202401291425 Definition of system

So what is a system? A system is a set of things — people, cells, molecules, or whatever — interconnected in such a way that they produce their own pattern of behavior over time. The system may be buffeted, constricted, triggered, or driven by outside forces. But the system’s response to these forces is characteristic of itself, and that response is seldom simple in the real world.¹

Systems are combinations: sets of things that combine to create behavior. Systems exhibit 202104291540 Emergence.

We our complex systems — our own bodies are magnificent examples of integrated, interconnected, self-maintaining complexity.¹

Systems must consist of elements, interconnections, and a function or purpose. Elements are easy to see, interconnections harder, and purpose hardest.