Re: Squaring the HTTP-range-14 circle [was Re: Schema.org in RDF ...]

"A step too far"?

Hi.
I've sort of been waiting for someone to say:
"I have a system that consumes RDF from the world out there (eg dbpedia), and it would break and be unfixable if the sources didn't do 303 or #."
Plenty of people saying they can't express what they want without it.
And plenty of people saying they can't write some code that they might not be able to understand some RDF they receive properly.
But no actual examples in the wild (at least as far as I can tell in a lot of messages).

This might be for quite a few reasons, such as:
1) There are no such consuming systems;
2) The existing consuming systems would not break.

Number (1) would be too embarrassing, and is wrong because I have some, so I'll think about number (2).

There seem to be some axes in the discussion:
publish / consume
long/medium term / shorter term
ideal / pragmatic
Interestingly, we don't seem to have a strong theory / practice axis, which is great.

As a publisher, I/we have had to work pretty hard to conform to really quite complex requirements for publishing RDF as Linked Data; not just Range-14, but voiD, sitemaps and various bits and pieces that Kingsley always tells me to do in the RDF.
As a consumer, it has been pretty simple: "Well guv, thanks for the URI, here's some RDF."
It has always been something of a source of angst (if not actual pain) to me that none of the extra work I put into publishing RDF is ever used by me or anyone else, as far as I know.
In fact, some of the sites I consume actually don't do things "properly" - I might have had to change my consuming systems to cope with this, but I don't, because they already cope fine.
Why is it not a problem? One obvious reason is that the consuming application is actually looking for specific knowledge about things.
I don't have a consuming system that is considering both lexical and animal subjects, and so confusion does not arise.
In fact, it is the predicates that tend to distinguish satisfactorily for me (as has been pointed out by some people).
Thus, if I get a triple that says the URI that would resolve to my Facebook page foaf:knows the URI that would resolve to your Facebook page, I (my system) will happily interpret that as one person (or whatever) foaf:knows the other. I certainly don't want to go and resolve these to find out to what the URIs actually resolve. And if I did, what would I do about it? Ignore it?
In fact, as has also been mentioned, you can define domains, ranges and restrictions for as long as you like, but it is quite possible and likely that the users of URIs will continue blissfully unaware of any of this, in exactly the same way that they continue unaware that there might be something ambiguous about the URIs they are using.

By the way, as is well-known I think, a lot of people use and therefore must be happy with URIs that are not Range-14 compliant, such as http://www.w3.org/2000/01/rdf-schema .

When we help people publish, it really is tough to engage them long enough to care about the complex issues, and they often get it wrong - I am engaged with quite a few people who are now publishing serious amounts of interesting RDF where I have contacted them to try to help. The status of the conversations is that they have fixed what they can, and are now thinking (for a long time) about how they might configure their systems to do it properly - but they may never get there. I will still want to use their RDF.

So, trying to be a little brief:
I have always felt that the full Range-14 distinction was in danger of being a Step Too Far.
Yes, it does matter, and it is likely (or at least possible) we will pay a price in the end.
But the world is trying to pass us by - it has at least pulled alongside.
We must work out why we seem to have lost any lead we had, because it is likely to be the same reason we will get left behind.
And I happen to believe that what we have can be better than the alternatives.

Sorry Pat, I don't actually have a proposal.
But I do know we need to be liberal in what we consume.
And we might need to be a bit more liberal in what we praise, or at least be nicer to people who want to publish RDF and don't do Range-14.

Best
Hugh

On 19 Jun 2011, at 05:05, Pat Hayes wrote:

> Really (sorry to keep raining on the parade, but) it is not as simple as this. Look, it is indeed easy to not bother distinguishing male from female dogs. One simply talks of dogs without mentioning gender, and there is a lot that can be said about dogs without getting into that second topic. But confusing web pages, or documents more generally, with the things the documents are about, now that does matter a lot more, simply because it is virtually impossible to say *anything* about documents-or-things without immediately being clear which of them - documents or things - one is talking about. And there is a good reason why this particular confusion is so destructive. Unlike the dogs-vs-bitches case, the difference between the document and its topic, the thing, is that one is ABOUT the other. This is not simply a matter of ignoring some potentially relevant information (the gender of the dog) because one is temporarily not concerned with it: it is two different ways of using the very names that are the fabric of the descriptive representations themselves. It confuses language with language use, confuses language with meta-language. It is like saying giraffe has seven letters rather than "giraffe" has seven letters. Maybe this does not break Web architecture, but it certainly breaks **semantic** architecture. It completely destroys any semantic coherence we might, in some perhaps impossibly optimistic vision of the future, manage to create within the semantic web. So yes indeed, the Web will go on happily confusing things with documents, partly because the Web really has no actual contact with things at all: it is entirely constructed from documents (in a wide sense). But the SEMANTIC Web will wither and die, or perhaps be still-born, if it cannot find some way to keep use and mention separate and coherent. So far, http-range-14 is the only viable suggestion I have seen for how to do this. If anyone has a better one, let us discuss it. But just blandly assuming that it will all come out in the wash is a bad idea. It won't. 
> 
> Pat
> 
> On Jun 18, 2011, at 1:51 PM, Danny Ayers wrote:
> 
>> On 17 June 2011 02:46, David Booth <david@dbooth.org> wrote:
>> 
>>> I agree with TimBL that it is *good* to distinguish between web pages
>>> and dogs -- and we should encourage folks to do so -- because doing so
>>> *does* help applications that need this distinction.  But the failure to
>>> make this distinction does *not* break the web architecture any more
>>> than a failure to distinguish between male dogs and female dogs.
>> 
>> Thanks David, a nice summary of the most important point IMHO.
>> 
>> Ok, I've been trying to rationalize the case where there is a failure
>> to make the distinction, but that's very much secondary to the fact
>> that nothing really gets broken.
>> 
>> Cheers,
>> Danny.
>> 
>> http://danny.ayers.name
>> 
>> 
> 
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-- 
Hugh Glaser,  
              Intelligence, Agents, Multimedia
              School of Electronics and Computer Science,
              University of Southampton,
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Received on Sunday, 19 June 2011 11:06:32 UTC