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RE: Stipulative Ontologies

From: Pat Hayes <phayes@ihmc.us>
Date: Tue, 6 Apr 2004 12:21:54 -0500
Message-Id: <p06001f13bc9890e2e887@[]>
To: "John Black" <JohnBlack@deltek.com>
Cc: <public-sw-meaning@w3c.org>

>  > From: Bijan Parsia [mailto:bparsia@isr.umd.edu]
>>  Sent: Monday, April 05, 2004 9:02 PM
>>  On Apr 5, 2004, at 8:24 PM, John Black wrote:
>>  > A consideration, relevant to these discussions, is the degree of
>>  > control desired by the author over the meaning of a semantic web
>>  > document.
>>  And the degree of control possible.
>>  Plus, the degree of control *other* people have over *my*
>>  document, if
>>  I use "their" URIs.
>Control over meaning is possible and frequent.  For example, """In the
>following triple, let x = "JohnBlack"; let y = "is"; and let z = "correct".
>Here is the triple: :x :y :z. """  My meaning for x, y, and z is clear,
>unambiguous, and undisputable due to the stipulative definitions I provided.

But you didn't, and it isn't. What exactly do you mean by "correct", 
for example? (Do you have a correctness ontology somewhere?)  And is 
there only one John Black on the entire planet? So which of them are 
you referring to?  etc..

More generally, setting out to define OWL meanings by reference to 
English words is hopeless. It is impossible to capture the full 
meaning of any English word in any piece of OWL; but on the other 
hand, the precision of meaning that can be achieved by OWL exceeds 
that of the most careful English statement. Formalisms like OWL treat 
URI meanings like very thin needles, whereas English words are like 
wide, flexible plastic sheets. They are just incomparable.

>It would be silly for you to come along and say, """I dispute that what
>you meant by x was "JohnBlack", In fact, what you meant by x was
>"BijanParsia"! """  Of course, the truth value of the overall triple is
>debatable, in either case, but *my* meaning is under *my* control.

You intended meaning may indeed be under your control (though I bet I 
can produce doubt in your mind by a bit of Socratic questioning), but 
your intentions are kind of irrelevant since you can't transmit them 
over a Web. What you can transmit is OWL, and the meaning of THAT is 
determined by the OWL model theory. That's all that you have. Now try 
doing some stipulation.

>  > > It seems to me desirable to add a feature, or to create an
>>  application
>>  > that allows an author to publish how much of an ontology should be
>>  > treated
>>  > as stipulative and how much as lexical or descriptive.
>>  All of an OWL ontology is, save for comments, stipulative.
>>  I'm not sure
>>  what you mean by lexical.
>Is the RDF version of Wordnet, http://www.cogsci.princeton.edu/~wn/, "a
>lexical database for the english language." an example?

No. Wordnet is a network of English words, not an ontology. Nothing 
in Wordnet tells you what any of the words *mean*.  Of course, being 
an native English speaker, you kind of know what they mean, but OWL 
isn't designed for native English speakers.

>A lexical definition reports on the way a term is used.  It describes
>the meanings of terms as found in existing statements.  The difference
>between descriptive definitions and stipulative definitions is the
>difference between describing and prescribing meaning.  I can see many
>uses cases of ontologies being lexical, trying to capture some existing
>terminology and formalize it in owl.  But I can also see many use cases for
>the opposite, stipulative ontologies, where new terms are created or
>existing terms are appropriated and their meaning, in the context of the
>authors statements, is stipulated. 
>>  > I believe the lack of this is at the heart of some of the debate on
>>  > this list.
>>  > I think that some users of RDF assumed that by default most
>>  ontologies
>>  > would
>>  > be taken as stipulative definitions of terms (URIs) owned by the
>>  > author.
>>  Of terms, sure. Owned by the author, no. At least, if you take that
>>  literally, it's not only not done, but highly undesirable.
>>  You couldn't use *anyone* else's URIs in your ontology!
>Perhaps we could say authorship, and compare it to citation.  I can
>quote your paper, but I should put it in quotes and include a citation
>so my readers can look it up and read for themselves what you meant.
>This respect for your meaning, by citing your entire paper, does not
>prevent me from using quotes from your paper.  In fact, it makes it
>more valuable.  I don't have to redo all your definitions, propositions,
>or arguments.  I can use your conclusions and cite the rest.

Look, NONE of these metaphors are relevant. The entire business of 
handling formal ontologies and asking about their meaning is quite 
unlike the business of communication between speakers of a natural 
language. If its like anything, it would be more like a kind of 
primitive telepathy but between intellects about the size of a 

>>  > Others
>>  Methodological point: Who are these "users"? If you are referring to
>>  debates on the list, it would help to point to threads or mention
>>  names.
>I will look for these. 
>>  > saw that much of natural language was based on uses that could only
>>  > later be formalized into descriptive definitions instead. 
>>  They were
>>  > afraid
>>  > that we were headed down a road requiring software to treat all
>>  > ontologies as
>>  > stipulative, and thus missing the chance to create terms that could
>>  > evolve
>>  > naturally.
>>  Not me. Stipulations can evolve.
>>  [snip]
>>  > Stipulative definitions are used quite often in statutory law,
>>  > contracts,
>>  > programming languages, and standards documents.  They are used, it
>>  > seems,
>>  > wherever the advantages of reduction of ambiguity and increased
>>  > precision are desired.  They have disadvantages as well,
>>  and certainly
>>  > need not be used everywhere.
>>  One thing I've held out for is the propriety of is a document author
>>  being allowed to stipulate the meaning of *all* the URIs in her
>>  ontology (well, at least ones that aren't part of the syntax
>>  of OWL or
>>  RDF).
>This distinction is perfect.  The meanings of the key words of the syntax
>are stipulative

Not in the same sense as a stipulative legal text in English. The OWL 
keywords have a meaning provided by a model theory. The nearest 
English equivalents would be the closed-class function words (is, 
and, not, and so on)  and the grammatical auxiliaries such as the 
'will' for future tense. These are usually considered to be immune 
from stipulative definition.

>, and it would be pointless to dispute the meanings defined
>for them, if we are to use RDF or OWL as so defined.  Their value is due
>to everyone's acceptance of the stipulated meanings.  On the other hand,
>to the extent that everyone's meaning was always stipulative, there could
>be no dispute over meanings.  For it is pointless to dispute stipulative
>definitions, they cannot be wrong, by definition.

But, critically, they can be incomplete. Ontology sharing depends on 
this observation. English doesnt offer a good analogy to this.

>To use a programming language example, rather than natural language,
>If we were to use OWL to define a programming language with an ontology,

I doubt if that would be possible. For example, there is no way to 
specify a minimal fixedpoint operator (needed for the meaning of 
recursion or iteration) in OWL.

>we would need the ability to define the keywords stipulatively.
>>  > I believe we can formalize and thus automate the
>>  specification of the
>>  > degree
>>  > of stipulation we desire over our ontologies and thus meet
>>  the needs
>>  > of both
>>  > those who think that the author/owner of URIs should be able to
>>  > stipulate
>>  > the meaning intended by publication of those URIs in
>>  certain contexts
>>  > and
>>  > those who think the meaning of URIs should be free in all
>>  contexts to
>>  > evolve
>>  > naturally towards whatever future they may have.
>>  >
>>  > Having the explicit facility to do this will not inhibit
>>  either goal.
>>  It will inhibit me disagreeing with your stipulations, or overriding
>>  your (from my perspective) erroneous stipulations.
>One's stipulative definitions are not disputable, nor can they be wrong.
>>  I don't think you've hit on the key to any debate on this list that I
>>  am aware of. Again, perhaps a pointer or some names of players would
>  > help clarify?
>During many debates, you** have used the freedom to dispute the meaning
>of an authors URI as the concluding argument against proposals for
>controlling the meaning of a URI an author wants to establish for it. 
>In particular, you just did so above when you said such a facility would
>"""...inhibit me from disagreeing with your stipulations...""".  I'm saying
>that to the extent I use stipulative definitions it is pointless to dispute
>them.  The meaning of my URI so defined is just what I say it is in the
>context of my statements and the statements of all who accept my stipulated

You are here presuming a social setting in which the stipulative 
definition has a certain role. But this social setting is not 
applicable to web ontology traffic, so your point loses its force. It 
is always possible for one agent to disagree with another. The  Web, 
however, unlike English, provides a way to follow any name to its 
source, which allows readers to determine which sources are more 
definitive than others. If English were like this, we could all, just 
by reading a word, know everything that its inventor wished us to 
know about the meaning he had in mind. In this case, the entire 
apparatus of stipulative definitions would be largely unnecessary: 
rather than set out to attach a special meaning to an existing word, 
one would just use a new word.    English of course is not like this, 
so we have a different way to share meanings which depends on 
flexible social agreements which at times need to be explicitly 
denied or over-ridden. However, to repeat, the semantic web is not 
like a bunch of people talking in English.

Pat Hayes

>>  Cheers,
>>  Bijan Parsia.
>**If you really feel your position is being misrepresented, I apologize, and I
>will look for particular citations to refer to, or stand corrected.
>John Black.

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Received on Tuesday, 6 April 2004 13:23:00 UTC

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