International Encyclopedia of Systems and Cybernetics

The progressive buildup of the structural organization of a system and of the interrelations among its parts.

Already in 1952, A. TURING demonstrated, at least theoretically that some chemicals homogeneously distributed at the start, may, by reaction and diffusion, lead to different concentrations, which can then form spatial structures. Allegedly, and against what CASTI states, these "TURING structures" have been obtained in France in 1990. (S. DOUADY and Y. COUDER, 1993, p.32).

Morphogenesis, once started, is unavoidedly a systemic process. It is also a social one because it organizes the differentiation of parts, elements, individuals or subsystems that will have to interact during the whole existence of the system.

Morphogenesis thus defined takes place in a system already endowed with organizational closure. It consists in the progressive development of a set of catalytic hypercycles – i.e. periodic phenomena – which expresses its potential to reach a final level of dynamic stability.

During morphogenesis, any growth process remains closely channeled within maxima and minima limits (WADDINGTON's chreods). Structural organization may be modified, even deeply, through geometrical and topological transformations, but never in such a way as to alter the initial and basic identity of the system.

According to H.T. ODUM, morphogenesis is a result of progressive selection of successive loops which become stabilized if and when some outputs are repeatedly fed back into those functional circuits that are able to produce them anew. (see "reward loop"). As the initial cause of such circuits he sees "the initial proliferation of many possible connections more or less at random (which) constitues the choice generation" (1977, p.154).

The most significant part of this statement may well be "more or less": Absolute randomness is obviously impossible, as any system has some specific antecedents. (See the critique of von FOERSTER's "order from noise" experiment).

However ODUM's view introduces us into the social aspects of self-organizing systems.

For A. WILDEN, morphogenesis is the characteristic of a complex and evolving system which adapt itself by transforming its structures.

According to WILDEN the term should be reserved for the behavior of "complex systems, such as societies… No individual organism is able to adapt and develop itself outside of narrow limits – in view that any growth process is a positive feedback which must be inhibited – while the morphogenetic system can adapt itself by transforming its structures" (1972, p.58).

Again here, "narrow" remains a matter of definition.

It could possibly be said that any system undergoes a period of social organization (biological, neural or groupal of some kind), corresponding with its growth, before it reaches its mature state. Some basic original template creates and transforms the structures of the system in a repetitive process of at least partial destructuration and restructuration, i.e. reorganization of interrelations among elements. It would seem that this is confirmed by the research in developmental genetics by the 1995 Nobel Physiologiy laureates: E. LEWIS, C. NÜSSLEIN-VOLHARD and E. WIESCHAUS.

As this phenomenon is energy-dependent, it would be necessary to harmonize this concept with PRIGOGINE's one of dissipative structuration in systems faraway from equilibrium. The difference seems to be between some development limitations by pre-programming (for ex. genetic, technical, economic, or socio-cultural) and a nearly wholesale new programmation, after an overwhelming shattering of previous order through giant fluctuations induced by massive energy inputs.

A similar potential contradiction is latent in MARUYAMA's concepts of morphogenesis in systems which present "deviation- amplifying" processes (which could be – or not? equated to PRIGOGINE's giant fluctuations) and morphostasis in systems with mutual negative feedbacks.

Morphogenesis is system-constructive while morphostasis is system-stabilizing. But, if morphogenesis is not somehow constrained within channels (chreods), and limited in time, it becomes system-destructive, even if it may in some cases lead to the emergence of a more complex system.

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