Re: SEMIS Bulletin
Pat,
The last thing I want to do is to attack the people at
the W3C, many of whom are outstanding computer scientists
who have been doing some excellent work, much of which I
use every day and about which my biggest disappointment is
that the majority of computer users still use browsers that
do not meet their recommendations.
Before responding to your comments, let me repeat the summary
of what I do recommend:
JS> In summary, my recommendation is to replace the term
> "semantic web" with "semantic system" and to integrate all
> related technologies -- including SQL, UML, EXPRESS, OWL,
> RDF, and others -- on a common logic-based foundation.
> The human interface should be controlled NLs supplemented
> with graphics. XML could be used as an exchange format for
> anybody who wants to use it, but more flexible formats
> should also be permitted (for anybody who wants to use them).
I apologize for using the word "semantics" in a very loose way:
JS> ... that are far more "semantic" than anything that is
> being proposed for the semantic web.
PH> ? What does THAT mean?
I just wanted to say that the EXPRESS group has been doing
important work on aspects of semantic modeling that the
semantic web group has not yet begun to take into account.
Instead of focusing on a foundation of XML + URIs, I believe
they should have started by asking what they could do to build
on and integrate already successful projects in related areas.
PH> The SW isn't focused on 'electronic product information',
> for example. And this doesn't mention the Web at all, whereas
> the Sweb has always been seen as a step in WWW evolution.
The third line of that comment is what bothers me: I view the
WWW as a simple, but hugely successful way of taking advantage
of a 40-year-old infrastructure. HTML + http + URLs are just
a tiny tail on a vastly bigger elephant. The Sweb is focusing
on evolving the tail while ignoring the elephant.
The STEP group focused on the much bigger problem of using the
entire infrastructure (including the web) in order to put semantic
modeling at the center of every aspect of the business process,
including hardware and software design, development, manufacturing,
distribution, and communication with clients and suppliers. I'll
admit that there's more to the elephant, but STEP started with
the brain and included a much bigger chunk than just the tail.
PH> Are there any STEP reasoning engines?
Unfortunately, the STEP group, on average, is no better grounded
in logic than the W3C. The fact that EXPRESS happens to have
the expressive power of FOL is due to luck: If you want to
translate natural language spec's into any declarative notation,
it will inevitably include the full power of FOL.
Re reasoning engines: I'm not familiar with all the things that
are going on in the STEP community, but I know a few people who
do have good logic backgrounds. Perhaps they have done something,
but in any case, I agree that more work is needed on that part
of the elephant.
PH> But it is critical that the Sweb is not just another industrial
> interchange standard. It needs to be truly universal and to be
> integrated into the existing WWW technology. This isn't easy or
> trivial: sometimes its bloody awkward.
I agree with the "bloody awkward" part. But they brought that on
themselves. If you start your architecture project by insisting
on Lego blocks, you can't interface with Tinker-Toy pieces.
PH> OMG has an effort in place to map XMI and MOF with OWL and SCL,
> for example. The RDF group spent a *lot* of effort ensuring that
> RDF would be properly integrated with XML-Schema datatyping. And
> so on. Still, it would be a mistake to think of the SW as primarily
> a way to integrate existing standards: its much more than that. By
> its global nature, it has the promise to make semantic integration
> a non-problem, for example.
That is more Tinker-Toy and Lego-block semantics. It's more likely
to make semantic integration a nightmare than a "non-problem".
PH> ... I have my own complaints about aspects of the URI design
> (and particularly the rather peculiar semantic theories which
> seem to lie behind it) ... but I have to say, the URI design is
> about as good as it gets; its the only real attempt at a global
> identification scheme yet deployed by any organization; and it
> is closely related to a rather impressive technology suite, viz.
> the WWWeb infrastructure itself. BTW, all of the examples you
> cite can be encoded within URIs and in every case there is
> deployed technology which makes use of such an encoding.
I believe that it's a mistake to associate any kind of semantics
with names of any kind. I also believe it's a mistake to make the
naming scheme "closely related" to any kind of "technology suite".
The original URLs were based on the Unix file system -- trees with
cross links -- tied together with the Internet naming scheme as
the top-level tree that ties together all the little trees. All the
other naming schemes are either trees with cross links, simple trees,
or flat lists (which are very simple trees). Any of them can be put
into a universal scheme by attaching them at some node of the upper-
level tree. The things that the names point to have the semantics;
the names themselves should just be globally resolvable pointers.
PH> ... Part of the reason is precisely the 'simpler links' that you
> mention so casually (which are certainly not used in simple ways,
> eg check out what Google does with them). The WWW isnt just
> another network; if it were, it would just be the Internet: so
> it evidently is more than just that.
That's what I said. The original WWW got an enormous amount
of power by adding a tiny increment to the elephant. I'm not
complaining about that. What I reject is the idea that they
can be successful in semantics by adding more decorations
to the tiny increment while ignoring the elephant.
PH> ... All of the W3C efforts are designs by committee (do you
> think that the ISO is going to be any different??) so one should
> not think that because something is finally rejected that it has
> been ignored. There are still some energetic LISPers working
> on the SWeb as a kind of underground army, in any case.
The original WWW was great because the basic structure was
designed, implemented, and widely used *before* the committees
got hold of it. Then the committees did some good work in
filling the holes, smoothing the rough edges, and adding
decorations. Committees are terrible at design, but very
good at criticism.
The weakness of the semantic web is that the committee took
charge from the beginning. The people who formed those
committees would have done much better if they had gone off
in small groups, implemented some competing projects, and
then got together to compare them.
PH> ... I agree with the common logic-based foundation, as of
> course do many in the SWeb community. Its much harder to obtain
> agreement on a *particular* logic-based foundation, however.
> For example, one highly influential and vocal contingent insists
> that any viable Web logic must be decideable. Others insist that
> it must be nonmonotonic.
That's committee talk. I make note of their points and go off
to design my own, very general framework, which includes all
of them as subsets. I don't claim to be omniscient, and I
recognize the need for help, suggestions, and criticism at
various stages. And I would be very happy to see other
people work on similar kinds of designs. Then we can meet
periodically and borrow ideas from one another. I don't
know the outcome: perhaps we'll all converge; maybe we'll
end up with a few competing designs; or we might all give up.
John