Self-organization refers to a process in which the internal organization of a system, normally an open system, increases automatically without being guided or managed by an outside source.
The most robust and unambiguous examples of self-organizing systems are from physics, where the concept was first noted. Self-organization is also relevant in chemistry, where it has often been taken as being synonymous with self-assembly. The concept of self-organization is central to the description of biological systems, from the subcellular to the ecosystem level. There are also cited examples of "self-organizing" behaviour found in the literature of many other disciplines, both in the sciences and the social sciences such as economics anthropology. Self-organization has also been observed in mathematical systems such as cellular automata.
Sometimes the notion of self-organization is conflated with that of the related concept of emergence. Properly defined, however, there may be instances of self-organization without emergence and emergence without self-organization, and it is not clear from the literature that the phenomenon are the same. The link between emergence and self-organization remains an active research question.
The idea that the dynamics of a system can tend, by themselves, to make it more orderly, has a long history. One of the first statements of this idea is Descartes, in the fifth part of his Discourse on Method, where he presents it hypothetically. Descartes further elaborated on the idea at great length in a book called Le Monde which was never published.
The ancient atomists (among others) had argued that a designing intelligence was unnecessary, but they generally argued that given enough time and space and matter, organization is bound to happen at some point, but not that there would be any tendency for this to happen.
What Descartes introduced was the idea that the ordinary laws of nature tend to produce organization. (For related history, see Avram Vartanian, From Descartes to Diderot.)
Starting with the 18th century naturalistss, there was a movement to try to understand the "universal laws or form" in order to explain the observed forms of living organisms. Because of its association with Lamarckism, these theories fell into disrepute until the early 20th century, where pioneers like D'Arcy Wentworth Thompson rescued it. The modern understanding is that there are indeed universal laws (coming from physics and chemistry) governing growth and form in biological systems.
More modernly, the term "self-organizing" seems to have been introduced in 1947 by psychiatrist and engineer, W. Ross Ashby. Self-organization as a word and concept was used by those associated with general systems theory in the 1960s, but was really taken up by physicists and people working on complex systems in the 1970s and 1980s, which is when it become much more widely used in the literature. (When queried with the keyword self-organ*, Dissertation Abstracts finds nothing before 1954, and only four total before 1970. There were 17 in the years 1971--1980; 126 in 1981--1990; and 593 in 1991--2000.)
The following list expands on the self-organization found in different disciplines. As the list grows, it becomes increasingly difficult to determine whether these phenomena are all fundamentally the same process, or the same label applied to several different processes. Self-organization, despite its intuitive simplicity as a concept, has proven notoriously difficult to define and pin down formally or mathematically.
It should also be noted that, the farther a phenomenon is removed from physics, the more controversial the idea of self-organization as understood by physicists becomes. Also, even when self-organization is clearly present, attempts at explaining it through physics or statistics are usually criticized as reductionistic. See holism, reductionism, emergence.
Similarly, when ideas about self-organization originate in, say, biology or social science, the farther one tries to take the concept into chemistry, physics or mathematics, the more resistance is encountered, usually on the grounds that it implies direction in fundamental physical processes. See teleology.
There are several broad classes of physical processes that can be described as self-organization. Such examples from physics include:
The idea of self-organization challenges the earlier, doctrine of ever-decreasing order which was based on philosophical generalization from the second law of thermodynamics. However, at the microscopic level, the two need not be in contradiction: it is possible for a closed system to gain macroscopic order whilst increasing its overall entropy, or for a system to reduce its entropy by interacting with external systems. More technically, some the system's degrees of freedom can become more ordered, even as the overall entropy increases. In many cases of biological self-assembly, for instance, the increasing organization of large molecules is more than compensated for by the increasing entropy of small molecules, especially water.
Since isolated systems cannot decrease their entropy, only open systems can exhibit self-organization. It is the flow of matter and energy through the system that allows the system to self-organize, and to exchange entropy with the environment. This is the basis of the theory of dissipative systems. Also, self-organization can only occur far away from thermodynamic equilibrium.
Self-organization in chemistry includes:
The following is an incomplete list of the diverse phenomena which have been described as "self-organizing" in biology.
As mentioned above, phenomenon from mathematics and computer science such as cellular automata, random graphs, and some instances of evolutionary computation and artificial life exhibit features of self-organization.
In particular the theory of random graphs has been used as a justification for self-organization as a general principle of complex systems.
The self-organizing behaviour of social animals and the self-organization of simple mathematical structures both suggest that self-organization should be expected in human society. Tell-tale signs of self-organization are usually statistical properties shared with self-organizing physical systems (see Zipf's law, power law, Pareto principle).
Examples abound in sociology, economics and anthropology.
Non-thermodynamic concepts of entropy and self-organization have been explored by many theorists. Cliff Joslyn and colleagues and their so-called "global brain" projects, and Marvin Minsky's "Society of Mind" idea, are examples of applications of these principles - see collective intelligence.
Donella Meadows, who codified twelve leverage points that a self-organizing system could exploit to organize itself, was one of a school of theorists who saw human creativity as part of a general process of adapting human lifeways to the planet and taking humans out of conflict with natural processes. See Gaia philosophy, deep ecology, ecology movement and Green movement for similar self-organizing ideals.
In alphabetical order
In chronological order
Introduction
History of the idea
Examples
Self-organization in physics
It is sometimes debated whether static systems deserve the label of "self-organizing".
Self-organization vs. entropy
Self-organization in chemistry
Self-organization in biology
Self-organization in mathematics and computer science
Self-organization in human society
In collective intelligence
References and links
See also
Bibliography
Non-technical
Technical works
External links
Sources used in article
