[1]Principia Cybernetica Web

                                   Order from noise

   Order from noise, which was first proposed by [2]Heinz von Foerster, is a special
   case of [3]the principle of selective variety: noise or random perturbations will
   help a self-organizing system to find more stable states in its fitness landscape
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   In the [4]fitness landscape representation all [5]attractors are not equal: those
   with a higher fitness are in a sense "better" than the others. For
   self-organizing systems, "better" or "[6]fitter" usually means "more stable" or
   "with more potential for growth". However, the dynamics implied by a fitness
   landscape does not in general lead to the overall fittest state: the system has
   no choice but to follow the path of steepest descent. This path will in general
   end in a local minimum of the potential, not in the global minimum.

   Apart from changing the fitness function, the only way to get the system out of a
   local minimum is to add a degree of indeterminism to the dynamics, that is, to
   give the system the possibility to make transitions to states other than the
   locally most fit one. This can be seen as the injection of "noise" or random
   perturbations into the system, which makes it deviate from its preferred
   trajectory. Physically, this is usually the effect of outside perturbations (e.g.
   vibrations, or shaking of the system) or of intrinsic indeterminacy (e.g. thermal
   or quantum fluctuations, or simply unknown factors that have not been
   incorporated into the state description). Such perturbations can "push" the
   system upwards, towards a higher potential. This may be sufficient to let the
   system escape from a local minimum, after which it will again start to descend
   towards a possibly deeper valley.

   In general, the deeper the valley, the more difficult it will be for a
   perturbation to make a system leave that valley. Therefore, noise will in general
   make the system move out of the more shallow, and into the deeper valleys. Thus,
   noise will in general increase fitness. The stronger the noise the more the
   system will be able to escape the relatively shallow valleys, and thus reach a
   potentially deeper valley. However, a system with noise will never be able to
   really settle down in a local or global minimum, since whatever level of fitness
   it reaches it will still be perturbed and pushed into less fit states.

   The most effective use of noise to maximize self-organization is to start with
   large amounts of noise which are then gradually decreased, until the noise
   disappears completely. The initially large perturbations will allow it to escape
   all local minima, while the gradual reduction will allow it to settle down in
   what is hopefully the deepest valley. This is the principle underlying annealing,
   the hardening of metals by gradually reducing the temperature, thus allowing the
   metal molecules to settle in the most stable crystalline configuration. The same
   technique applied to computer models of self-organization is called simulated
   annealing.
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   [7]Copyright© 1999 Principia Cybernetica - [8]Referencing this page

   Author
   F. [9]Heylighen,

   Date
   Dec 2, 1999

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References

   1. LYNXIMGMAP:http://pespmc1.vub.ac.be/ORDNOISE.html#PCP-header
   2. http://pespmc1.vub.ac.be/CSTHINK.html#Foerster
   3. http://pespmc1.vub.ac.be/SELVAR.html
   4. http://pespmc1.vub.ac.be/FITLANDS.html
   5. http://pespmc1.vub.ac.be/ATTRACTO.html
   6. http://pespmc1.vub.ac.be/FITNESS.html
   7. http://pespmc1.vub.ac.be/COPYR.html
   8. http://pespmc1.vub.ac.be/REFERPCP.html
   9. http://pespmc1.vub.ac.be/HEYL.html
  10. http://pespmc1.vub.ac.be/DEFAULT.html
  11. http://pespmc1.vub.ac.be/MSTT.html
  12. http://pespmc1.vub.ac.be/EVOLUT.html
  13. http://pespmc1.vub.ac.be/SELFORG.html
  14. http://pespmc1.vub.ac.be/FITLANDS.html
  15. http://pespmc1.vub.ac.be/RKSELECT.html
  16. http://pespmc1.vub.ac.be/MAKANNOT.html
  17. http://pespmc1.vub.ac.be/hypercard.acgi$annotform?

[USEMAP]
http://pespmc1.vub.ac.be/ORDNOISE.html#PCP-header
   1. http://pespmc1.vub.ac.be/DEFAULT.html
   2. http://pespmc1.vub.ac.be/HOWWEB.html
   3. http://pcp.lanl.gov/ORDNOISE.html
   4. http://pespmc1.vub.ac.be/ORDNOISE.html
   5. http://pespmc1.vub.ac.be/SERVER.html
   6. http://pespmc1.vub.ac.be/hypercard.acgi$randomlink?searchstring=.html
   7. http://pespmc1.vub.ac.be/RECENT.html
   8. http://pespmc1.vub.ac.be/TOC.html#ORDNOISE
   9. http://pespmc1.vub.ac.be/SEARCH.html