Hi Ed,
I agree much of what you say, but would add that there's 100%
certainty that your understanding of Concept:A is differs from my
understanding. A 'close enough' practical view of reuse is what
drives my approach in this matter. In fact many ontologists (and
programmers!) mechanistically subclass/subproperty each item in a
reused component, specifically to allow for specializations
(interesting that there's no subindividuation possible that I know
of).
Getting to your defense of Doug's view that RDF is so lacking it's
useless for functionally distinguishing between concepts, I am still
replying that that's irrelevant to my critique. Let me restate my
critique here.
- (a) If FOL representation is the ideal, then RDF as an FOL
subset should conform with its rules
- (b) The rule for FOL representation is that FOL predicates are
coordinate with predicators
- (c) RDF properties are -- far far too often -- not conforming
to this rule for FOL predicates
-
(d) RDF predicates (during ingestion) must be transformed to FOL
predicates when non-conforming
- (e) When not so transformed, FOL predicates are being created
that break FOL rules
Consequently the sets of FOL and RDF predicates have exploded to
unuseable sizes.
Again, the tools are not the problem -- predicates are the problem.
In particular, nounal predicates which flagrantly break the rule for
FOL predicates.
/jmc
On 1/23/2014 11:33 AM, Barkmeyer,
Edward J wrote:
John,
I beg to differ. It is not just about how we name things; it is about how we know what is being named.
A useful taxonomy is based on well-defined properties. So the capabilities of the chosen syntax make a difference. Can you phrase: "An X is a Y that does (or does not) have property P" in the syntax you choose? Alternatively, can you phrase: For all X's, sentence S1 (about X's) is true?. These are the established structures for formal definition. Ultimately, there must be some terms that are "primitive", in that we can't define them formally in terms of other concepts or axioms. But if all or most of your terms are primitive, no one can be really sure what any of them mean.
I think it is quite reasonable to consider whether you want to use someone else's formal (e.g., RDF) term for something that the source defines loosely in English from his/her particular point of view. You have to determine that the definition is unambiguous, in terms of the definitions of the English words used and the syntactic (and pragmatic) context of their use. Then you have to determine whether that is exactly what you mean for your particular purposes.
For example, suppose we define the IRI http://mydictionary.com#food as "anything people eat". Why "people"? (Why do we call it "dog food" -- is that a misnomer?) Which people did the author have in mind? Does that include grasshoppers? Does it include grass? Do you really want to use his term, thereby implying that anything anyone says about ...#food is consistent with what you say about ...#food? That is the problem.
The ISO TC37 "terminology" folk would say that agreement to use a set of terms consistently creates a "speech community" who have a "shared understanding" of the meaning of the terms, insofar as they are used within that community. So "reuse" is a property of terms WITHIN a community. The problem with RDF (and the Semantic Web in general) is that construction/development of those communities is left as an undefined social exercise.
Doug's point is that it is very difficult in RDF (mostly impossible) to say what you do and do not mean by ...#food. As a consequence, it is very risky for me to assume that what you mean and what I mean are (exactly) the same, unless there is some community of use that I know we both belong to (and we keep out, disparage, vilify the riffraff who misuse OUR terms). There are some thriving speech communities using RDF, but their vocabularies are not very large, because the language itself doesn't much help in creating the shared understanding. OWL is more expressive than RDF, and you can write (some) formal definitions and axioms in OWL, but it takes real dedication to do that wherever possible and get it right. So, OWL has a combination of RDF-like communities, who formalized the terms and develop the common understanding by informal means, and a few communities whose terms are rigorously defined, and a few communities who aspire to the latter and are still learning how
to do it.
The point is that these "reuse" communities arise by choosing a language (syntax) and a set of practices that they all agree to be comfortable with. The shared understanding is the "content", but the means of _expression_ is part of the shared practice that begets and maintains the shared understanding. You can separate content from syntax in your own head, but you cannot separate content from syntax when you communicate with others. Syntax, of some kind(s), is critical to creating the "shared understanding" of a term.
-Ed
--
Edward J. Barkmeyer Email: edbark@xxxxxxxx
National Institute of Standards & Technology
Systems Integration Division
100 Bureau Drive, Stop 8263 Work: +1 301-975-3528
Gaithersburg, MD 20899-8263 Mobile: +1 240-672-5800
"The opinions expressed above do not reflect consensus of NIST,
and have not been reviewed by any Government authority."
-----Original Message-----
From: ontology-summit-bounces@xxxxxxxxxxxxxxxx [mailto:ontology-
summit-bounces@xxxxxxxxxxxxxxxx] On Behalf Of John McClure
Sent: Thursday, January 23, 2014 12:04 PM
To: ontology-summit@xxxxxxxxxxxxxxxx
Subject: Re: [ontology-summit] The tools are not the problem (yet)
On 1/22/2014 10:47 PM, doug foxvog wrote:
<snip/>
"Reuse" was the promise; empirically it has not been delivered - why not?
Because it was expressed in RDF.
Let's not confuse format with content.
+ Class taxonomies + Property taxonomies
If you hate CycL, pick another format. -- doug
Format is not the issue. It is how we name things.
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