System Theory: A Survey

Abstract

This chapter will give a brief survey of the developments and history of general system theory. The nature of this field is somewhat ambiguous as it applies to a number of trends in system science. During the past few decades, there has been an effort to counteract the increasing amount of specialization by creating a unifying concept that can be applied to many disciplines. The central idea, which lies at the core of general system theory, is, of course, the concept of a system. Although many definitions have been advanced, there are essentially two different types. The real, real world, or concrete system, is a bounded and cohesive part of the empirical world. It may refer to widely different objects, such as a star, a company, or a state. The object is delineated by a boundary, which separates this entity from its environment. An exchange of material, energy, and information can take place across the system boundary. The influence of the environment on the system is called the input, while the influence of the system on the environment is called the output. A further distinction can be made between open systems, which are in interaction with their environment, and closed systems, in which this is not the case. The organismic system theory is essentially based on this concrete system (see section 1.4). Another system definition is given by the concept of an abstract system. It is a mathematical construct with input, output, and other variables, as will be discussed in section 1.2. The system is now defined by these variables and a number of mathematical relations.