Self-organization

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Self-organization is a process in which the internal organization of a system, normally an open system, increases in complexity without being guided or managed by an outside source. Self-organizing systems typically (though not always) display emergent properties.

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[edit] Overview

Cellular automaton here running Stephen Wolfram's "rule 30", a mathematical construct displaying self-organization
Cellular automaton here running Stephen Wolfram's "rule 30", a mathematical construct displaying self-organization

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 natural sciences and the social sciences such as economics or 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 clear from the literature that the phenomena are not the same. The link between emergence and self-organization remains an active research question.

Self-organization usually relies on four basic ingredients:

  1. Positive feedback
  2. Negative feedback
  3. Balance of exploitation and exploration
  4. Multiple interactions

[edit] History of the idea

The idea that the dynamics of a system can tend by themselves to increase the inherent order of a system has a long history. One of the earliest statements of this idea was by the philosopher 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 that was never published.

The ancient atomists (among others) believed that a designing intelligence was unnecessary, arguing that given enough time and space and matter, organization was ultimately inevitable, although there would be no preferred 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 Aram Vartanian, Diderot and Descartes).

Beginning with the 18th century naturalists a movement arose that sought to understand the "universal laws of form" in order to explain the observed forms of living organisms. Because of its association with Lamarckism, their ideas fell into disrepute until the early 20th century, when pioneers such as D'Arcy Wentworth Thompson revived them. The modern understanding is that there are indeed universal laws (arising from fundamental physics and chemistry) that govern growth and form in biological systems.

The term "self-organizing" seems to have been first introduced in 1947 by the psychiatrist and engineer W. Ross Ashby. It was taken up by the cyberneticians Heinz von Foerster, Gordon Pask, Stafford Beer and Norbert Wiener himself in the second edition of his "Cybernetics: or Control and Communication in the Animal and the Machine" (MIT Press 1961). Self-organization as a word and concept was used by those associated with general systems theory in the 1960s, but did not become commonplace in the scientific literature until its adoption by physicists and researchers in the field of complex systems in the 1970s and 1980s.

(As an indication of the increasing importance of this concept, when queried with the keyword self-organ*, Dissertation Abstracts finds nothing before 1954, and only four entries before 1970. There were 17 in the years 1971--1980; 126 in 1981--1990; and 593 in 1991--2000.)

[edit] Examples

The following list summarizes and classifies the instances of 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, and it is entirely possible that any precise definition might not include all the phenomena to which the label has been applied.

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.

[edit] Self-organization in physics

There are several broad classes of physical processes that can be described as self-organization. Such examples from physics include:

  • self-organizing dynamical systems: complex systems made up of small, simple units connected to each other usually exhibit self-organization.
  • In spin foam system and loop quantum gravity that was proposed by Lee Smolin. The main idea is that the evolution of space in time should be robust in general. Any fine-tuning of cosmological parameters weaken the independency of the fundamental theory. Philosophically, it can be assumed that in the early time, there has not been any agent to tune the cosmological parameters. Smolin and his colleagues in a series of works show that, based on the loop quantization of spacetime, in the very early time, a simple evolutionary model (similar to the sand pile model) behaves as a power law distribution on both the size and area of avalanche.
    • Although, this model, which is restricted only on the frozen spin networks, exhibits a non-stationary expansion of the universe. However, it is the first serious attempt toward the final ambitious goal of determining the cosmic expansion and inflation based on a self-organized criticality theory in which the parameters are not tuned, instead they are determined from within the complex system; Self-organized theory in quantum gravity.

[edit] Self-organization vs. entropy

The idea of self-organization challenges an earlier paradigm of ever-decreasing order which was based on a philosophical generalization from the second law of thermodynamics in statistical thermodynamics where entropy is envisioned as a measure of the statistical "disorder" at a microstate level. However, at the microscopic or local level, the two need not be in contradiction: it is possible for a system to reduce its entropy by transferring it to its environment.

In open systems, 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 structures. Ilya Prigogine noted that self-organization can only occur far away from thermodynamic equilibrium.

It would appear that, since isolated systems cannot decrease their entropy, only open systems can exhibit self-organization. However, such a system can gain macroscopic order while increasing its overall entropy. Specifically, a few of the system's macroscopic degrees of freedom can become more ordered at the expense of microscopic disorder.

In many cases of biological self-assembly, for instance metabolism, the increasing organization of large molecules is more than compensated for by the increasing entropy of small molecules, especially water. At the level of a whole organism and over longer time scales, though, biological systems are open systems feeding from the environment and dumping waste into it.

At a more global level, the Earth approximates a closed system in that little matter is exchanged with the surrounding solar system. Life and evolution can occur because of the local input of primarily solar energy, while the global entropy of the solar system as a whole continues to increase towards a cold, dead endpoint. In that sense, life is "swimming upstream" against the larger thermodynamic trends only because of direct sunlight.

[edit] Self-organization in chemistry

Self-organization in chemistry includes:

  1. molecular self-assembly
  2. reaction-diffusion systems and oscillating chemical reactions
  3. autocatalytic networks (see: autocatalytic set)
  4. liquid crystals

[edit] Self-organization in biology

The following is an incomplete list of the diverse phenomena which have been described as "self-organizing" in biology.

  1. spontaneous folding of proteins and other biomacromolecules,
  2. formation of lipid bilayer membranes,
  3. homeostasis (the self-maintaining nature of systems from the cell to the whole organism)
  4. morphogenesis, or how the living organism develops and grows. See also embryology.
  5. the coordination of human movement, e.g. seminal studies of bimanual coordination by Kelso
  6. the creation of structures by social animals, such as social insects (bees, ants, termites), and many mammals
  7. flocking behaviour (such as the formation of flocks by birds, schools of fish, etc.)
  8. the origin of life itself from self-organizing chemical systems, in the theories of hypercycles and autocatalytic networks
  9. the organization of Earth's biosphere in a way that is broadly conducive to life (according to the controversial Gaia hypothesis)

Evolution is, in a limited sense, the self-organization of a genome but it does not represent self-organization for any one organism. In the very long term, later species seem to be "more organized" than prior, lower life forms. The genome does not necessarily become more organized; it simply becomes more viable. For example, if discarding some well-organized knowledge from the genome somehow makes the resulting organisms more viable (e.g. discarding a specialized defense against some then-extinct infectious agent or predator), then statistically that less-organized genome will be the outcome in later generations that survive and replicate even though it is less organized.

[edit] Self-organization in mathematics and computer science

As mentioned above, phenomena 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 swarm robotics, self-organization is used to produce emergent behavior.

In particular the theory of random graphs has been used as a justification for self-organization as a general principle of complex systems.

[edit] Self-organization in human society

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 such as Critical Mass (bicycle), herd behaviour, groupthink and others, abound in sociology, economics, behavioral finance and anthropology. Interactive models are found on this link.

In social theory the concept of self-referentiality has been introduced as a sociological application of self-organization theory by Niklas Luhmann (1984). For Luhmann the elements of a social system are self-producing communications, i.e. a communication produces further communications and hence a social system can reproduce itself as long as there is dynamic communication. For Luhmann human beings are sensors in the environment of the system. Luhmann put forward a functional theory of society.

In recent years another version of self-organization in social systems has been introduced by interpreting the relationship of social structures and social practices/actions as dialectical (e.g. Christian Fuchs 2003a,b,c). Such concepts can be found in the works of e.g. Anthony Giddens and Pierre Bourdieu. In such theories social structures enable and constrain social actions and are produced and reproduced by social actions. This process can be interpreted as a dynamic self-organization process. Social systems in this sense are re-creative, they permanently produce and reproduce actions and structures. Such theories are more action-based and consider self-organization also as a critical notion in the sense of self-management, self-determination, grassroots organization, and participatory democracy (Christian Fuchs 2006).

Self-organization in human and computer networks can give rise to a decentralized, distributed, self-healing system, protecting the security of the actors in the network by limiting the scope of knowledge of the entire system held by each individual actor. The Underground Railroad is a good example of this sort of network. The networks that arise from drug trafficking exhibit similar self-organizing properties. (Parallel examples exist in the world of privacy-preserving computer networks, e.g. [Tor].) In each case, the network as a whole exhibits distinctive synergistic behavior through the combination of the behaviors of individual actors in the network. Usually the growth of such networks is fueled by an ideology or sociological force that is adhered to or shared by all participants in the network.

[edit] In economics

In economics, a market economy is sometimes said to be self-organizing. Friedrich Hayek coined the term catallaxy to describe a "self-organizing system of voluntary co-operation," in regard to capitalism. Advocates of laissez-faire hold that a centrally-planned economy makes the system less organized and less efficient. By contrast, some socialist economists consider that market failures are so significant that self-organization produces bad results and that the state should direct production and pricing. Many economists adopt an intermediate position that and recommend a mixture of market economy and command economy characteristics (sometimes called a mixed economy).

[edit] In collective intelligence

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.

[edit] See also

[edit] References

[edit] Non-technical

In alphabetical order

[edit] Technical works

In chronological order

  • D'Arcy Thompson, On Growth and Form, Cambridge University Press, 1917 (1992 Dover Publications edition, ISBN 0-486-67135-6)
  • W. Ross Ashby, "Principles of the Self-Organizing Dynamic System", Journal of General Psychology (1947), volume 37, pages 125--128
  • Gordon Pask, The cybernetics of evolutionary processes and of self organizing systems, 3rd. International Congress on Cybernetics, Namur, Association Internationale de Cybernetique 1961
  • Heinz Von Foerster and George W. Zopf, Jr. (eds.), Principles of Self-Organization (Sponsored by Information Systems Branch, U.S. Office of Naval Research), 1962
  • W. Ross Ashby, Design for a Brain, Chapman & Hall, 2nd edition, 1966 ISBN 0-412-20090-2
  • Myrna L. Estep, Self-Organizing Natural Intelligence: Issues of Knowing, Meaning, and Complexity, Springer-Verlag 2006 [ISBN 1-4020-5275-8]
  • Gregoire Nicolis and Ilya Prigogine Self-Organization in Non-Equilibrium Systems, 1977, Wiley, ISBN 0-471-02401-5
  • Manfred Eigen and Peter Schuster The Hypercycle: A principle of natural self-organization, 1979, Springer ISBN 0-387-09293-5
  • Hermann Haken Synergetics: An Introduction. Nonequilibrium Phase Transition and Self-Organization in Physics, Chemistry, and Biology, Third Revised and Enlarged Edition, 1983, Springer-Verlag ISBN 0-387-12356-3
  • J. Doyne Farmer et al. (editors), Evolution, Games, and Learning: Models for Adaptation in Machines and Nature. Physica D 22 (1986).
  • Stuart Kauffman, Origins of Order: Self-Organization and Selection in Evolution Oxford University Press, 1993, ISBN 0-19-507951-5.
  • J. A. Scott Kelso "Dynamic Patterns: The self-organization of brain and behavior", 1995, Paperback Edition, 1997, The MIT Press, Cambridge, MA. ISBN 0-262-11200-0
  • Paul Krugman, The Self-Organizing Economy, Cambridge, Mass., and Oxford: Blackwell Publishers, 1996, ISBN 1-55786-698-8, ISBN 1-55786-699-6
  • Henrik Jeldtoft Jensen, Self-Organized Criticality: Emergent Complex Behaviour in Physical and Biological Systems, Cambridge Lecture Notes in Physics 10, Cambridge University Press, 1998, ISBN 0-521-48371-9
  • Müller, J.-A., Lemke, F., Self-Organizing Data Mining. (2000), ISBN 3-89811-861-4
  • Scott Camazine, Jean-Louis Deneubourg, Nigel R. Franks, James Sneyd, Guy Theraulaz, Eric Bonabeau (editors) Self-Organization in Biological Systems, 2001, Princeton Univ Press, ISBN 0-691-01211-3
  • Carlos Gershenson and Francis Heylighen. "When Can we Call a System Self-organizing?" In Banzhaf, W, T. Christaller, P. Dittrich, J. T. Kim, and J. Ziegler, Advances in Artificial Life, 7th European Conference, ECAL 2003, Dortmund, Germany, pp. 606-614. LNAI 2801. Springer. arXiv nlin/0303020.
  • K. Yee, "Ownership and Trade from Evolutionary Games," International Review of Law and Economics, 23.2, 183-197 (2003) PDF file.
  • Alex Kentsis, Self-organization of biological systems: Protein folding and supramolecular assembly, Ph.D. Thesis, New York University, 2004, (UMI ProQuest), ISBN 978-0-496-68098-6
  • Tom De Wolf, Tom Holvoet, Emergence Versus Self-Organisation: Different Concepts but Promising When Combined, In Engineering Self Organising Systems: Methodologies and Applications, Lecture Notes in Computer Science, volume 3464, pp 1-15, 2005, (download here)
  • Christian Prehofer, Christian Bettstetter, Self-Organization in Communication Networks: Principles and Design Paradigms, IEEE Communications Magazine, July 2005.
  • A. Bejan, Shape and Structure, from Engineering to Nature , Cambridge University Press, Cambridge, UK, 2000m 324 p. ISBN 0-521-79388-2
  • Korotayev A., Malkov A., Khaltourina D. Introduction to Social Macrodynamics: Compact Macromodels of the World System Growth. Moscow: URSS, 2006. ISBN 5-484-00414-4 [1].
  • Ricard V. Solé and Jordi Bascompte, Selforganization in Complex Ecosystems, Princeton U. Press, 2006.
  • Norbert Wiener, The mathematics of self-organising systems. Recent developments in information and decision processes, Macmillan, N. Y., 1962.

[edit] External links

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