Oct 5, 2023 by Georgi Nikolov | 189 views
We often get confronted by a difficult problem - the lack of understanding of our environment, be that our community, organization or computer network. This originates from the structure of such systems, a finite amount of autonomous parts, which interact constantly with each other and produce unexpected results. Because of this inherent complexity, such systems are aptly named "Complex Systems". There is still some confusion in differentiating Complex Systems from Complicated Systems and in this blog we will try to give a quick overview of each.
Understanding what Complicated and Complex systems are is not a trivial task. Indeed, many make the mistake trying to treat a system, which exhibits all characteristics of a Complex System as though it is a Complicated one. Such an approach leads to many problems as the two can not be more different. A quick example to understand how we can differentiate them is comparing the how a computer functions to the internet.
By spending time researching different components, we can gain better understanding on which parts are needed and how they slot together to make a computer run. Each piece of hardware has a specific role- the hard disk stores data, the cables transport electricity, the motherboard functions as the backbone of the machine aiding the communication between the different components. If we apply the same methodology when looking at the internet, we quickly fall short to understand some of the elements of the system. Yes, computers, routers and humans are part of the system, but we also need to take into account the social aspect of communication between users, the vastly different types of data that is exchanged and how it interacts with each other, or even the geographical aspect which influences how internet is provided to remote places in the world.
Finally, we are confronted by the realization that Complicated Systems are systems we can understand by examining each of its parts and how they interact, contrary to Complex Systems where we need to take a step back and look at the system as a whole and try to understand it by examining the behavior and patterns it exhibits.
We are surrounded by different systems, each responsible for tasks to help us in our daily routine. We know how to use a fridge, drive a car or use a computer. But how many of us know exactly how any of those things are put together and how they function? Each of these systems is a collection of different parts, each with a specialized function, interconnected to serve a specific purpose.
This is what we call a Complicated system. As such, we can apply Reductionism philosophy and study the different underlying parts to understand the whole. This is a major aspect of Complicated systems- they are comprised of a finite number of simple elements, each of which interacts with the rest of the system in a clear and predictable way. For example, if we take the time and read up on it, we can understand using the schematics of an engine above, understand how the fuel circulates through the engine and affects the pistons to power it. There is a clear and direct cause and effect relationship between the different elements of the system, leading to a predictable interaction. If a problem arises, for example a part of the engine breaks, a skilled technician can use their knowledge of the system to single out the element causing this problem and correct it. This means that through in-depth specialized assessment of the System, a problem can be solved using specified rules which govern the System. Another aspect of a System governed by specific rules and procedures is that it is controllable and permanent solutions can be established for any problems which may arise.
What we can gather from this is that the defining features of a Complicated System are:
As mentioned earlier, to better understand Complex Systems we need to take a step back and view the system as a whole. To do this, we need to use the Holism approach and understand that the system can exhibit behaviors and patterns not inherited by the different components. Here we talk about "emergent behavior", patterns which are not regulated by the interactions between elements, but instead are created and adapt because of this interactions. The system in itself is considered dynamic and changes regularly to account for new patterns and new behaviors that might be adopted by the different elements. This means that we can not apply the same logic we use when dealing with Complicated Systems as there the elements interact in a strictly predictable way.
A "simple" example of a Complex System is road traffic, to make the parallel with the car engine we discussed when addressing Complicated System. We know the major components of traffic- cars, streets, traffic signalization (lights and signs), pedestrians and bikes. Each of this elements by itself is understandable, but when we bring them together, something almost organic is created and understanding or regulating it becomes a major issue. Further proof is the inability to completely solve congestion of freeways by adding extra lanes. It might seem counter-intuitive, we offer more space for cars but the adapted behavior and patterns lead to the same problems. This is governed by an aspect most people don't think about- the psychology of the elements. Indeed, when we assemble an engine, we don't need to take into account the changing mood or behavior of the elements, but when humans enter the picture the whole system changes. Further, we need to take into account things such as weather and its effect on the dynamic elements and the whole thing becomes exponentially more difficult to regulate.
To summarize, we can gather the following features of a Complex System:
To summarize the major differences between the two systems we need to review multiple topics, as discussed by Poli  and Blignaut :
There has been much research in the field of Complex systems, most currently the difficulty of managing Cyber-physical systems  and the complexity they exhibit. Often our greatest pitfall is the need of strict regulations and easy fixes, but those are not applicable when we are dealing with a system which exhibits almost organic growth and adaptability to its environment and outside stimuli. The only way to advance our understanding is to design new techniques for analysis of Complex Systems, be that through the use of Machine Learning or Visual Analytics. As final words I leave you with a quote from a cherished Sci-Fi author Douglas Adams:
There is a theory which states that if ever anyone discovers exactly what the Universe is for and why it is here, it will instantly disappear and be replaced by something even more bizarre and inexplicable.
There is another theory which states that this has already happened.
~ Douglas Adams, The Restaurant at the End of the Universe
 Poli, Roberto. "A note on the difference between complicated and complex social systems." Cadmus (2013).
 Van der Merwe, Susara E., et al. "Making sense of complexity: using SenseMaker as a research tool." Systems 7.2 (2019): 25.
 Baheti, Radhakisan, and Helen Gill. "Cyber-physical systems." The impact of control technology 12.1 (2011): 161-166.