Thinking Clearly .

One strange turn the Semantic Web Rules saga took is the elevation of Interchange as the point and purpose of the working group. If you go back to the prior round of discussion (which, in fact, resulted in a charter around the same time that the Data Access Working Group was being born) you won’t see “interchange”:

The group is chartered to develop a practical and useful rules language for the Semantic Web, along with a corresponding language for expressing justifications….

...This work is based the Resource Description Framework (RDF) in order to enable full interoperation with other elements of the Semantic Web, including the OWL Web Ontology Language and possible future languages for logic and knowledge representaion….

...The architectural vision for the semantic web has included an interoperable standard langauge for rules for a long time. The readiness and urgency in this field are growing, and have crossed the threshhold for Working Group creation….

Well, turned out not to be all that urgent, since it could wait for two years for any sort of group and the one we got was explicitly not chartered to do a Semantic Web Rules language!

(An aside: When interviewing for a lectureship at the University of Manchester, I was asked what one of my greatest frustrations was with my work. After a false start I said “Hype”. I’m really sick of hype. I remember being stung by hype back with the release of HyperCard. It’s wretched. I find it especially frustrating when I am seduced by the hypemonster myself. I think that negative hype is pretty obnoxious too.)

So, if the RIFraff are not doing a Semantic Web Rules language, what are we doing? What the heck is an Interchange Format and how does it differ from a rules language or a Web Rules language or a Semantic Web Rules language?

At the F2F we all agreed, properly, that whatever we produce will certainly be a language with a clear and well defined semantics. It’s the sine qua non of interoperability, hence of interchange. And we are chartered to produce a language compatible with RDF and OWL (in fact, one delieverable is a Rec track document describing OWL compatibility). So, what’s left?

To my mind, the main difference is in the desiderata and the design choices they impose. To hook in the rules/business rules vendors, the W3C has been trying to sell this as a language for exchanging rulesets between their systems. Whatever we produce has to be able to more or less do that. So, instead of starting from the thought, “What would we like a Semantic Web Rules language to look like?” we start with “What features must be supported by RIF in order to take rules from ILog’s thing to Jess?” Note that “webbification” is not, on this model, an inherent requirement. We’ll have it, but it’s not essential. Computational niceness is not an inherent requirement. Neither is stand alone useability. There’s a sense in which we are not supposed to pick and choose features…just to allow for two systems that support some set of features to be able to load common rulesets. (“Just” indeed!)

Given that we are explicitly working with a two-phase, core + extensions design, things are going to get complicated. Furthermore, there is the possibility of multiple semantics/semantic paradigms (e.g., as discussed in the OWL/RDF breakout session, we might specify that in this document implication is interpreted in minimal models or all models. More generally, it’s not clear that it will be easy or even possible (reasonably speaking) to provide a model theoretic/denotation semantics for lots of features/feature combination (leading to proposals to use formal operational semantics a la XQuery).

Illegal domestic spying, while itself not as bad as torture and extra-judicial indefinite detainment (among many other things), is still pretty amazingly awful. The exercise, even the petty exercise, of power without restraint should be completely unacceptable in our political culture. It is the antithesis of our democracy.

(Note, I will be including these little points at the bottom of all my posts because I can’t bear not to. I don’t have the energy to do the kind of political blogging I used to do at Monkeyfist, but I just feel sleazy posting nothing but on technical matters. I am thinking about this other stuff as I write these posts.)

This entry was posted on Monday, December 19th, 2005 at 10:58 pm and is filed under RIFWG, Rules. You can follow any responses to this entry through the RSS 2.0 feed. You can skip to the end and leave a response. Pinging is currently not allowed.