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From: coffee@aero.UUCP
Newsgroups: comp.ai
Subject: Re: dear abby....
Message-ID: <8106@aero.ARPA>
Date: Tue, 3-Mar-87 12:54:03 EST
Article-I.D.: aero.8106
Posted: Tue Mar  3 12:54:03 1987
Date-Received: Fri, 6-Mar-87 04:43:10 EST
References: <178@arcsun.UUCP> <3269@osu-eddie.UUCP>
Reply-To: coffee@aero.UUCP (Peter C. Coffee)
Organization: The Aerospace Corporation, El Segundo, CA
Lines: 26
Keywords: justification in expert systems
Summary: "Expert System" <> "Useful Program"

In article <3269@osu-eddie.UUCP> tanner@osu-eddie.UUCP (Mike Tanner) writes:

>If all you want is an expert system, ie, a system which gets
>right answers, then you're back to utility arguments for explanation.

I agree with everything else Mike said about this issue, but it seems to
me that the label "expert system" _should_ mean something _more_ than "a
system that gets right answers." We've had useful programs, implicitly
applying "expert" knowledge, for a long time: the new label should reflect
new capabilities. Hayes-Roth et alia, in _Building_Expert_Systems_, say the
following:

"...[E]xpert systems differ from the broad class of AI tasks in several 
respects...they employ self-knowledge to reason about their own inference
processes and provide explanations or justifications for conclusions
reached."

This is one of the milestone texts in the field, and definitions are useful
things: it seems to me that disputes over whether explanation is "needed"
before you can call it an expert system are missing the point. We _have_ what
seems to me to be a mainstream definition for the term; if we want
to talk about a system that _doesn't_ do explanation, can't we just call
it a computer program (or a parser, or a pattern recognizer, or whatever)
instead of trying to stretch the popular label to fit it?

Constructively, I hope, Peter C.