Nervous systems, autopoietic systems, and hence, individuals are closed systems; however, these closed systems are sometimes treated as open systems even though they are not open.
In autopoietic systems the situation is different. For an autopoietic system as a homeostatic system that has its own organization as the essential variable that it maintains constant all the states that it can adopt without disintegration are equivalent in that they necessarily lead to the maintenance of its organization. The product of the operation of an autopoietic systemas autopoietic system is, under all circumstances, itself. Therefore, autopoietic systems are, by their constitution, closed systems without inputs or outputs. They can be perturbed by independent events, but the changes that they undergo as a result of these perturbations, as well as the relations of autopoiesis that these changes generate, occur, by their constitution, as internal states of the system regardless of the nature of the perturbation. An observer may treat an autopoietic system as if it were an allopoietic one by considering the perturbing agent as input and the changes that the organism undergoes while maintaining its autopoiesis as output. This treatment, however, disregards the organization that defines the organism as a unity by putting it in a context in which a part of it can be defined as an allopoietic subsystem by specifying in it input and output relations.
From these considerations, it follows that since we are living systems all our phenomenology as individuals is subordinated to our autopoiesis, otherwise we disintegrate; therefore, as individuals we are closed systems. (CS 460-61)
The result is the coupling of two constitutively different phenomenologies, the phenomoenology of the nervous system (and organism) as a closed homeostatic system, and the phenomenology of the ambient (including the organism and the nervous system) as an open non-homeostatic system that are thus woven together in a manner such that the domain of possible states of the nervous system continuously becomes commensurate with the domain of possible states of the ambient. (CS 463)
This page was last updated on July 8, 1996, by Rob Sable.