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From: tanner@osu-eddie.UUCP
Newsgroups: comp.ai
Subject: Re: Explanations in expert systems
Message-ID: <3300@osu-eddie.UUCP>
Date: Fri, 6-Mar-87 18:01:45 EST
Article-I.D.: osu-eddi.3300
Posted: Fri Mar  6 18:01:45 1987
Date-Received: Sun, 8-Mar-87 11:56:54 EST
References: <1800@ihuxv.ATT.COM>
Reply-To: tanner@osu-eddie.UUCP (Mike Tanner)
Organization: The Ohio State University, CIS Dept.
Lines: 43
Keywords: expert systems, ai, natural language

In article <1800@ihuxv.ATT.COM> arrgh@ihuxv.ATT.COM (Hill) writes:
>
>In real life, an expert system probably will not be used unless it possesses
>a sound explanation facility.  For most users, this does not mean merely 
>dumping rules or whatever, e.g., "the system is trying to satisfy
>rule-518", but 
>rather being able to turn the knowledge encoded in each unit of representation
>into meaningful natural language.
>

While I agree that spitting out rules is generally inadequate for
explanation I disagree that explanations *must* be in natural language.
For some kinds of explanation drawing and pointing is more useful.

"I think the wonkus is broken.  Try replacing it."
"Wonkus!?  What's that?"
"Take a look at the zweeble smasher.  See this gizmo?  That's the wonkus."

I'm not saying natural language is useless.  But the above interaction
would have taken a lot more words without the picture.  (With the
picture it might have needed no words at all.  But I don't know what a
zweeble smasher is, much less how to draw one.)  Sometimes a picture
really is worth a thousand words.

Keep in mind that when you talk about explanation as giving back rules
you're assuming expert systems are simple, flat rule-bases.  This is
not necessarily true.  If all your expert system knows is rules then:
	(a) the system isn't doing anything interesting 
	OR
	(b) you're actually using the rule language as a general
	    purpose programming language (because rules qua rules
	    don't give you the control features needed to navigate a
	    large knowledge base) 

In case (a), there's no need to worry about real world usefulness.  In
case (b), there should be no surprise that the rules themselves are
not informative explainers.  No more than a listing of code would, in
general, be an explanation of a program.

-- mike

ARPA:  tanner@ohio-state.arpa
UUCP:  ...cbosgd!osu-eddie!tanner