2 Section readings – Flows and feedback
Reading 4.1: Systems thinking: the first step
The processes of analysis and synthesis in conventional thinking are based on the concept of an object. An object is something that can be clearly distinguished from its environment and can be characterised by its attributes. Attributes enable categorisation schemes that are the basis of our normal thinking. So when you look at a particular ecosystem, for example a pond, you find different animals and plants. And if you look at any ‘book of the pond’ you find each animal and plant described in terms of the attributes you can recognise it by: at the first level is it an animal or a plant, if an animal then at the second level is it a fish, or an amphibian, and so on. But this scheme tells you nothing about how the pond functions as a dynamic system.
The first stage of the development of systems thinking recognised that reductionist thinking was flawed and did not enable interconnections and interrelationships to be taken into account. This gave rise to the first idea of a system being a set of interrelated objects. The disciplines of system dynamics, complexity theory and chaos theory all arose from this first step. In the next few resources, I will explore the basic ideas of this approach and how you can use the ideas in a powerful way to explore the problems raised in the previous section. In Part 6, I will introduce the second stage of development of systems thinking.
In examining our pond, the most obvious interrelationship between the plants and animals, is that some plants and animals are food for other animals and without the food of course they would die of starvation.
I have started identifying ‘objects’ (a pond and some of its components – plants and animals) and highlighted one relationship (some organisms provide food for other organisms). If you visualise the pond system as flows of energy and matter (food) between objects (plants and animals) then you can start building a picture of the pond system’s structure (the objects and their relationships) and function (the purpose of the various interactions). I have already identified one function of the pond system – food web support. In other words, a pond sustains the flow of matter and energy through a web of living organisms as one feeds off the other. Each object within the food web could be characterised by a range of attributes describing quantity (e.g. level of biomass) or quality (e.g. relative health). At the same time, you can start linking the objects together so that you can represent the food web support function.
In building a picture of food web support within the pond system, you need to exercise both your skills in analysis and synthesis (see Figure 4.1). Analysis is needed to identify the various objects. For example, you may want to break down one object (animals) into several objects (herbivores, carnivores, parasites). You could continue doing this ad infinitum: species; age cohorts; individuals; organs; etc. Synthesis is therefore needed so as to not lose sight of the primary aim of your investigation – identifying the objects and relationships that contribute towards the pond system’s food web support. One could consider synthesis as a check on the amount of unnecessary and irrelevant analysis.
Ponds, like all living systems, are not static. A major component of systems thinking is therefore coming to terms with the dynamic nature of systems. The next set of readings will take a closer look at two fundamental types of relationships objects can have: positive and negative feedback. These can be considered the conceptual foundations of systems thinking.