"A system is a set of objects with relationships between the … in may be described generally as a complex of elements or components directly or indirectly related in a causal network, … Also, we are mainly interested in systems within which some process is continually going on, including an interchange with an environment across the boundary. It is generally agreed that when we deal with the more open system with a highly flexible structure, the distinction between the boundaries and the environment becomes a more and more arbitrary matter, dependent upon the purpose of the observer."

“For any given system, the environment is the set of all objects whose behaviour is influenced by the behaviour of the primary system, and those objects whose behaviour influences the behavior of the primary system.”

“The plan of the present paper is to discuss properties of systems more or less abstractly; that is to define system and to describe the properties that are common to many systems and which serve to characterize them all.”

“Synthesis of systems is much more difficult. Here science and engineering begin to take on aspects of art. A systems designer or planner not only must construct systems that work harmoniously individually and in tandem, he must also know a lot about the environment that the system is intended to match. Consideration of environmental factors requires foresight and experience; no one can ever foresee all the variables of importance and a choice of which to include is often a difficult one to make.”

“It is hard to say whether increasing complexity is the cause or the effect of man's effort to cope with his expanding environment. In either case a central feature of the trend has been the development of large and very complex systems which tie together modern society. These systems include abstract or non-physical systems, such as government and the economic system. They also include large physical systems like pipe line and power distribution systems, transportation and electrical communication systems. The growth of these systems has increased the need not only for over-all planning, but also for long-range development of the systems. This need has induced increased interest in the methods by which efficient planning and design can be accomplished in complex situations where no one scientific discipline can account for all the factors. Two similar disciplines which emerged about the time of World War II to cope with these problems are called systems engineering and operations research.”

“In our definition of system we noted that all systems have interrelationships between objects and between their attributes. If every part of the system is so related to every other part that any change in one aspect results in dynamic changes in all other parts of the total system, the system is said to behave as a whole or coherently. At the other extreme is a set of parts that are completely unrelated: that is, a change in each part depends only on that part alone. The variation in the set is the physical sum of the variations of the parts. Such behavior is called independent or physical summativity.”

“The basic functional elements of any automatic control system: sensing, converting, storing, communicating, computing, programming, regulating, actuating, and display . Many kinds of systems in being, speculated about, or even intuited, ranging from computers, most factory processes, communication systems, road networks, automatic farms, etc., have structures which can be invoked as zero-order matches to proposed sets of throughputs, especially for single- thread designs. This method of structuring is related closely to analogical design, of which a special form is called synectics.”