International Encyclopedia of Systems and Cybernetics

1. "The context in which a system exists" (1973, p.86).

B. BANATHY states: "It is composed of all the things that surround the system, and it includes everything that may affect the system and that may be affected by the system" (Ibid).

Of course, the whole universe is the environment of any system. Practically we must thus define in a more restricted way the environment of the system as those parts of the general environment that interact with it more or less strongly and/or permanently. However, there is a snag (or two):

a – Two different observers may very well have different descriptions of the system's environment (pursuing either the same- or a different goal)

b – There is never any absolute certainty that the observer did not forget, or be unable to register some important part of the environment.

An incorrect or incomplete evaluation of the environment is the main cause of most of the technological and social catastrophes engineered nowadays by ill-advised planners.

2."Those variables whose changes affect the organism (system) and those variables which are changed by the organism's (systems) behavior (W.R. ASHBY, 1960, p.36).

A more or less equivalent definition by S. KATZ is: "… everything the nervous system may use as a source of knowledge" (1976, p.45).

ASHBY states: "It is thus defined in a purely functional, not a material sense"(Ibid). There are reciprocal feedbacks between the environment and the system. ASHBY cites STARLING, who wrote: "Organism and environment form a whole and must be viewed as such" (1960, p. 38). Unfortunately, this necessity is very frequently ignored, even by high level systems designers of the most various kinds: physicians, engineers, economists, agronomists, etc.

In the words of M. DODDS and G. JAROS "… the environment is not a neutral laboratory, but a stakeholder with its own needs" (pers. comm.).

This very serious problem is related to J. FOURASTIÉ's "Ignorance of ignorance" or to G.de ZEEUW's "invisibility": a part of the significant environment is not perceived.

3. "For a given system, the environment is the set of all objects a change in whose attributes affect the system and also those objects whose attributes are changed by the behavior of the system" (A.D. HALL & F.E. FAGEN, 1956, p.20).

While this very old (1956) definition looks quite rigid, HALL and FAGEN have it perfectly clear that "The statement above invites the natural question of when an object belongs to a system and when it belongs to the environment; for if an object reacts with a system in the way described above should it not be considered a part of the system? The answer is by no means definite. In a sense, a system together with its environment makes up the universe of all things of interest in a given context. Subdivision of this universe into two sets, system and environment, can be done in many ways which are in fact quite arbitrary" (Ibid).

These comments are allowable, but their importance should not be over-emphasized: In most practical cases, it is easy to distinguish the system within its environment, mostly so when it is a strongly integrated system. This being the case, the only doubt is about some border elements.

Even composite systems (snowfields, locusts swarms, human masses) can be more or less easily distinguished from their environment.

Environment (Types of)

R.O. MASON distinguishes four different types of environments (for organizations, but it seems applicable to any type of systems):

"1. Placid, randomized: In the simplest type, goals and noxiants are relatively unchanging in themselves and randomly distributed. A critical property from the organization's viewpoint is that there is no difference between tactics and strategy, and organizations can exist adaptively as single, and indeed quite small, units. The implication of this environment for a system is that it makes it stable and relatively unchanging…

"2. Placid, clustered: (this) type is also static, but goals and noxiants are not randomly distributed; they hang together in certain ways. Now the need arises for strategy as distinct from tactics. Under these conditions organizations grow in size, becoming hierarchical and tending towards centralized control and coordination…

"3. Disturbed, reactive environment: (this) third type is dynamic rather than static. It consist of a clustered environment in which there is more than one system of the same kind, i.e. the objects (sic) of one organization are the same as, or relevant to, others like it. Such competitors seek to improve their own chances by hindering each other, each knowing the others are playing the same game… Control becomes more decentralized to allow (operations) to be conducted. On the other hand, stability may require a certain coming to terms between competitors.

"4. Turbulent fields: The fourth type is dynamic in a second respect, the dynamic properties arising not simply from the interaction of identificable component systems but from the field itself… The turbulence results from the complexity and multiple character of the causal interconnections… At this fourth level the concept of efficiency is superseded by the concepts of survival and effectiveness" (1979, p.18-19).