System Function

Separating the physical world from the mental space helps us understand the difference between a system and its function. For example, a car is a physical object that exists in the real world. It is the implementation of the system, or a physical object you can touch. A car, like any system, has a function—in this case, movement. Movement, like any system function, is abstract; you cannot touch it. However, we can observe movement—or more precisely, we see the car as it moves.

A function (or behavior, or action) is assigned by people; things do not choose their own functions. A hammer cannot assign itself the function of driving nails. An interested party can take a microscope and designate (call) it a "hammer," that is, assign it the function of driving nails. In this case, the hammer is nothing more than a role for the microscope—or for a stone. Then, the behavior (function) of the microscope in this role is driving nails.

People are interested not so much in the thing itself (the material object) as in its function. That is what interested parties value, although a layperson rarely distinguishes between these perspectives. A system skill involves separately considering and discussing the function that someone needs, and the structure (physical object) that is best suited to perform that function.

The mental technique of separating a system from its function can also be applied to thinking itself. We can say that thinking is a function of the intellect. In this case, the intellect is the system, and thinking is its behavior or function.