The behavior of a system is the change in its state or its state variables that can be observed at the macro level . An event is the transition from one state to another. Laws can be recognized here even without knowledge of the micro level. However, these regularities can only be explained by the system structure .
These changes can
- take place independently, without external influences (" intrinsically ")  → or
- related to an influence from outside (" extrinsic ") →  →.
- It can also be observed that a system shows no change despite an external influence → .
Synonyms for influence and effect:
|→ [||] →||Terms from|
The number of possibilities which influences can act on a system, as well as the number of possible reactions, depends on the structure of the system. From the simplest system with only one input option and one output option ( example: hamstring reflex ) to a large number of options with adaptive and learning systems, all transitions are conceivable.
Influence and effect can be substance or matter , energy and information flows . All combinations are possible. ( Example: when a car brakes at a traffic light, information causes the release of energy ).
The relationships between influence and effect can be viewed from two perspectives:
- qualitative : the type of influence determines the type of effect. (Principle of the stimulus-response link in ethology).
- quantitative :
- a) the strength of an influence determines the strength of the effect
- b) the influence determines the direction of the effect (in the same direction, directly proportional: E ~ A or in the opposite direction, indirectly proportional E ~ 1 / A);
The behavior of systems can have an effect on their own state:
- direct ( example: instinctual action chains )
- indirect: The behavior of systems can influence the behavior of other systems and these act back on them. ( Examples: material cycles such as the global carbon cycle , recycling )
Influence without observed effect → 
- Trivial case: The system cannot pass on or process the influence due to a lack of structures.
- The external influence is so weak that the stimulus threshold given by the system cannot be exceeded.
- The system is so sluggish that it practically does not react during the observation period. (see hysteresis )
- The system has compensation mechanisms in order to maintain its steady state ( equilibrium state ).
Example : The disruption of a chemical equilibrium by changing the concentration of the starting materials or products does not change the state variable of the equilibrium constant. However, the equilibrium concentrations are changed. Here it becomes clear how the determination of behavior depends on which parameters are considered relevant and therefore observed.
Change of state without observed external influence  →
- Radioactive decay;
- Behaviors based on an internal clock, e.g. B. wake-sleep rhythm, autonomous heartbeat
Correlations can be established between influences and effects →  →