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    ELECTRONIC NEWSLETTER ON  REASONING ABOUT ACTIONS AND CHANGE        
Issue 99025             Editor: Erik Sandewall             6.10.1999
         Back issues available at http://www.etaij.org/rac/
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                    *********  TODAY  *********

Camilla Schwind today answers a question by Hector Geffner about her 
ETAI submitted article. (The concurrent discussion with Judea Pearl 
about the same article is calm for the moment).



              *********  ETAI PUBLICATIONS  *********

            ---  DISCUSSION ABOUT RECEIVED ARTICLES  ---

The following debate contributions (questions, answers, or comments)
have been received for articles that have been submitted to the ETAI and
which are presently subject of discussion. To see the full context,
for example, to see the question that a given answer refers to, or to
see the article itself or its summary, please use the web-page version 
of this Newsletter.

        ========================================================
        |  AUTHOR: Camilla Schwind
        |  TITLE:  Causality in Action Theories
        |  PAPER:  http://www.ep.liu.se/ea/cis/1999/004/
        |  REVIEW: http://www.ida.liu.se/ext/etai/ra/rac/018/
        ========================================================

Answer to Hector Geffner, who raised the following questions:

1. are the inference rules considered particularly relevant to causal 
   reasoning? 

2.  are there significant inference rules that are not in the list? 

First, let me point out that my main purpose has been to compare
existing approaches and not to define postulates. I prefer the term
"comparison criteria". This is what I formulated and NOT postulates.
 
ad 1. The criteria  have been formulated with respect to the comparison
task of several action theories which integrated causality; in this
respect they are relevant as I think.

ad 2. It happened to me to use other  criteria, which  are not in the
list and which are more related to causality and update. Since  NO one
of the formalisms I reported could be compared along those criteria, I
found it moderately interesting to include them.  
 
I think indeed that causality is a nonmonotonic inference relation (see
my criterion 1). But there are properties of nonmonotonic inference
which I reject for causlity (e.g. reflexivity). 

Camilla Schwind

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