[1]Principia Cybernetica Web

                                     Irritability

   We start with the most primitive animals. Unlike plants, they have an apparatus
   that allows them to take actions of their own and to control those actions
   through irritation of nerve cells. Take a hydra. It has two layers of cells
   containing muscle fibers which contract when irritated, and nerve cells
   (receptors) which can irritate and pass irritation to muscle fibers. If a hydra
   is pricked with a needle it squeezes itself into a tiny ball. The emergence of
   this apparatus is a metasystem transition (MST) from the stage of primitive
   plants where there are no self-induced actions. This MST is defined by the
   formula:

   cell-irritation = control of actions

   Indeed, we see in the hydra all elements of the [2]control scheme. The
   "representation" corresponds to the receptors in the ectoderm which get irritated
   and pass irritation to muscle fibers; The "agent" stands for the muscle fibers,
   which act when irritated.
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   [3]Copyright© 2003 Principia Cybernetica - [4]Referencing this page

   Author
   V. [5]Turchin,

   Date
   Apr 23, 2003 (modified)
   Sep 1991 (created)

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References

   1. LYNXIMGMAP:http://pespmc1.vub.ac.be/IRRIT.html#PCP-header
   2. http://pespmc1.vub.ac.be/CONTROL.html
   3. http://pespmc1.vub.ac.be/COPYR.html
   4. http://pespmc1.vub.ac.be/REFERPCP.html
   5. http://pespmc1.vub.ac.be/TURCHIN.html
   6. http://pespmc1.vub.ac.be/DEFAULT.html
   7. http://pespmc1.vub.ac.be/MSTT.html
   8. http://pespmc1.vub.ac.be/HISTEVOL.html
   9. http://pespmc1.vub.ac.be/COGNEVOL.html
  10. http://pespmc1.vub.ac.be/COGNEVOL.html
  11. http://pespmc1.vub.ac.be/REFLEX.html
  12. http://pespmc1.vub.ac.be/MAKANNOT.html
  13. http://pespmc1.vub.ac.be/hypercard.acgi$annotform?

[USEMAP]
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   1. http://pespmc1.vub.ac.be/DEFAULT.html
   2. http://pespmc1.vub.ac.be/HOWWEB.html
   3. http://pcp.lanl.gov/IRRIT.html
   4. http://pespmc1.vub.ac.be/IRRIT.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#IRRIT
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