RE: What do the ontologists want

>On Sat, 19 May 2001, pat hayes wrote:
>
> > >
> > >: pat hayes:
> > >:I am still trying to
> > >: find out what 'resource' means, but Dan Connolly tells me that:
> > >: the standard [definition of resource] is RFC2396:
> > >
> > >In RDF, a resource is something identified by a URI (that may have
> > >anchor ids) as per rfc2396. That's all there is to it.
> >
> > Oh. The trouble is, the reason I wanted to find out what resources
> > were was in part so that I could find out what URIs were. URLs I
> > understand - they are a kind of global file-name -  but the W3C folks
> > seem to think that URIs are something much more comprehensive than
> > URLs: they *seem* to be saying that anything in the universe that can
>
>"some W3C folks", please. There are a few of us, we all seem to be URI
>enthusiasts but ascribing a common technical view to the lot of us is a
>bit premature.

Sorry.

>
> > be referred to by any language can be indicated by a URI, so that if
> > I want to talk about the electron density of the Oort cloud, or a
> > grain of sand on Pensacola beach, well then I just use a URI.  (I
> > don't know quite HOW to do this, but I'm willing to learn.) So that
> > means that *anything* can be identifed by a URI, so *anything* is a
> > resource. People who died five centuries ago are resources, leptons
> > are resources, sets of integers are resources, Unicorns are
> > resources, Father Christmas is a resource.
>
>Yes

Good. So 'resource' is just a meaningless buzzword. We could 
transcribe it as 'entity' or 'thing'. I'm not complaining, just 
wanting to get that clear. It's something of a relief; now I can 
think of RDF as just being a 'description format', for example.

>....
>Yes, URIs are just names. Names in a certain syntax and with some controls
>over who gets to dish them out. URLs are too, though URLs tend to encode
>information about how to get at the named thingy using networked
>computers. URLs aren't simply file names:

Yes, I know. I said 'kind of', but should have said something like 
'globally addressable resource' or some such. Sorry, I meant only to 
indicate that the concept of a URL makes sense in a way that other 
URIs do not.

>they've long been used to name
>Web services (eg CGI scripts etc), internet mailboxes, format and language
>negotiated resouces and various other kinds of thing that aren't commonly
>considered 'files'. URI (and URL) syntax is specified in RFC2396.

URIs are names for anything. But their syntax is restricted. Suppose 
I am in the state of knowing that, say, something exists which is 
satisfies some complicated description, and I want to use the logical 
rule of existential elimination to give this thing (that I know 
exists) a logical identifier, ie a name. To whom must I apply for 
permission to use a suitable URI?

>URIs, sadly, aren't magic at all. Just useful. URIs are handy
>(particularly in electronic publishing, web services etc) since we've an
>agreed convention for devolving names to organisations and individuals
>for use. Their use makes it easier to do database joins, at least for
>descriptions of things that have widely agreed URI names (like Web pages,
>mailboxes etc). This in turn makes it a little bit easier to talk about
>things that don't have widely understood Web names, eg. we can talk about
>you in DAML+OIL through using various URIs (phone number, home page,
>mailbox) to pick you out. The common URI syntax just reduces the number of
>different ways of writing down your phone number etc, making it a bit
>easier for databases to join up scattered descriptions of you.

This is an aside, but I fail to see how it does that. My phone number 
might occur on many different web pages in various different formats, 
and some of them might have an out-of-date number that is no longer 
my phone number. (In fact, all this is true.)

> > >I find it's
> > >useful way to think when it comes to implementing code.  That may
> > >seem a backways determination; if I create a URI do I create a
> > >resource for it to identify? This is moot, the RDF machine can't
> > >access a resource directly anyway, but it allows for the description
> > >of say, unicorns.
> >
> > It does? How?
>
>(process point: if we're going to have a discussion about identification
>and description of non-existent or hypothetical entities, please start a
>new thread.)

Will do.

Pat

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Received on Saturday, 19 May 2001 22:41:09 UTC