Re: philosophical question about occurrences

Dunker,

Please consider publishing your thesis on the Web somewhere and notifying 
this list.

Thanks
Jack

At 03:10 AM 2/20/2003, Murray Altheim wrote:
> Dunker wrote:
> > Hi everyone,
> > I'm in the process of writing my MA-thesis, which has a good deal to do
> > with topic maps. In one chapter I present the paradigm's major
> > concepts. While writing about occurrences, something struck me: the
> > literature usually says that occurrences ARE the resources that topics
> > refer to. So, I thought, resources are called (or turned into)
> > occurrences once they are referenced by a topic. Steve Pepper indicates
> > this in his TAO-Article: "A topic may be linked to one or more
> > information resources that are deemed to be relevant to the topic
> > insome way. Such resources are called occurrences of the topic.". The
> > same is indicated by the XTM-specification: "An occurrence is any
> > information that is specified as being relevant to a given subject."
> > However, occurrences can be scoped. The same resource  - let's say a
> > fictional piece of text - could be occurrence for two or more topics -
> > let's say two characters appearing in it. Character Paul is the main
> > character in the story, while Peter is a side character. I could scope
> > the occurrence with "main character" for topic 'Paul' and with "side
> > character" for topic 'Peter' (The example might not be a good one, but
> > technically this is possible). But, what I have actually done, is
> > scoping the _reference_ to the resource, not the resource itself. Which
> > scope I choose is dependent on the topic the resource is referred from.
> > So, if we say we can scope occurrences, are occurrences really the
> > resources themselves, or are they references to the resources? The same
> > problem appears in connection with occurrence types: If I type an
> > occurrence as 'mention', I really type its reference. Holger Rath
> > indicates this in an article(1) from 2001: "An occurrence is the link
> > to an information [...] - it connects the topic domain with the
> > resource domain."
>
> Essentially, an occurrence is considered a *characteristic* of a
> topic, i.e., that is its relation to the topic. This relation is
> governed by *scope*, or the context in which this relation is true
> or relevant. The semantics of this are straightforward, so long as
> you keep in mind we are talking here about an abstract model of
> topic maps and not any implementation.
>
> I believe your difficulty is not in these semantics but in mixing
> levels of interpretation. In terms of the semantics of the relation
> between a topic and its occurrences, you can effectively ignore issues
> of resources and references, i.e., what occurrences are, how they're
> connected (mechanisms of reference), how many layers of reference
> are used to make that connection, etc. -- these operate at lower levels
> than the abstract model, something we might call an "implementation"
> level.
>
> In the "topic map graph" -- the abstract structure of the topic
> map -- the arc connecting a topic node to an occurrence node
> ignores the behind-the-scenes implementation; it's simply seen as
> a connection. You could implement a topic map using strings and
> rocks, or with a pencil and paper. This kind of thing has been
> done publicly with ribbons, tape, and human bodies. You aren't
> scoping the reference, you're scoping the occurrence -- the
> reference is simply the mechanism by which the occurrence is
> "physically" (implementationally) connected.
>
> If you think about it, everything we use to communicate topics
> (and more generally, everything we use to communicate, full stop),
> from our use of spoken language, the glyphs of its representation
> in written language, the use of XML syntax in representing topic
> maps, all are simply references -- in semiotics they're considered
> "signs". I don't mean to sound philosophical, it's just that once
> one begins to decompose modes of reference, it's a spiral right
> down to the lowest possible decomposition, and I'm not sure there's
> any point in bringing that into your thesis unless you intend to
> discuss the semiotics of topic maps, i.e., how topic maps
> distinguish and map "subjects" (which is what TM topics actually
> reference), and what this means, which is an interesting topic in
> itself, but likely a different thesis.
>
> Murray
>
> ......................................................................
> Murray Altheim                  <http://kmi.open.ac.uk/people/murray/>
> Knowledge Media Institute
> The Open University, Milton Keynes, Bucks, MK7 6AA, UK
>
>     "In Las Vegas Mr Gates also demonstrated a prototype
>      fridge magnet which can be programmed to receive traffic
>      reports, sports results and advertisements from local
>      restaurants using the same FM signal as the wristwatch."
>                                  -- The Guardian, 10 Jan 2003.
>
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