A system has three components: elements, interconnections, and function.
Elements are the visible components of the overall system. Interconnections are the relationships through which those elements interact. Function is the ultimate goal achieved through those interactions, and it is also what determines what kind of system it is. So if a collection of things can connect and interact with one another to perform a function, it can be called a system of that kind.
A collection of electronic components that uses electrical current and data transmission to simulate the functions of a brain is a computer system.
To master it, you need a thorough understanding of how systems operate, which brings us to three concepts of system operation.
Stocks, flows, and feedback loops.
A stock is an accumulation of data or information within the elements of a system—for example, the water level in a reservoir in a drainage system or the number of patients in a healthcare system.
A flow is the movement of data or information through system elements—for example, the amount of water flowing into and out of a reservoir, or the number of people admitted to and discharged from a hospital. A loop, or feedback loop, is how flows affect stocks. There are two main types: reinforcing loops and balancing loops. A reinforcing loop accelerates change in a stock and follows the pattern: the more A, the more B; the more B, the more A. For example, the stronger a certain medicine becomes, the less of it there is, and the less there is, the stronger it becomes.
A balancing loop keeps a stock stable. Its pattern is: if there is too much, it decreases; if there is too little, it increases. For example, if you are too discouraged, you are encouraged; if you are too arrogant, you are brought down a peg. A reinforcing loop is like a snowball rolling downhill; a balancing loop is like a roly-poly toy.
A system has elements, connections, and functions. Stocks exist within elements, flows occur between elements, and flows form loops that, in turn, control the state of stocks. To understand systems thinking, you need to understand all six of these: What are the elements? How are they connected? What functions do they serve? How much is in stock? How do flows change? What loops are there?
A grassland system has three elements: grass, sheep, and wolves. Their connections arise through eating and being eaten, and their function is to maintain ecological balance. A patch of grass, a flock of sheep, and a den of wolves are stocks. The amount of grass eaten and the number of sheep eaten by wolves are flows. More grass means more sheep, and more sheep means more wolves. But more wolves mean fewer sheep, and fewer sheep allow the grass to grow again. These three elements form a balancing loop. Viewed in isolation, wolves eat sheep, so without wolves there would be sheep. Viewed as a system, wolves eat sheep, while sheep eat grass; if the grass is eaten up, there will be no sheep. So it is because there are wolves that there are sheep.
The barrier to mastering systems thinking is high, and solving problems with systems thinking is often not well received either. There are three reasons:
It is not intuitive. To ordinary people, it may look like you are going about things in a roundabout way, taking an indirect approach, or rushing to put out a fire at its source. There is a way to save a forest from a wildfire: light another fire in the area below it. You know that, right?
It does not produce quick results. When it comes to exercising and strengthening the immune system, it will never be as popular as taking whatever medicine treats whatever illness you have. Downwind, in the area where the fire has already burned, the fire from upwind will not spread there. You know that, right? But you have to wait for the fire to burn through slowly. You know that, right?
It is difficult to explain. Understanding a system is already hard, and you also need to be articulate enough to explain it clearly to others. You also have to hope the other person is mentally engaged; if any one link fails, it will not work. When the fire from upwind has burned over and the fire downwind has also just passed through, we retreat to the burned area. Stop yapping—the fire is already right in front of us, and there is not even enough water. Are you still complaining that things are not chaotic enough? You are even lighting another fire. Have you lost your mind?
Therefore, systems thinking is destined to be something everyone knows about and everyone advocates, but in practice, it is not easy to put into action.