The System as a Fundamental Construct
The previous chapter ended by indicating that when the human interacts with an equipment, the combination forms an entity--the system--that has properties that are different than those of either one alone. The idea of the system is a construct, which means that it is a concept whose characteristics are manifested concretely in physical and behavioral phenomena. The distinction between the idea and the phenomena that represent the idea must always be kept in mind because it is easy to become confused if the two are not differentiated. The system is critical to HFE theorizing because it describes the substance of the human-technology relationship. Anyone observing the stew of humans in real-life interactions with technology and wishing to organize it conceptually, classifying it into describable units, must inevitably see this activity in terms of systems.
The essence of the system concept in its most general form is that an entity is composed of subentities that, when arranged in a rational organization, are different from the superordinate entity. The superordinate entity is the system; the subentities of which it is composed are subsystems and individual human-machine combinations.
The reader may ask: Why is the system concept so critical to the understanding of the human-technological relationship? The reason is that, without some such organizing concept, one cannot combine the individual human-machine combinations into something more complex than their individual units. Without the system as a means of combining individual phenomena into larger units, the phenomena remain individual, although one can observe that in reality individual units and their phenomena do combine into larger entities. For example, American Airlines is much more