RE: Rich semantics and expressiveness

 
It is ironic that the word "semantic" seems to have become meaningless... 
 
Traditionally, semantics could be
 
a).  a consensus about the way language can be used - the valid operations. (operational) 
b).  a mapping to a "real world" (denotational)
c).  a collection of logical deduction rules (axiomatic). 
 
What are the ambitions of the semantic web? Is it a controlled language for a restricted domain, or is it more ambitious? Is it a logical formalism, or does it refer to something "out there"? If our ambition is universal interoperability it seems to me (  ;¬P) ) that a). is hopeless - language is finite but concepts are infinite and the world in is constant flux. And c).  is uninteresting - if there was universal agreement about a simple set of rules, there would be no debate. So for me me question is, how do we reach a consensus on how to use ontologies in practice? Again it seems to me that within restricted domains it might be possible to agree on a common ontology and the way it should be used - but on a global scale, language is defined by consensus, and is characterised by ambiguity and even disagreement at the margin. So different computer systems may come up with different answers that each considers correct - this is true of human languages. 
 
Sorry if this is old hat, but I am not sure that the SW community even agree what "semantic" means. 
 
Tim.  
 
 
 

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From: semantic-web-request@w3.org [mailto:semantic-web-request@w3.org] On Behalf Of Hans Teijgeler
Sent: 03 March 2007 10:19
To: SW-forum
Cc: West, Matthew
Subject: RE: Rich semantics and expressiveness


Folks,
 
In this context I would like to bring up something that keeps puzzling me.
 
The W3C Semantic Web Activity Statement [1] starts with:
 
"The goal of the Semantic Web initiative is as broad as that of the Web: to create a universal medium for the exchange of data. It is envisaged to smoothly interconnect personal information management, enterprise application integration, and the global sharing of commercial, scientific and cultural data. Facilities to put machine-understandable data on the Web are quickly becoming a high priority for many organizations, individuals and communities."
 
This is great, and it is what we strive for. But it is puzzling how this can ever be achieved without a universal, generic, data-driven model and standard data to drive that model. What I see happening is that everybody can and often does invent instances of owl:Class and owl:ObjectProperty on-the-fly, and then seems to expect that DL will be the band-aid that solves all integration problems. In order to assist the reasoners all sorts of qualifications are added (re OWL1.1), but to me it seems that when this is done, actually a (rather private) data model is created again.
 
Above statement envisages the "smooth interconnection" of a plethora of totally different application domains. That is wise, because we live in one integrated universe (domain), and nobody can dictate where one subdomain stops and the other begins. Hence the need for a universal model as a common denominator. But it is striking that the word "interconnection" was used, rather than "integration". Interconnection reminds me of EAI [2], so hub-based or point-to-point, where Semantic Web integration (as I understand it) involves a web-based distributed data base.
 
Keeping in mind that, as I wrote before in this thread, application systems store a lot of implicit data (or actually don't store them), the direct mapping of their data to the SW formats will cause more problems than its solves. They are based on their own proprietary data model, and these are unintelligible for other, equally proprietary, data models.
 
The thing puzzling me is how the SW community can see what I cannot see, and that is how on earth you can achieve what your Activity Statement says, without such a standard generic data model and derived standard reference data (taxonomy and ontology). But perhaps not many SW-ers bother about the need of universal integration, and are happily operating within their own subdomain, such as FOAF.
 
Can anybody enlighten me, at least by pointing to some useful links?
 
Regards,
Hans
 
PS The above does not mean that I have no faith in the SW. On the contrary, I preach the SW gospel. But I just want to understand where it is moving to.
 
[1] http://www.w3.org/2001/sw/Activity
[2] http://en.wikipedia.org/wiki/Enterprise_Application_Integration
 
____________________
OntoConsult
Hans Teijgeler
ISO 15926 specialist
Netherlands
+31-72-509 2005
www.InfowebML.ws <http://www.infowebml.ws/>  
hans.teijgeler@quicknet.nl
 
 


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