Re: Explaining the benefits of http-range14 (was Re: [HTTP-range-14] Hyperthing: Semantic Web URI Validator (303, 301, 302, 307 and hash URIs) )

Dave and all, hello.

I've been rather daunted from joining in to this braid, but I have responses to a number of Dave's points which I think pick up earlier observations, so please forgive the slightly patchy content below, and the vigourously trimmed quoted material.

On 2011 Oct 20, at 10:34, Dave Reynolds wrote:

> Hi Leigh,
> 
> On Wed, 2011-10-19 at 17:59 +0100, Leigh Dodds wrote:
> 
>> So, can we turn things on their head a little. Instead of starting out
>> from a position that we *must* have two different resources, can we
>> instead highlight to people the *benefits* of having different
>> identifiers? 

> Nice approach. Here's an attempt ...
> 
> Benefit 1: You can provide (meta)data separately about the IR and NIR
> [...]
> Counter argument: this is problematic anyway. If your IR can conneg to
> both an HTML and an RDF representation then by webarch they should be
> equivalent.

Where is this written (I can't find support for this in a quick search through <http://www.w3.org/TR/webarch/>?  I know that earlier in this braid Hugh Glaser remarked that the NON-equivalence of connegged representations was the elephant in the room, but it's never occurred to me that these would be _equivalent_ in other than a formal logical sense.  Surely conneg produces _alternatives_: a picture of the rain in Oaxaca is clearly inequivalent to RDF quoting the temperature, but they're both reasonable alternatives (not equally useful in all contexts, but this is the web -- you get what you're given).

In other words, is discussion of equivalences a red herring in the IR/NIR argument?

Ugh: 'IR' and 'NIR' are ugly obscurantist terms (though reasonable in their original context).  Wouldn't 'Bytes' and 'Thing', respectively, be better (says he, plaintively)?

> Benefit 2: Conceptual cleanliness and hedging your bets
> 
> [...]Even if we can't spot the practical problems right now
> then differentiating between the galaxy itself and some piece of data
> about the galaxy could turn out to be important in practice.

It is.  I want to say that 'line 123 in this catalogue [an existing RDBMS] and line 456 in that one both refer to the same galaxy, but they give different values for its surface brightness'.  There's no way I can articulate that unless I'm explicitly clear about the difference between a billion suns and a database row.

This seems such a knock-down argument, that I have difficulty seeing how anyone gets up again afterwards.  The only counter-counter-argument I can imagine is "yes, Norman, but not everyone is a scrupulous as you about the distinction, and sometimes people produce URIs which blur it", to which the response is "sure they do, and life as a consumer of wild-wild-web data is cruel and heuristic, but that's a completely separate issue: it doesn't mean that you can't get this right _as a data producer_".

> Cost 1: You have to decide if your resource is an IR or NIR and we can't
> always
> 
> If you are going to have a distinction like IR/NIR you'd better be able
> to explain it and work out which is which. We can't. It's OK for real
> world objects which "clearly" can't go down the wire[2]. But anything
> conceptual can be argued both ways - skos:Concepts, skos:ConceptSchemes,
> qb:DataSets, rdf:Properties, eg:theColourRed. 
>
> Person A: you can get your ontology / skos description / glossary entry
> down the wire, that's all there is, so they are IRs. 

OK, I can see this point.

I think your Person A is being either difficult or dense, but supposing it genuinely is that hard to draw a distinction in some case, then it is probably correspondingly unlikely that there are importantly different things to say about the putative IR and NIR, so the distinction may not in fact matter.

If that's so, then the data provider can just ignore the distinction, and make their statements about the IR.  Consumers of this data may subsequently grumble about the punning, but it won't be the worst they've seen, and it won't matter.

> Cost 3: Developer confusion/disbelief, inhibiting use
> 
> The clear cut cases like galaxies ([2] notwithstanding) are so silly
> than no one thinks this confusion could ever arise. For the less clear
> cases like skos:Concepts the discussion seems like dancing on the heads
> of pins. Followed by "if this distinction is so important why is there
> no a way to tell that I have an NIR" - the http-range-14 solution only
> says that it could be an NIR. 
> 
> The need to understand, implement and argue about this distinction
> without the benefits actually being apparent *right now* *to me* is a
> serious barrier to uptake.

I think the above argument works here, too.  If a provider can't see the distinction, they're probably not going to say anything usefully distinct about the two resources.

Perhaps that should be the resolution: "Dear Developer, there's a right way to do this, and a less right way: the right way probably gives benefit to you and is better for your data's consumers, but if you do it the other way, the world won't end.  Love and kisses, public-lod."

Is the argument actually about data _consumers_ getting confused about the distinction?  Really?  I'd have thought that, once you've grokked RDF, you're in a good place to understand the distinction fairly naturally, and in any case you are by that stage looking at a screenful of RDF which is describing a URI whose internal structure and 30xs you no longer have to care about.  I bet I'm missing a use-case.

All the best,

Norman


side issue:

> [2] You can take this line further. Arguably eg:theMilkyWay is never
> going to represent the galaxy itself, it is only ever a
> conceptualization of it and that conceptualization *can* be encoded in
> some language and sent down the wire. We are *never* really talking
> about territories we are always talking about maps and postit notes
> stuck on maps.

That is indeed arguable.  But no matter how philosophically sophisticated one is, the point of the physical sciences is indeed to talk about the territory, and not the map, matteradamn that everyone from Kant to Wittgenstein says this is impossible.  To the extent that there is a philosophy of science, as opposed to the philosophy of 'science' you find in books by that name, it has to be about the processes by which people persuade themselves that they have actually looked through that veil of perception.  (Ed: get off the damn soapbox!).


-- 
Norman Gray  :  http://nxg.me.uk
SUPA School of Physics and Astronomy, University of Glasgow, UK

Received on Thursday, 20 October 2011 11:14:01 UTC