UFO's seen growing on the Web
By bblfish on Apr 06, 2006
UFO's, or Unified Foundational Ontologies, have struck again on the Semantic Web mailing list last week. Apparently they do this quite regularly, but the pattern of the attacks is not quite clear. They arrive in groups it seems and attack with incredibly long posts making references to huge numbers of philosophical and logical arguments from well known and respected accademics. Clearly the typing fire power of these aliens is way superior to mine or any I have seen in real life. Furthermore their reading capacity must be astounding, as they will throw out book references and expect one to have read them before the reply is over. But they have a weakness which is, it seems, rooted in biology. On the surface though they make the following claims:
- There are some structures that RDF is missing that makes it impossible for it to express some/many very important UFO concepts.
- That previous experience has led to disaster (known as the AI winter), because they did not work with the right UFO
- There are no UFOs yet, so no work can be done
Now on point 1. it is quite clear that the Aliens don't have a very good
grasp of RDF as I see it. They are still amazed
that RDF is not about syntax. You can write RDF in a huge
number of different ways, to expressing
the exact same thing. The reason this is possible is because RDF is
built on the relation between names as URIs and the things they refer
to. This relation is also known as Semantics. Since the names used are
Universally unique (URIs), it does not matter much if your write your
sentences aRb or Rab or abR or ≤R sub="a" obj="b"≥ or however you
prefer. This emphasis on universally unique names is completely new. It
changes things fundamentally, and yet it seems so innocuous.
In any case it is very dubious that there are things that cannot be expressed in rdf (especially with the addition of graphs as found in SPARQL) but that could be expressed in other ways, as [check reference] it is at least as powerful as first order mathematical logic.
Finally there is some existential proof to the contrary with DOLCE, "Descriptive Ontology for Linguistic and Cognitive Engineering", for which there is an OWL version.
Now on point 2. the case has been made that there may never be one UFO design that is clearly better than the others, and even a lot of skepticism that UFOs exist or are even possible. Harry Halpin provided some extensive references to back up that claim, and neatly wrote this out in a very interesting article The Semantic Web: The Origins of Artificial Intelligence Redux. (Well from the lengths of Harry Halpin's posts I sometimes wonder if he is not one of the Aliens too). But of course one only needs to look at Guha's thesis Contexts: A Formalization and Some Applications (summarised in my previous post Keeping track of Context in Life and on the Web) to understand that creators of the Semantic Web were very aware and had a very clear understanding of the contextuality of information. Information may be inescapably contextual. But that is not a problem. Using Lifiting rules one can decontextualise information (to one's own preferred context of course).
So that leaves the fact that there are no successful UFOs around, and yet it would be nice to have some good ones to play with. If they were around and easy to understand then we would have a context in which we would know it to be easy to merge information. I imagine database administrators would be really happy with this. No need to Refactor Databases anymore. We could start with a clean database layout using our UFO, and be assured that data would always fit nicely into it. Well life is life. It's not always as easy as we would like it to be. Humans have always been able to communicate, and this must have been possible without UFOs, since we are here.
So in the end the best way is to do exactly what the SemWeb does. Build a very flexible system on some very basic principles: URIs, triples, http, add an optional inferencing layer and allow the web to create a distributed framework. Grow UFOs! don't design them. 
- An I'll throw in a reference of my own Ruth Garrett Millikan's Language, Thought, and Other Biological Categories: New Foundations for Realism where she shows the fundamental biological nature of language, and how natural selection comes into play in grounding words in reality.