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

I'm finding this discussion a bit puzzling. In your own closed world you 
can clearly use what ontologies you want with whatever ontological 
commitments you desire. This is obvious based on the evidence that some 
are using OWL with CWA. If using OWL meant committing to its defined 
semantics, this would not be possible.

In the open world, what you "mean" doesn't matter - it's what others 
understand. You yourself can use foaf:mbox for a shoe size, but you 
can't expect anyone else to understand that, unless, for some reason, 
through usage, that is what it comes to mean to those with whom you are 
sharing data. As with natural language we can make statements but we 
can't pre-determine what others will understand. If you wish to be 
understood in a common way, you will use your terms as they are 
generally understood. (RDF itself has many examples that show that less 
common usages are a barrier to understanding.) There is data to support 
that the terms with minimal semantics are the most used - both in 
natural language and in linked data.

As for entailments, if you make use of an ontology that has rich implied 
semantics, you can neither require nor prevent others from reasoning 
over statements you have made on the open web, regardless of what you 
prefer in terms of usage.

I don't see this as a "commitment" on the part of the creator of the 
data, because your commitment or lack thereof is not going to be visible 
- only your data will be. It's a choice, to be sure, and it has to do 
with interoperability, but on the open web your degree of commitment 
doesn't change the nature of the ontology that you use.


On 11/26/14 4:26 PM, Peter F. Patel-Schneider wrote:
> You appear to be arguing against interoperability.
> The DBpedia defining documents include an ontology.  Does that commit
> users of DBpedia-minted identifiers to the DBpedia ontology?  If not,
> why should use of foaf:mbox commmit one to the FOAF ontology, or indeed
> any portion of the FOAF definitions?
> peter
> On 11/26/2014 02:36 PM, Eric Prud'hommeaux wrote:
>> * Peter F. Patel-Schneider <> [2014-11-26
>> 07:20-0800]
>>> 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.
>> OK, let's take a fairly pessimal case and utter
>>    dbp:Deep_Blue :wonAgainst dbp:Garry_Kasparov .
>> and this peculiarly entails that Deep Blue is a dbp:Athlete.
>>    dbp:Deep_Blue a dbp:Athlete .
>> No one will have any problems consuming our little assertion unless
>> their logic somehow interacts with the wikipedia hierarchy, in which
>> case they're already marrying an ontology with known bugs.
>>> 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.
>>> peter

Karen Coyle
m: 1-510-435-8234
skype: kcoylenet/+1-510-984-3600

Received on Thursday, 27 November 2014 16:03:11 UTC