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C00002 00002	Rule-governed behavior dates back to primitive games and codes of law,
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Rule-governed behavior dates back to primitive games and codes of law,
but the idea of rule-based COMPUTATION arose quite recently.
Early in this century, Post defined production rule systems formally,
and employed them as abstract models of computation.  
Later researchers
found that the same methodology was useful for modelling some
elementary cognitive tasks, like
duplicating the results of psychological experiments on memory
recall.  By the time large AI rule-based systems were being
designed, they'd already inherited a wealth of stylistic constraints
from the formalists and the psychologists. In ohter words, when you
see or hear details of some rule-based system, you may observe many
design constraints which seem to be arbitrary; most of them ARE,
being nothing but historical accidents.  For instance, the
insistance that all state information be sqeezed into a single linear 
string of tokens, or the insistance that the IF part of a rule do
nothing more complicated than pattern-matching into that string of tokens.