OBSERVABILITY (Constraints on)
| Collection | International Encyclopedia of Systems and Cybernetics |
|---|---|
| Year | 2004 |
| Vol. (num.) | 2(2) |
| ID | ◀ 2332 ▶ |
| Object type | Epistemology, ontology or semantics |
M. NOWAKOWSKA states (1986, p.52-4) as follows the observability problem: “The phenomenon to be observed is assumed to be described in terms of n attributes, say y$_{1}$…y$_{n}$. To determine the state of the phenomenon at any given time, one needs to know the values of all components.
- “The constraints on observability may be of three types. Firstly, it is quite common that values of a given variable can be known only up to some precision” (p.52).
Practically this is always the case. For this reason, as noted by this author, it is generally necessary to use statistics. But in this case, it is implicitly admitted that a mean between observations of many similar states of many similar phenomena can validly be used.
- “Another kind of restriction on observability is of conditional character: it is typified by a constraint that, if y$_{i}$ assumes a value in some range, then one cannot observe the value of variable y$_{j}$… In practice such situation occurs when some values (usually the extreme ones) cannot be observed at all, or prevent observations of some other variable or variables” (p.53).
- “Finally, the third type of constraint concerns joint observability; it is typified by the situation where y$_{i}$ and y$_{j}$ may each be observed, but not jointly” (p.53).
This is basically the indeterminacy (or uncertainty) problem, very basic at quanta level.
- “Of course, all three kinds of constraints may operate at the same time in a given phenomenon” (Ibid).
The use of the concept of “state of the phenomenon” clearly shows the fundamental ambiguity of any observation, that is always trying to “solidify” a dynamic succesion of events into a sequence of static states (sorry for the pleonasm!).
In synthesis, even leaving aside physiological limitations, we are always trapped within our mental dichotomy between time and space.