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An adaptive system is a set of interacting or interdependent entities, real or abstract, forming an integrated whole that together are able to respond to environmental changes or changes in the interacting parts, in a way analogous to either continuous physiological homeostasis or evolutionary adaptation in biology. Feedback loops represent a key feature of adaptive systems, such as ecosystems and individual organisms; or in the human world, communities, organizations, and families.

Artificial adaptive systems include robots with control systems that utilize negative feedback to maintain desired states.

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The law of adaptationEdit

The law of adaptation can be stated informally as:

Every adaptive system converges to a state in which all kind of stimulation ceases.[1]

Formally, the law can be defined as follows:

Given a system  , we say that a physical event   is a stimulus for the system   if and only if the probability   that the system suffers a change or be perturbed (in its elements or in its processes) when the event   occurs is strictly greater than the prior probability that   suffers a change independently of  :

 

Let   be an arbitrary system subject to changes in time   and let   be an arbitrary event that is a stimulus for the system  : we say that   is an adaptive system if and only if when t tends to infinity   the probability that the system   change its behavior   in a time step   given the event   is equal to the probability that the system change its behavior independently of the occurrence of the event  . In mathematical terms:

  1. -  
  2. -  

Thus, for each instant   will exist a temporal interval   such that:

 

Benefit of self-adjusting systemsEdit

In an adaptive system, a parameter changes slowly and has no preferred value. In a self-adjusting system though, the parameter value “depends on the history of the system dynamics”. One of the most important qualities of self-adjusting systems is its “adaptation to the edge of chaos” or ability to avoid chaos. Practically speaking, by heading to the edge of chaos without going further, a leader may act spontaneously yet without disaster. A March/April 2009 Complexity article further explains the self-adjusting systems used and the realistic implications.[2] Physicists have shown that adaptation to the edge of chaos occurs in almost all systems with feedback.[3]

PractopoiesisEdit

How do various types of adaptations interact in a living system? Practopoiesis, a term due to its originator Danko Nikolić, is a reference to a hierarchy of adaptation mechanisms answering this question. The adaptive hierarchy forms a kind of a self-adjusting system in which autopoiesis of the entire organism or a cell occurs through a hierarchy of allopoietic interactions among components.[4] This is possible because the components are organized into a poietic hierarchy: adaptive actions of one component result in creation of another component. The theory proposes that living systems exhibit a hierarchy of a total of four such adaptive poietic operations:

   evolution (i) → gene expression (ii) → non gene-involving homeostatic mechanisms (anapoiesis) (iii) → final cell function (iv)

As the hierarchy evolves towards higher levels of organization, the speed of adaptation increases. Evolution is the slowest; the final cell function is the fastest. Ultimately, practopoiesis challenges current neuroscience doctrine by asserting that mental operations primarily occur at the homeostatic, anapoietic level (iii) — i.e., that minds and thought emerge from fast homeostatic mechanisms poietically controlling the cell function. This contrasts the widespread belief that thinking is synonymous with neural activity (i.e., with the 'final cell function' at level iv).

Each slower level contains knowledge that is more general than the faster level; for example, genes contain more general knowledge than anapoietic mechanisms, which in turn contain more general knowledge than cell functions. This hierarchy of knowledge enables the anapoietic level to directly activate concepts, which are the most fundamental ingredient for the emergence of the mind.

See alsoEdit

NotesEdit

  1. ^ José Antonio Martín H., Javier de Lope and Darío Maravall: "Adaptation, Anticipation and Rationality in Natural and Artificial Systems: Computational Paradigms Mimicking Nature" Natural Computing, December, 2009. Vol. 8(4), pp. 757-775. doi
  2. ^ Hübler, A. & Wotherspoon, T.: "Self-Adjusting Systems Avoid Chaos". Complexity. 14(4), 8 – 11. 2008
  3. ^ Wotherspoon, T.; Hubler, A. (2009). "Adaptation to the edge of chaos with random-wavelet feedback". J Phys Chem A. 113 (1): 19–22. doi:10.1021/jp804420g. PMID 19072712.
  4. ^ Danko Nikolić (2015). "Practopoiesis: Or how life fosters a mind". Journal of Theoretical Biology. 373: 40–61. arXiv:1402.5332. doi:10.1016/j.jtbi.2015.03.003. PMID 25791287.

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