- From: Richard Cyganiak <richard@cyganiak.de>
- Date: Sun, 8 Feb 2009 22:57:53 +0000
- To: rick <rick@rickmurphy.org>
- Cc: semantic-web@w3.org
On 8 Feb 2009, at 18:11, rick wrote: > As I have written before, the model theory on which the semantic web > is based is defined in Alfred Tarski's Semantic Conception of Truth. Rick, that's overstating the role of model theory on the Semantic Web. The formal semantics of RDF, as defined in [1], are based on model theory. But a lot of the deployed usage of RDF considers it simply as a distributed graph data model, and ignores (or even violates) the model theoretic semantics. Various non-RDF technologies, such as Topic Maps or microformats are often lumped under the Semantic Web umbrella as well. So, only a particular part of the Semantic Web technology portfolio is based on model theory. I agree, however, that it's the part that can benefit most from armchair philosophizing. Have fun, Richard [1] http://www.w3.org/TR/rdf-mt/ > Briefly, Tarski defines truth in terms of material adequacy and > formal correctness. Note that Tarski does not define meaning, only > truth. I think everyone would agree that material adequacy applies > only to resources can be dereferenced and that it is formal > correctness that provides the foundation for inference. > > So what can we say about meaning on the semantic web? We can say > that URIs are definitions, but we need to be clear that meaning is > not definition. Quine writes about this in Two Dogmas of Empiricism. > Live meaning as referenced above implies interpretation. > > The question then is whether inference is interpretation. I believe > inference as used on the semantic web is necessary, but not > sufficient for interpretation. Interpretation as it applies to > meaning implies abduction as well as induction and deduction. > Inference on the semantic web implies formal correctness and truth. > > It's not clear whether the semantic web lacks this design principle > intentionally, but without this design principle, the semantic web > will lag the web in its utility. > > As a compelling example, consider how the web serves as a meme pool > for cultural transmission. How would we expect the semantic web to > serve as a meme pool with dead languages ? > >> I think this worry becomes more so as axioms and systems of axioms >> become more complicated. (I just about see similarities between >> OWL2 and the Shorter Latin Primer I had at high school). >> >> A term which is too tightly nailed down in its relationship to >> other terms has been dug into an early grave. Having fixed its >> meaning, as our world moves on, the term will become useless. >> > A semiotic domain is a good next step to start developing this > flexibility. >> The trick, in natural language, is that the meaning of terms is >> somewhat loose, and moves with the times, while still having some >> limits. >> This looseness of definition gives rise to some misunderstandings >> (aka interoperability failures), but not too many, we hope. >> >> > Pragmatics is a step after semiotics. >> So I wonder, as some people try to describe some part of their >> world with great precision, using the latest and greatest formal >> techniques, just how long that way of describing the world will >> last. Maybe there is a role in such precision in allowing us to be >> clear about differences of opinion --- but it doesn't seem to me to >> be a good foundation for building knowledge. >> >> > While I agree that we need to recognize the limitations of where we > are today, I think Tarski's Semantic Conception of Truth is a pretty > good place to start. We also need to recognize the challenges of > moving along the path to live meaning. > > If you're looking for some fun reading, Robert Kent has already > defined the Information Flow Framework which parameterizes > languages, logics, models and theories into a much more flexible > approach than the semantic web. But hold onto your towel ... > > http://www.ontologos.org/IFF/IFF.html >> Perhaps fortunately, I am an engineer not a philosopher! >> >> Jeremy >> >> >> [1] Don Cupitt, 2001, Emptiness and Brightness, p95 >> >> >> >> >> > > -- > Rick > > cell: 703-201-9129 > web: http://www.rickmurphy.org > blog: http://phaneron.rickmurphy.org > >
Received on Sunday, 8 February 2009 22:58:35 UTC