we could say that its function is to sustain life in general. From an astronomical viewpoint its function might be to provide the gravitational forces needed to keep the moon in orbit and to affect other planets and celestial bodies accordingly. We study systems for a purpose, and we describe systems in terms of those elements and interactions that are needed to best suit this purpose.

Delayed effects

Another feature often observed in complex systems are the so-called delayed effects. Systems and system elements do not always change immediately in reaction to external conditions or controls. With many elements and interactions involved, it may take considerable time for the signal to come through the system. Neither information nor material is transmitted instantaneously. As a result complex systems tend to behave counter intuitively, and they become hard to control. This is frequently observed in complex development related problems for which over simplified solutions are proposed. Another common phenomenon is that a change of policy might be claimed by its political advocates as having been very successful, when in fact the cause of success (desired change in a system’s performance) might in fact be more rightly attributed to a myriad of other elements in the system, or perhaps even to a change in the environment in which the system is located. It is easy to overshoot the target if you judge only on the past behaviour of the system.

Hierarchy

Every system is part of a larger system, or a supra-system, while every element of a system may be also viewed as a system, or a sub-system, by itself. By gradually decomposing an object into smaller parts and then further decomposing those parts into smaller ones, and so on, we give rise to a hierarchy. A hierarchy is then composed of levels. The entries that belong to one level are assumed to be of similar complexity and to perform a somewhat similar function. New emergent functions appear when we go from one level of a hierarchy to another.

For example, like other institutions, University of Twente has its own hierarchy, with the rector on top, followed by departments, staff, students, etc. Government typically also has a hierarchy from the bottom up: local, regional, national, and even some supra-national levels such as the European Union or the United Nations, though the status of supra-national bodies is not always recognized by national governments. Most private and civic organizations of any size will also have some form of hierarchy that is ideally established to facilitate the efficient and effective performance of its functions.

When analysing a system it is useful to identify where it can be placed in a hierarchy. The system is influenced by the higher levels and also by other systems at the same level. However, lower levels of those other systems are less important for this system. They enter the higher levels in terms of their function; the individual elements may be negligible but their emergent properties is what matters. Fiebleman (1954) describes this in his theory of integrative levels as follows: “For an organism at any given level, its mechanism lies at the level below and its purpose at the level above” .

According to Saaty (1982), “hierarchies are a fundamental tool of the human mind. They involve identifying the elements of a problem, grouping the elements into homogeneous sets, and arranging these sets in different levels.” There may be a variety of hierarchies, the simplest are linear, such as:

universe → galaxy → constellation → solar system → planet → … → molecule→ 
→ atom → nucleus → proton

The more complex ones are networks of interacting elements, with multiple levels affecting each of the elements.

Again, it is important to remember that there are no real hierarchies in the world we study. Hierarchies are always an abstraction created by our brain and are driven by our study. It is just a useful way to look at the system, to understand it, to put it in the context of scale, of other components that affect the system. There is nothing objective about the hierarchies that we develop.

A collection of rods, wires, nuts, bolts and various pieces of steel of particular form that are put together in a special way make an internal combustion engine, which can now run your car. We can look at the engine as a system made of all these elements. Separately many of them are quite useless. Being put together and interacting these elements produce a new quality, or a new function displayed by the whole.

The choice of elements and their interactions in our presentation of a system will depend upon our viewpoint, upon what exactly we are trying to understand and what are we trying to achieve in the study. For example, we may describe a farm as a system where we have a crop growing in a field with inputs of water, fertilizers, etc. The elements would be the plants, the nutrient content of the soil, available soil moisture. These elements will be connected by flows of material between the plants and the soil, which will define how the plants grow. On the other hand, the same farm may be presented as an economic system, where we will be concerned with costs of plants, fertilizers, irrigation, labour, fuel, etc. We will end up with quite different systems that describe the same real world object.