Instruction is the process in which input signals exert an influence on one or several output signal according to the rules of the system. Instruction does thus describe a directed triggering of a process and corresponds exactly to what has been said in the section above about the properties of a transitional system. A gene instructs the generation of an enzyme. By selection of suitable varieties can the yield of cultured plants be enhanced. The choice of suitable extern conditions may increase the production of plants.
Light controls the development of plants.
An instruction has always a certain intention. It is assumed that the system functions in a specific way. It is completely neglected which consequences this may have. Instruction describes therefore only parts of living systems and is never able to cover living systems completely because they are thought to be controlled, i.e. consequences arising from reactions are recognized, settled and used as a basis for future decisions. The resulting course of effects occurs in a closed circuit, the feedback loop .