propositions (Michael R. Genesereth)
Date: Mon, 2 May 1994 10:50:53 -0700
Message-id: <199405021750.AA13897@Sunburn.Stanford.EDU>
To: interlingua@ISI.EDU, kr-advisory@ISI.EDU, srkb@ISI.EDU
From: (Michael R. Genesereth)
Subject: propositions

I would like to make one correction to the report in John Sowa's recent
message.  Referring to me, John reported that I ``do not want to define
proposition as a built-in KIF type''.  This is not accurate, though I
understand how he got that impression.  I would be very happy to include
propositions in KIF; in fact, as early as the first meeting of the
knowledge sharing community, I proposed that we do so and offered a
proposal.  My reluctance to do so now stems from the following two

(1) From what I have heard on the interlingua mailing list and in private
conversations, propositions CAN BE HANDLED via an ontology, just as we
handle other important concepts (like those of algebra and frames).  I have
been receiving requests from all sides to minimize the size of KIF itself
and to leave ontologies to the ontology committee.  The presumption, as I
understand it, is that certain ontologies will grow up to be standards and
will be adopted by everyone; so, when this ontology of propositions is
complete, it will, in effect, become part of our interlingua (like the
ontologies of algebra and frames).

(2) I have not yet gotten the sense that there is a consensus on the nature
of propositions, i.e. the axioms that characterize them.  Therefore, I
think it would be counterproductive to try to add this notion into KIF at
this time, even if we felt it should not be treated as a separate ontology.
 My proposal is to ask the ontology committee to study the subject, get
some agreement, and then we can re-open the discussion of whether it should
become part of KIF itself.

In summary, I think propositions are very important indeed.  I use one
version of propositions in my own work.  But, they are described via an
ontology built on KIF.  I would be happy to compare my version to others
and participate in a discussion of what this ontology should be.