Re: Copy of note to Elizabeth Fong
Message-id: <>
Date: Thu, 1 Apr 1993 15:01:10 +0000
To:, interlingua@ISI.EDU, kr-advisory@ISI.EDU, srkb@ISI.EDU,
        sowa <>
Subject: Re: Copy of note to Elizabeth Fong
Quick comment on these issues of intertranslatability. While I agree with
most of what John Sowa says here, I think there is a danger of confusion
bewteen two rather different senses of 'intertranslation'.  One treats the
languages as descriptive languages with some kind of extensional meaning.
Thinking of O_O languages as descriptive languages in this way is within
the krep tradition of AI; in this tradition, O_O notation is largely
intertranslateable with logical languages and network languages, in ways
that have been well understood now for over a decade. However, many O_O
languages, such as C++, are often thought of as programming languages,
whose primary function is to specify computational behavior. (Logic itself
can be thought of this way, and then its called Prolog (to oversimplify
somewhat)). But these are rather different  ways of thinking, and its not
at all obvious that the same kinds of semantics are appropriate to them.
For example, in the first way of thinking, the 'objects' in a semantic
domain might be whatever is the intended subjectmatter of the database; but
in the second way of thinking, an object is typically a computational
object, the encoding of a computational process of some kind. 

The tension between these two ways of thinking about expressive languages -
the descriptive and the computational - has been present now for a long
time and is not going to suddenly vanish. I raise the issue only to warn
against the danger of misunderstanding.  A simple diagnostic might be to
ask whether the way one is thinking about the meaning of the language
depends in any way upon any kind of computational state. If not, it is
being treated as a descriptive language; if so, as a computational

Hope this generates more light than heat. Feedback, including disagreement,

Pat Hayes

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