Georg Ivanovas From Autism to Humanism - systems theory in medicine
In order to apply systemic concepts, the system has to be defined, in the first place. The whole living being suggests itself by nature, as every subsystem (circulation, neurological organization or immune reaction) depends on the integrity of the whole. The behaviour of such a whole differs in certain regards from the behaviour of its subsystems. This is a logical consequence of centralisation and equifinality.
May be the best model to understand the singularity of a living ‘whole’ is the concept to of an autopoietic unit introduced by Maturana and Varela in their book The tree of knowledge, first published in 1987. A similar, but less precise model is discussed today under the header of robustness and evolvability (chap. 6.4).
According to Maturana and Varela the main principles of living systems are:
- structural determination,
- self-referential organisation,
- operational closure.
“All systems are structure determined, that is, they operate according to their own structure in any instant. This is the case for planetary systems, for weather, for tape recorders - any system; the operation of a system depends on its structure. This is also the case with living systems. The peculiarity of living systems is that their operational dynamics conserve living. Living systems are discrete entities that are constituted as such through their molecular dynamics; they are molecular systems that continually produce themselves “ (Maturana/Bunnell 2001a). The difference between the living and the automata is, according to Maturana and Varela the self-reproduction on a molecular level. “A living system is a network of molecules that interact with each other in such a way that through their interactions they produce the same kinds of molecules as the network that produced themand in doing so, constitute the whole network as a singular unity” (Maturana/Bunnell 2001a).
“Autopoiesis is not a way of saying “self organized”, nor does it imply that any system that is spontaneously organized or maintains its organization is autopoietic. All systems appear as spontaneously organized when the relationships that comprise the organization of that system begin to be conserved. Further, many systems are homeostatic or resilient. Living systems are unique in the sense that the network of molecular productions, which makes them a living system is the same network that produces itself something that is only possible in the domain of molecular dynamic” (Maturana/Bunnell 2001a).
This model defines the reconstruction of the own structure and organisation as the central characteristic for living beings and implies a ‘downward causation’ as the necessary means to do so. This far from being a trivial statement. It informs us about a certain hierarchy inherent in biological processes (chap. 6.12) and might suggest therapeutic strategies, as well (chap. 6.13).
This autopoietic unit exists in interaction with the environment. “Living systems exist as autonomous unities that realize their living through interacting with part of their environment in a manner that provides the necessary flow of energy and materials. This is true for a bacterium, a rose, a bear, or a human being” (Maturana/Bunnell 2001b).
“For example, the process of molecular productions that constitutes a living system cannot exist in isolation, it is only possible with a flow of matter and energy. Thus living systems can only exist by interacting with a medium that provides matter and energy. Living systems can only exist in a context, which provides them with a flow of matter and energy. Realizing this, we can be aware that organizations also only survive in a flow of matter and energy” (Maturana/Bunnell 2001a).
The molecular flow of energy and material can best be studied in the field of digestion which mainly takes place in the intestine. Food has to be broken down into molecular components in order to be absorbed. In the intestines the relation between me and other is somehow fluent (chap. 2.8.b).
The constant recursive exchange of the autopoietic unit includes other units. This is called structural coupling. The concept of co-evolution is such an example of a coupled development (Gilmore/Ferretti 2003). E.g., the propensity to carry non-pathogenic E. coli is a heritable trait (Ruby et al 2004). Also lactose-tolerance developed together with cattle farming (Beja-Pereira et al 2003). That is, inner structure and organization do not developed accidentally but according to the environmental conditions. Consequently, the genetic expressions seems to be altered more in the host when it comes to the host - parasite interaction (Nuismer/Otto 2005).
In an autopoietic system principles of life are conserved. It acts and reacts according to its inner structure. Confronted with a changing environment it has to balance these changes or the autopoietic unit cesses to exist. Such changes might induce a change of the inner structure representing a form of higher learning (chap. 4.3). Logically the environment does not constrain or determine the processes of the unit. The environment provides perturbations which trigger the inner behaviour of the unit.
The autopoietic model has been regarded as a major development in the study of living processes. But it is nothing different than Bernard’s concepts of an inner environment. “Vital phenomena are the result of contact between the organic units of the body with the inner physiological environment” (Bernard: 76). Even the symbol of Maturana and Varela to depict the autopoietic unit (illustration) is in line with Bernard’s thinking: “In complex organisms the organism of life actually forms a closed circle” (Bernard: 88).
This model has several not unimportant implications for the medical theory and practice. It has been demonstrated logically before that it is impossible to treat diseases (chap. 3.2). The autopoietic model gives a more detailed physiological explanation for this claim. Every therapeutical intervention is nothing else than a perturbation, a stimulus changing the inner regulation and structure (chap. 6.10). Although the concept of the physician might be different, on the level of biological ‘reality’ every kind of therapeutic intervention leads to a change of the inner regulation of the treated representing a certain type of learning.
The following section shall demonstrate certain consequences resulting from the organisational closure of the living using the examples of
- the neurophysiological subsystem,
- the biochemical subsystem,
- the visce-neuro-muscular subsystem.