On 24 Mar 2009, at 15:17, eric neumann wrote:
Bijan,
I have a (possibly) naive question, but one that comes up in the
context of a digital record/rep of the protein :
Are OWL ontologies supposed to be applied to only digital
representations of real world things,
No. Indeed, that's toward the "working against OWL" end of the
spectrum..
or do some believe they actually can be applied to the real-world
things "even when no record of the object exists in the digital
space"?
That's the more common understanding. OWL ontologies are interpreted
into mathematical structures (e.g., sets and sets of pairs and
elements of those sets) which, ideally, should be isomorphic to the
domain you are trying to model.
That is, among the models of your ontology, it would be nice if one
of the models interpreted Individuals as individual(ish) things in
your domain. So, in an ontology about Persons, "bijan" should be
mappable into me (or to a corresponding element in an isomorphic
structure).
In the world there are digital things (like programs, records, etc.)
which can be (sometimes) modeled as individuals. I can model these
side by side with the physical objects those digital object represent
(or are created by). This is the case when I'm doing entity
reconcilation, for example, since the person and the 2 records about
her are numerically distinct (i.e., all differentFrom each other).
Other times, I don't make the distinction because, for my purposes,
the record is a sufficient proxy for the entity and keeping them
distinct would complicate things too horribly.
[snip]
In addition, I also don't see references to any object being
fundamentally different to a digital record (san descriptive
triples perhaps)... can someone provide me with a counter example?
An ontology is, of course, itself (in our case) a computational
artifact. And if we don't add enough assertions to distinguish
between a representation and an object represented, then we can't
distinguish them using our ontology.
Methodologically, it's sometimes helpful to view ontology
construction as the process of removing unintended models. Each
additional axiom (hopefully) distinguishes enough features of the set
of interpretations that a few more interpretations become non-models.
In the ideal limit, we have all and only intended models as models of
our ontology. That's what's known as a *verified* ontology.
Furthermore, it'd be nice if our intended models were isomophic to
"the world" (under some conceptualization).
Often the ideal limit isn't reasonable or feasible or helpful.
Frictionless pullys are pedagogically useful, after all.
These slides contain some discussion of this:
http://www.cs.man.ac.uk/~bparsia/2009/comp60462/semantics-and-services/
Hope it helps.
Cheers,
Bijan.
