Identifying Ontologies with URIs

As noted before in my original ephiphanies #10 & #15 and Level III Existential Programming, there should be a whole collection of meta-data around each "fact" documenting the source of that data, the time that data was acquired, etc, etc. This meta-data in effect constitutes an ontology definition; one per each different source/timestamp/etc. To be sure, these various ontologies are largely similar to each other and could benefit from an inheritance tree (ala OO class hierarchies).

In Java, such collections of definitions can be grouped into Packages. In XML, they can be grouped into Namespaces. So, a pragmatic way to factor out this metadata (such that it is not copied into every "fact"), is to give the ontology a name and tag each fact with that name (in the same way as each Java value is "tagged" with a data type that includes the Package name/path). And since, XML has already defined URIs as the format for namespace identifiers, and it is easy to map Package names with URIs, Existential Programming systems/languages could use URIs to identify the ontology associated with some set of facts. Since Existential Programming systems seek to seamlessly convert between an O/O and an E/R and an S/N representation, having OO packages easily mappable to data exchange mechanisms like XML is a good thing.

POSTSCRIPT - Nov 23rd, 2007
It is hard to tell which of my epiphanies are new and which are things I read long ago but later remembered as if they were a new idea...I'm sure I read this URI stuff in the Semantic Web articles (see Principle #1), but only "remembered" it when stumbling back across it today. At any rate, it was only recently that Tim Berners-Lee wrote this post about Linked Data using URIs.