Re: Web Rule Language - WRL vs SWRL

My reply to this thread is now in rdf-rules
  -JH

At 15:49 -0400 6/22/05, Michael Kifer wrote:
>Bijan Parsia wrote:
>>
>>  Perhaps this should move to rdf-rules?
>
>Perhaps.
>
>
>>  On Jun 22, 2005, at 11:29 AM, Michael Kifer wrote:
>>
>>  > Bijan Parsia wrote:
>>  [snip]
>>  >> To extend the conversation in another direction, is there any reason
>>  >> to think
>>  >> that a logic programming paradigm, in general, is the right approach
>>  >> to nonmon
>>  >> on the Web? Representationally? There are many non-monontonic
>>  >> formalisms
>>  >> (consider default logic and autoepistemic logic) and it might be that
>>  >> they 1) are
>>  >> better for web contexts and 2) play better with owl. (It's plausible,
>>  >> for example,
>>  >> to think that default logic can be made to fit better because of the
>>  >> separatation
>>  >> of the base representation and the default rules. Even there,
>>  >> adjustements must
>>  >> be made.)
>>  >>
>>  >> (Of course, anything in this space runs into the problem that, in
>>  >> general,
>>  >> nonmon formalism are much more computationally difficult than
>>  >> corresponding
>>  >> monotonic ones. The LP position often appeals to the
>>  >> scalablility/computational
>>  >> goodness of, say, deductive databases. But if that comes at the price
>>  >> of
>>  >> throttling back expressivity forever...maybe it's not such a great
>>  >> idea. Pat Hayes
>>  >> often, to my understand this, as thinking of nonmon constructs as
>>  >> part of the
>>  >> *data* on the web (to his mind, bad), and nonmon as a way of
>>  >> *reasoning with*
>>  >> the data on the web (good...it's located in the agent or processor
>>  >> which is in a
>>  >> position to make certain assumptions with a good sense of the risks)).
>>  >
>>  > These are all valid points for future research.
>>
>>  That's the extension of the conversation I'm after.
>
>
>I think it is a research program. I don't think much, if anything, can be
>accomplished on a mailing list.
>
>
>>  > I believe, however, that
>>  >
>>  > 1. It is naive to assume that one single formalism like DL or LP would
>>  >    serve the humankind forever.
>>
>>  I certainly don't think that.
>
>Good!
>
>
>>  >    The architecture should provide for multiple formalisms (where the
>>  >    formalism would be identified together with the statements -- RuleML
>>  >    attempts to do something like that).  The communicating parties will
>>  >    either be able to talk (if they both understand that particular
>>  > formalism)
>>  >    or they won't, but at least they will know it.
>>  >    Certain degree of interoperability between the different formalisms
>>  > can
>>  >    be provided without them being built on top of each other.
>>
>>  This is going in a different direction, which I'm sympathetic too. But
>>  it seems to end up in the land of multiagent systems (with agents
>>  wrapping and mediating different data sources). That *doesn't* seem
>>  like the semantic web as I've heard it articulated.
>>
>>  Maybe the semantic web as such is impossible!
>
>
>I don't know what "semantic web as such" is, but I do believe that
>defining it as a single stack is doomed to fail.
>
>
>>  > 2. Regarding the suitability of LP, this is backed by over 30 years of
>>  >    practice.
>>
>>  Hmm. Yes and no, right? The question is suitability *for what*. Of
>>  course, we're all groping in the dark, really.
>
>LP has been used for knowledge-intensive apps for as long as I stated.
>Webby things are not that different -- just another application.  There are
>interesting problems for sure, but it is funny to watch some of the
>discussions in which people create fetishes and pray to the god of URLs.
>
>>  The W3C made a bet
>>  though that is not easily reconcilable with LP (and components of
>>  which, at least, have similar depth in background). So, do we zig? Zag?
>>  Stay the course? Stay mostly the course? Start over?
>
>So, they erected one stack - this is fine. If they will insist that this is
>the one and only true stack, then the thing is going to die due to
>irrelevance.
>
>
>>  > Default logic is nice, but it is just a theoretical tool at
>>  >    this point. Before it (or its derivatives) can make into a Web
>>  > standard,
>>  >    I suggest to give it a try (or **practical** use) for, say, 10
>>  > years by a
>>  >    reasonably sized user community.
>>
>>  While that would be my general suggestion for *EVERYTHING* :), betting
>>  seems to be the name of the game.
>
>See, organizations like OASIS let their standards to die. If W3C is fine
>with that then they can bet all they want.
>But it seems to me that W3C is not prepared to kill its own standards, and
>in this case it should bet very carefully and with an eye on the future.
>
>>
>>  Looking at LP land, I don't see systems doing the "Web" thing. Of
>>  course, I'm not entirely sure what the web thing *is* really. I'd love
>>  to have better clarity on that so we could figure out what really
>>  *should* be going on.
>
>Exactly. What is the "Web" thing precisely?
>If you view it as a large distributed KB then LP is arguably doing this.
>
>
>>  However, and I think it's a reasonable position, you are actually
>>  advocated a non-integration strategy. (As you said in one.) That's
>>  fine, but then I would like it if those cards were laid on the table
>>  instead of claims of integration, overlap, compatibility (let me note
>>  that you are not the one making such claims). Let's change the freaking
>>  architecture to a hub and spoke, or whatever.
>
>As I said, it is presumptuous to claim that the current technology will
>remain true for all times -- even for 5 years from now.  A realistic
>architecture should allow for more spokes.
>
>>  Why two stacks instead of
>>  twenty and how do you make those twenty talk *at all*?
>
>One way for them to talk is to allow them to view each other as black boxes
>and send queries to each other. This is essentially the architecture of
>AL-Log. The Eiter et all. papers that you cite in your paper take the same
>approach and try to integrate DL with LP a bit tighter.
>
>It is strange that you even cite Eiter's paper because, if anything, this
>paper is an argument that a single stack is a bad idea and that several,
>loosely integrated, stacks is a way to go.
>
>
>>  This is close to the RuleML view of things. I've watched RuleML for
>>  quite a while and I still believe that its approach, while appeal, is
>>  not the kind of thing that the W3C likes to do. They like to pick
>>  winners, rather than pick integration formats. (Of course, they like
>>  picking winners at the "right" level...XML is pitched, after all, as an
>>  integration format!)
>
>Winners? How do they determine who the winner is? (The rest of the diatribe
>is not for a public list :-)
>
>
>	--michael

-- 
Professor James Hendler			  Director
Joint Institute for Knowledge Discovery	  	  301-405-2696
UMIACS, Univ of Maryland			  301-314-9734 (Fax)
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Received on Wednesday, 22 June 2005 22:05:41 UTC