If you have a liver disease, for example, a doctor usually can treat it without paying much attention to your heart or your tonsils (to stay on the same hierarchical level) or your personality (to move up a level or two) or the DNA in the nuclei of the liver cells (to move down several levels). There are just enough exceptions to that rule, however, to reinforce the necessity of stepping back to consider the whole hierarchy. Maybe your job exposes you to a chemical that is damaging your liver. Maybe the disease originates in a malfunction of the DNA.
A system, such as the body and the organ systems, isn’t just any old collection of things. A system is an interconnected set of elements (such as organs, tissues, cells, and cell organelles), that is coherently organized in a way that achieves something. A system must consist of three kinds of things: elements or subsystems, interconnections, and a function or purpose. For example, the elements of your digestive system include teeth, enzymes, stomach, and intestines. They are interrelated through the physical flow of food, and through an elegant set of regulating chemical signals. The function of this system is to break down food into its basic nutrients and to transfer those nutrients into the bloodstream (another system), while discarding unusable wastes.
Is there anything that is not a system? Yes—a conglomeration without any particular interconnections or function. Sand scattered on a road by happenstance is not, itself, a system. You can add sand or take away sand and you still have just sand on the road. Arbitrarily add or take away football players, or pieces of your digestive system, and you quickly no longer have the same system. When a living creature dies, it loses its “systemness.” The multiple interrelations that held it together no longer function, and it dissipates, although its material remains part of a larger food-web system. A system is more than the sum of its parts. It may exhibit adaptive, dynamic, goal-seeking, self-preserving, and sometimes evolutionary behavior.
You can see from these examples that there is an integrity or wholeness about a system and an active set of mechanisms to maintain that integrity. Systems can change, adapt, respond to events, seek goals, mend injuries, and attend to their own survival in lifelike ways, although they may contain or consist of nonliving things. Systems can be self-organizing, and often are self-repairing over at least some range of disruptions. They are resilient, and many of them are evolutionary. Out of one system, other completely new, never-before-imagined systems can arise.
Think about this. How does the Health Guardian know whether they’re looking at a system or just a bunch of stuff: A ) Can you identify parts? . . . and B) Do the parts affect each other? . . . and C) Do the parts together produce an effect that is different from the effect of each part on its own? . . . and perhaps D) Does the effect, the behavior over time, persist in a variety of circumstances?
A system’s function or purpose is not necessarily spoken, written, or expressed explicitly, except through the operation of the system. The best way to deduce the system’s purpose is to watch for a while to see how the system behaves. Keeping sub-purposes and overall system purposes in harmony is an essential function of successful systems, and in turn the function of the Health Guardian. A system generally goes on being itself, changing only slowly if at all, even with complete substitutions of its elements—as long as its interconnections and purposes remain intact.