W. Edwards Deming, the guru of total quality management, defines a system as “a network of interdependent components that work together to try to accomplish a common aim.” 1 A pile of sand is technically not a system since the removal of a single component (i.e., a grain of sand) does not change the functioning of the collectivity (i.e., the pile). Furthermore, there is no “aim” designed into or emanating from the pile.
In contrast, a car is a system that comprises thousands of parts that all work together to provide transportation to a driver. If you remove the gasoline tank, then the car fails to perform its aim properly. In this case, the aim is designed into the car by the automobile design team, so the car is a mechanical, not a living, system.
Living systems are the most complex forms of systems. What makes them unique is that they interact with their environment and are self-organizing. As a result, the aim is not designed in but constantly evolving over time. Living systems can be something as simple as a cell, to something as complex as the European Union. Therefore, one of the ways of determining whether a collectivity is a system or not is (a) the interacting parts possess a central aim or purpose and (b) the removal of a component changes the functioning of the overall system. 2