Re: comparing XML and RDF data models

On 3 Jul 2008, at 00:27, Peter Ansell wrote:

> 2008/7/3 Bijan Parsia <bparsia@cs.man.ac.uk>:
[snip]
>> I think you radically underestimate this. Talking with biologists and
>> bioinformatics people reveals otherwise.
>
> It depends on which level you are trying to determine uniqueness.

Once you've acknowledged this, then, I believe dialectically  
speaking, game over.

At the very least, it means that starting with "In my view the key  
point is that with RDF we have unique identifiers
for concepts" without a *lot* of explication and, in particular,  
exact analysis of whether XML has it (or equivalent) is required.

> Ie,
> whether things have to be the same thing with all the same properties
> and functionality and context, or whether you classify them as being
> the same if they are different things with a shared property or
> functionality.

I don't know what this means.

>> It's also basic logico-mathematical fact. We can't get unique and
>> unambiguous names for *integers*.
>
> Why are we naming integers?

I was trying to point out that even with such well described and  
behaved entities as integers, we can't get unique and unambiguous  
names. See, Benacerraf's article "What numbers cannot be"

[snip]

>> I don't know what a universal thing.
>
> Sorry, I thought that would be obvious.

I'm really curious as to why you think it would be obvious.  
"Universal thing" is not a common phrase and it usually doesn't refer  
to particulars (for example). Its's not a standard term of art (that  
I know of).

> In my realist view there are
> things that people are trying to describe using RDF and those things
> have identities, which we are labelling with names, or describing
> through identifying properties.

The charitable thing for me to say here is that you have a complex  
background view. This brief description, to the degree I can make  
sense of it, isn't going to help all that much on the current issue  
(if I may be so bold). It bears some resemblance to Tim's attempt to  
appeal to a univocal (or inherent) data model. I suggest you read our  
exhange to get a feel for some of the issues that arise.

(Note that by many readings "having identity" is literally nonsense  
(e.g., if we are thinking about identity *relations*. In other  
readings, things are more complicated, after all, I talk about my  
identity as a academic or as a person; my "identity" can survive my  
losing a foot but not my brain, etc.)

> These are universal things.

To the degree I can make sense of this, I have to say that the term  
"universal thing" is an exceeding bad one as these seem to be  
*particulars*, not universals.

It's hard to understand how this relates to concepts (which is what  
Mark was talking about.)

I would find it helpful if you either established a completely  
different discussion, or tried to stick a bit closer to what Mark  
said (if you are going to defend it).

> If you
> want to establish equality you are likely to be doing it at this
> level, unless you assume that markup is everything and a thing is only
> in existence because there is a description of it, and the description
> of the thing causes the thing to exist.

This all just seems radically false. As well as confused.

First, I don't know what it *is* to work "at this level". Even if  
there *are* such things, it's very unclear how we have access to  
them. To wit, what that level is. (To pick a simple example, why do  
you presume that the world is made up of *entities* rather than  
*processes*? This is a fundamental choice in ontology.)

[snip]
>> Please see:
>>
>>  <http://www.w3.org/mid/44444506-BC65-4BB9- 
>> AF6B-01FE434C6C3A@cs.man.ac.uk>
>
> Not sure how that helps... I am saying pretty much the same thing I  
> thought.

I mean to appeal to the last paragraph.

[snip]
>> Again, I urge semanticwebbians to be *ruthless* in our scrutiny of  
>> the sorts
>> of claims we make.  We have a *bad* reputation for Koolaidoisity,  
>> and, I'm
>> afraid, it's well deserved. We're not going to win over  
>> unconvinced people
>> by grandiose and vague magical claims.
>
> I don't make any of those claims. Acknowledging that two names aren't
> going to be unique, why explicitly being able to say that two names
> refer to the same thing isn't grandiose, its quite pragmatic.

I'm confused. Mark make a claim that RDF had unique names for  
concepts (and XML doesn't). I critiqued it, and, afaict, you defended  
it.

But now you say you aren't defending it. I'm confused.

>> ...or maybe we will. Plenty of stuff works that way. But I don't  
>> like it.
>> I'd rather say true and extremely intelligible things.
>
> I am not sure what you mean by extremely intelligible.

You appeal to a lot of idiosyncratic background beliefs and terms.  
You aren't giving concrete examples. Not having the former and having  
the latter makes things more intelligible to me. YMMV.

> Settling for
> the basics, at least initially, is a good thing. Some people will use
> RDF just for documenting things without having to first write up a
> schema, others will use it because they have complex models and rules
> that they want to represent.

This fails to distinguish it from XML.

> Both should be allowable within semantic
> applications, and constant debate over whether a particular string
> should be universally unique as a way of talking about a particular
> universal thing doesn't help that goal at all.
[snip]

I agree with that! Strongly.

Cheers,
Bijan.

Received on Thursday, 3 July 2008 13:28:31 UTC