Social networks status update

For those who care, and since I've mentioned a couple of them in the past two years, here is without comments on the why's and how's, the status of my current, past and potential online accounts on various platforms.

• Alive and updated on a more or less regular basis : Faviki, LinkedIn
• Alive but mostly dormant : Wikipedia, WiserEarth
• Used and rejected as noxious : Dmoz (10 years ago), Twine (last year), Twitter (today)
  
• Tested and forgotten : StumbleUpon
• Never joined, and no intention to do so : Facebook
• Unknown, and no intention to know more : all the rest, basically
  

If you stumble on something I forgot on-line, please drop a comment.
If you want to push me (back) to (re)-join X or Y, well, no, thanks.

Asserting subclasses of open ranges or domains

I had an interesting exchange on Semantic Web list on this issue last week. You can browse the whole thread, but I would recommend answers by Pat Hayes and John Sowa.
Below are extracts of my final answer.

1. There is quite a difference to make between concepts in ontologies strongly defined by domain experts, and targeted at feeding reasoners (e.g., bio-medical or legal ontologies), and lightweight ontologies such as FOAF, VCard, Dublin Core, Geonames ... which are mainly targeting interoperability of data, and of which meaning (if not formal semantics) emerge from usage and population. I can't define formally what a Person is, but I can say that you and I are some instances.

2. For the latter said ontologies, the main objective is to provide guidelines for applications harvesting and managing data. The actual formal semantics of those models is next to nothing, but implementations can reasonably leverage them on the basis of a common sense interpretation. For example the thousands of different data models to represent a person can be re-engineered as so many specifications of the generic class foaf:Person, therefore allowing a shallow, but efficient level of data interoperability.

3. There is no more, no less semantics nor potential usability in declaring skos:Concept to be in the range of dcterms:subject, than to declare foaf:Person to be a subclass of foaf:Agent. "Dont acte"

For some other ill-defined property ranges in the Semantic Web popular ontologies, another path would be to use enumerated classes, or in a more flexible way, to indicate a published vocabulary maintaining a reference enumeration. For example when LoC publishes later this year the authoritative ISO 639-2 list of languages as a SKOS Concept Scheme, the range of dcterms:language could be restricted to the values in such a list (using e.g., a restriction on the value of skos:inScheme). This would avoid Dublin Core to go through the painful task of defining formally the class dcterms:Linguistic System which is the current specified range - with the same lack of definition as foaf:Agent. Referring to some authority is certainly the best way to deal with the issue here. We (DC) don't know what a language is, go ask ISO 639-2 folks, apparently they know because they are able to provide a list.

From meaningless to ambiguous

A previous post looked at concepts as names species. Several threads about URI meaning and ambiguity later, including on www-tag@w3.org list this post from Karl Dubost, and with in mind again names and concepts as living things, here is yet another variation on morning, noon, and evening mountains.

Morning names, meaningless, useless
Names at noon, meaningful, useful
Evening names, abused, ambiguous

This basically is the life cycle of names from no use to use and eventually abuse. Use leads to meaning, then abuse leads to meaning overloading. This is the natural course of things. And since URIs are names, this is also the natural URI life cycle. So let us use what is meaningful while it is if we want meaning. Be prepared to ambiguity at the end of the day, but if evening ambiguous names have been abused, it does not mean they are useless.

URI species

The debate about proliferation of URIs representing the same thing keeps on rolling on various Semantic Web lists, going back again and again to the same questions. How does one discover existing URIs for a thing, if any? Is it a good or bad practice to mint a new URI for a thing which already has one? How do one link URIs identifying the same thing? Many smart and conflicting answers have been given, largely depending on the viewpoint on Web architecture and the main use of URIs in the mind of their authors. Web pragmatists and linked data evangelists tend to consider that proliferation of URIs is not necessarily a good idea, but something we are bound to live with, whereas experts in knowledge representation tend to consider it should be avoided by all means. Trust, persistence, quality of resource descriptions, use and abuse of owl:sameAs have been discussed over and over, with no obvious technical answer.

Since life provides the oldest, proven, efficient ways to store, maintain, replicate and use information, I've tried to figure if we could not learn from biology. Interestingly enough, biologists are not more able to come to a consensus about what a species is than Semantic Web gurus to agree on what is behind a URI. Somehow, the two issues are very similar. They deal with persistence of information over time. With the disclaimer that I am not a biologist, let me assume here the definition of a species as the set of individual expressions of some common genetic pool. Protection and persistence of the species genetic pool is the main occupation of any form of life. Strategies to achieve this goal present an awesome diversity, but in this variety one can find some constants. Among those are the basic facts that individuals are bound to a short life span, so the protection of the genetic pool is best achieved by assuming mortality of individuals, and ensuring duplication and replication of the information in as many individuals as possible. Not by defending a single representation behind firewalls.

How does that apply to the Semantic Web? A URI, along with the resource description it provides, can be seen as an individual expression of a species concept. As any human artefact, or any living individual, or any physical manifestation in this world, this expression is bound to be a transient. The agent who created and maintain the URI is bound to disappear, among other things. It will be less costly, as life tells us, to have copies of the information in as many expressions as possible all over the place, than to protect this specific one. Consider a URI not as the unique representation of a thing, but as an individual expression of a species.

Common Tag

Based on Common Tag specification and various APIs around, there are certainly a lot of easy next steps towards interfacing more efficiently the free tagging and linked data universe. For example it should not be too difficult to build an interface allowing the mapping of Twitter hashtags to DBpedia URIs, based on both Twitter and Zemanta APIs. Faviki could open this path.

Everything is a thing, everyone is many

So I'm now on Twitter, following a couple a people, hoping some interesting bits and pieces will float around to my shore. And well, some have. For example this interesting piece on Multiple Personas. What Silona writes there on the essential multiplicity of a person can certainly also apply to things and representations. We know more or less from inside our multiplicity and ambiguity, and the importance of keeping multiple personas revolve around our fundamental and essential emptiness. But we've lost most of the time the capacity to look at things the same way. As Jean Rousselot put it, we are not simple enough any more to "enter things as things can enter things"

Il faudrait pouvoir entrer sans frémir
Dans les choses
Comme les choses
Entrent dans les choses.

The poets are the ones able to enter things, experience their mutiplicity, and show how they appear to us as multiple personas.
We should look at the necessary convergence of the social and semantic web(s) with this paradigm of multiple personas in mind.

sameas.org

sameas.org is quite an implementation of hubjects for the linked data universe. It relies still a bit too much on owl:sameAs, but I begin to believe that owl:sameAs eventual semantics will be the one applications make of it. Only reasoners in closed universes will apply owl:sameAs for what it is in the standard (strict identity). Open Web and linked data cloud will use it as "follow-your-nose" hubs to switch from one representation to another and aggregate information.