STATE of a SYSTEM
| Collection | International Encyclopedia of Systems and Cybernetics |
|---|---|
| Year | 2004 |
| Vol. (num.) | 2(2) |
| ID | ◀ 3179 ▶ |
| Object type | General information |
- “A recognizable condition of a system (G. PASK, 1961, p.117).
- “The set of numerical values which the variables of a system have at a given instant” (W.R. ASHBY, 1960.2, p.16).
- “The set of relevant properties of a system at a moment of time” (R.L. ACKOFF, 1972, p.84).
- “A particular pattern of relationships existing among the components and the particular filtering condition of the boundary” (K. BERRIEN, 1968,p.32)
Such generally synchronic descriptions — very complex in some cases — take their full sense only when repeated many times at succesive instants, i.e. when becoming diachronic. Some features of the systems successive states may be conserved or may reappear periodically or irregularly, which comes to reflect precisely the systems identity: Multiple stationary states are possible.
While, according to H. PRAEHOFER the present state “… represents a memory of the past of the system” (1991. p.292), such memory is frequently in part or totally illegible. The claim to be able to compute the future of a system “… just knowing the current state and the future inputs” (Ibid) seems to be in most cases a Laplacian fallacy.
The study of specific transitions from one state to a sequence of the other states through time is a common method to learn about the systems behavior. However, even the observation of only one instantaneous state may bring some knowledge of the system to the observer, as he usually relies on connectable knowledge obtained from previous experiencies. In ASHBY's words: “If he sees two cogs enmeshed he knows that their two rotations will not be independent, even though he does not see them actually rotate” (1950, p.19).
Nevertheless ASHBY hastens to add: “… the unexpected sometimes happens; and the only way to be certain of the relation between parts in a new machine is to test that relation directly” (Ibid).
From a quite different viewpoint, E. LASZLO states: “The fact is that systems in the real world can exist in one of three types of states. Of these three, one is radically different from classical conceptions: it is the state far from thermal and chemical equilibrium. The other two states are those in which systems are either in equilibrium or near it” (1987, p.20).
The first of these two is the maximum entropy one,… when the system ceases to be a system. The other one is the common state of dynamic stability through fluctuations constrained within limits.