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Re: Agenda for RDFCore WG Telecon 2002-07-26 (rdfms-assertion)

From: Graham Klyne <Graham.Klyne@MIMEsweeper.com>
Date: Wed, 31 Jul 2002 09:40:26 +0100
Message-Id: <>
To: Dan Connolly <connolly@w3.org>, Pat Hayes <phayes@ai.uwf.edu>
Cc: w3c-rdfcore-wg@w3.org, Eric Miller <em@w3.org>

At 06:53 PM 7/30/02 -0500, Dan Connolly wrote:
>On Tue, 2002-07-30 at 18:31, pat hayes wrote:
> > so even if C had intended to
> > bad-mouth me, B's stupidity would have thwarted him.
> >
> > Hope this helps.
>Very, very much, it helps while away the time pleasantly ;-)
>And yes, it helps on rdfms-assertion, too, though
>it may need to be edited just a touch before
>release in a WD, no?

Pat, as usual, your words illustrate the point very vividly.  I expect I 
could rework it to a more professionally acceptable form, even if it would 
lose some of it's colour in the process (and probably also some of its 
illustrative power).

Following input from Jos, I've reworked some of those sections to use some 
wording based on an earlier contribution of Pat's, whose overall effect is 
to reduce the volume of text without (I think) any loss of meaning (see 
excerpt below).

So my questions are:
(a) is the proposed rewording (below) any clearer?
(b) should I work in the example -- I'm thinking an edited version might 
appear as a new section 2.3.5, illustrating what has gone before.

I think final resolution of this could be left to a future WD round?


Current new text for sections 2.3.3, 2.3.4:

2.3.3 Interaction between social and formal meaning

Using RDF, 'received meaning' can be characterized as the social meaning of 
any logical consequences.

If you publish a graph G and G logically entails G', and we interpret G' 
using the same social conventions that everyone agrees could be reasonably 
used to interpret G, then you are asserting that content of G' as well.

Human publishers of RDF content commit themselves to the 
mechanically-inferred social obligations. The machines doing the inferences 
aren't expected to know about all these social conventions and obligations.

The social conventions used to interpret a graph may include assumed 
truths, for which no logical derivation is available, and socially accepted 
consequences whose rules of deduction are embedded in arbitrary decision- 
making processes.

Semantic web vocabulary gains currency through use, so also do semantic web 
deductionshave force through social acceptance. Semantic web deduction 
operates in a combination of logical and social (non-logical) dimensions.

To support logical entailments, formal RDF meaning is based on a model 
theory (see section 2.3.1). The notion of truth is crucial: a possible 
world may correspond to some RDF if and only if the RDF statement is true 
in that world.

The RDF core language provides a way to make simple formal assertions, with 
no machinery for formalizing allowable inferences. Inferences are performed 
by processes, embedded in software implentations, whose validity is not 
formally demonstrable, and must be assumed or trusted to be socially 
acceptable. It is expected that semantic web languages layered on RDF will 
give formal expression to allowable inferences, thus to allow provable 
deductions by generic software modules to replace individual ad-hoc 

2.3.4 Implications of asserting RDF

When an RDF graph is asserted in the web, its publisher is saying something 
about their view of the world. (The mechanism for deciding whether or not a 
graph is asserted is not defined here, but it is presumed that the 
publisher's intent will be clear in some way.)

When a user invokes an application, there is also a social and technical 
context of invocation that determines some set of RDF assertions that will 
be assumed to be true: the application itself, and any RDF files that are 
passed to it. Garbage-in, garbage-out applies: if the initial assumed facts 
are wrong or meaningless, the results will have little value. No specfic 
mechanisms for deciding or evaluating the validity of any such assertions 
are defined here.

Noting that there is no single human opinion about the truth of some 
statements, the graph may further contain commentary for human interpreters 
to indicate the realm of human interpretation that should be applied. This 
means a graph may contain "defining information" that is opaque to logical 
reasoners. This information may be used by human interpreters of RDF 
informaton, or programmers writing software to perform specialized forms of 
deduction in the Semantic Web.

Graham Klyne
Received on Wednesday, 31 July 2002 05:28:13 UTC

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