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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 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.
Copyright© 2003 Principia Cybernetica -
Referencing this page
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Author
V. Turchin,
Date
Apr 23, 2003 (modified)
Sep 1991 (created)
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