Re: interoperability (was Re: isolating shapes in named graphs)

On 11/26/2014 05:46 AM, Eric Prud'hommeaux wrote:
> * Peter F. Patel-Schneider <> [2014-11-26 05:11-0800]
>> One usually uses an external URI, like foaf:mbox, because one wants
>> interoperability of meaning.  However, I do not believe that
>> complete interoperability of URI meaning should be mandated.  I also
>> do not believe that complete interoperability of URI meaning is
>> possible.
>> Further, I believe that effective interoperability can be achieved
>> without mandating use of defining definitions.  For example, I may
>> decide that I don't want to use the "static" part of the definition
>> of foaf:mbox. Interoperability should remain for most purposes.
>> Particular commmunities can, if they want,  require stronger
>> conditions on shared meaning.  Perhaps it would be possible to set
>> up a community that achieves complete interoperability of meaning.
>> However, I very strongly believe that "the web" cannot be such a
>> community, and thus that W3C recommendations should never mandate
>> it.
> It sounds like if I'm not feeling lucky, I should never consume data
> from anyone with whom I've not written up some contract. What would
> that contract say? "I agree to use the vocabularies according to their
> documented semantics. I will not use terms if I don't understand their
> semantics."

I don't think that you have to have a direct contract with that other party. 
There could be some out-of-band information about that other party, for 
example that they are a participant in some community.  There could also be 
information in documents, such as the use of logical properties, like rdf:type 
or owl:imports.  Sure a particularly perverse player could use these 
properties differently than you expect, either intentionally or inadvertently, 
but using logical properties in a non-standard fashion is something that 
should only be done, in my view, with great trepidation.

(Of course, I'm actually going against web practice here somewhat.  There are 
many situations where logical properties are not used correctly.  Consider 
owl:sameAs, for example.)

>> Merging data from different sources can be problematic even if the
>> use of defining definitions is mandated.  Data can be incorrect,
>> after all.
> I suspect you are being a bit provocative here,

Not at all, I've held this position from the very beginning of my involvement 
with the semantic web.  I and others have forcefully argued it at various 
meetings, and have affected W3C recommendations thereby.

> and I'm playing along
> nicely. Surely we needn't jettison this fine bathwater just because
> it's slightly sullied by a baby. It's quite practical to say that I
> will respect, or at least not contradict, the properties of foaf:mbox
> even if there's an assertion elsewhere in that ontology that the moon
> is a subclass of Things made of green cheese. What's the actual
> screw-case if I use <>?

Well, you do commit to lots of unusual things in this case.  For starters, 
there are several minimum and maximum temperatures.

If you commit to the DBpedia ontology you get a number of unusual 
consequences, like Berlin being a mountain and Lambeau Field being a city. 
You also commit to unusual definitions of many categories.  For example, all 
windmills are buildings, all libraries are educational institutions, chess 
players are athletes, saints are clerics, baronets are british royalty, 
professors are scientists.

I care about this sort of thing because I want to use the consequences of web 
information in my systems.  I don't want to have to commit to too much, 
however.  I also want to be able to commit to some things and see when the 
sources that I do use have committed to other things.  I certainly don't want 
to have to commit to the entire web to use any of it.


Received on Wednesday, 26 November 2014 15:20:49 UTC