To arrive at a “theory” of systems requires several levels of abstraction form comparing a wide range of natural and human systems. While workers have been doing this for ages, one rarely encounters a deep examination of how accurate abstraction should be performed. But this is the very most fundamental act of assembling a theory of systems. It must be very carefully studied.
It is much more direct to call these “rules.” However, there is a danger in naming them rules. Most of us think of rules as things that must be followed. We are too early in the testing of theories of systems in general to call these rules. Nevertheless, this is the intent of the exercise. To detect poor abstraction from good abstraction. See later on in Systems Application the equally important Rules for Deabstraction.