INVARIANCE (Time)
| Collection | International Encyclopedia of Systems and Cybernetics |
|---|---|
| Year | 2004 |
| Vol. (num.) | 2(1) |
| ID | ◀ 1775 ▶ |
| Object type | Methodology or model |
The invariance of the set of states of a system that do not change in time.
What may change is the presence of the system in one or another state. Even so, this is a quite theoretical state of affairs, based mainly on the hypothesis that the different states do not influence each other.
According to H. MARGENAU (quoted by A.D. HALL & R.E. FAGEN) the absence of time in the equations describing a system is the very essence of causality (in its strictly deterministic sense). It is the case for “a system completely specified by n variables x$_{1},$x$_{2,}.$x$_{n}.$. Then… the state of the system is uniquelely describable by a set of n numbers. To borrow terminology from physics, the set of all points in n-dimensions is called phase space” (l956, p.25).
This type of description becomes thus an algorithm with a well characterized content, even if it may correspond to a matrix of probabilities. (See “Markovian matrixes”).
However, “When the constants of the set become functions of time, as in progressive segregation or systemization, the definition is no longer satisfied” (Ibid).