Hi Ed, (01)
> The relation is "organ is-part-of organ"; the member is a
> sentence/proposition: "my-hand is-part-of my-arm". We need to be able
> to tell that 'organ' is a term for a classifier, whereas 'my hand' is a
> term for an individual. We need to tell that the first is a vocabulary
> entry and the second is a proposition. And we need to tell that
> 'is-part-of' in the second is a reference to the vocabulary entry that
> is the first. The formal language of the ontology must make such
> distinctions and make them clear. OTOH, it is not clear to me that a
> non-normative graphical language needs to be able to represent
> propositions of the "my-hand is-part-of my-arm" kind at all. It
> depends
> on whether we need such diagrams as an aid to comprehending the
> ontology. (02)
My experience (admittedly mostly not in drawing up standards) is that we do
need this. And that there is an endemic confusion in IT between the
individual / type distinction and the specification (schema) / operation
(data) distinction. I have a few pages on this in my book (p. 260-2) where I
provide examples of individuals that are needed in specifications and types
that are introduced during operation. I think Matthew might have some
examples from standards that help to reinforce this point. (03)
>
> At the risk of opening Pandora's box even wider, I will point out that
> a
> "class whose members are classes" shows that the role "member" isn't
> necessarily played by an "individual". (Or one can say that some
> classes are individuals, or whatever your modeling language allows.)
> In
> particular, a concept that will appear in the units of measure model is
> "quantity kind", with the property that each member of 'quantity kind'
> is a subtype of 'quantity' (but not vice versa). Examples: "length",
> "duration", "mass". (04)
Agreed. And the issue here is whether the higher order types are needed
(however one might represent them). My experience, as I think I have said
before on these lists, is that a substantial proportion of reference data
schemas in application systems tends to fall into this category. (05)
At the risk of opening the Pandora's box even wider, it seems to me that you
are asking for some kind of limited base ontology. (06)
Lowe has a definition of ontology that I like, and think may be useful here.
It is ""the set of things whose existence is
acknowledged by a particular theory or system of thought." One can regard
the diagram as a system of thought - or at least a proxy for it. (07)
So when we draw these diagrams in these notations, when we ask what things
are we trying to represent, we are asking what the ontology (in Lowe's
sense) is.
So, for example, when we have an is-a relation between classes are we
representing a relation between classes or a set of (identity) relations
between their instances. (08)
> > This property is also shared by some of the other relations you
> mentioned -
> > union, intersection, etc.
...
> > - though again these can be cashed out in terms of their instances.
>
> Umm, I suppose. My point was that you don't want to confuse the
> notation for "An X can have a friend who is a Y" with the notation for
> "No X is a Y". (09)
I share your reluctance, and I think that one can extend this to a general
reluctance to interpret what on the face of it look like relations between
classes to relations between their instances. And this gives us the
beginnings of an 'ontology' for the lines on our diagrams. (010)
Regards,
Chris Partridge
Chief Ontologist (011)
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> -----Original Message-----
> From: uom-ontology-std-bounces@xxxxxxxxxxxxxxxx [mailto:uom-ontology-
> std-bounces@xxxxxxxxxxxxxxxx] On Behalf Of Ed Barkmeyer
> Sent: 13 July 2009 23:14
> To: uom-ontology-std
> Subject: Re: [uom-ontology-std] UoM ontology standard - a proposed
> program of work
>
> Chris,
>
> you wrote:
>
> > The possible semantic varieties of 'is-a' in natural language are
> quite well
> > known.
> >
> > It seems to me that you are dealing with the subsumption variety here
> (Man
> > is an Animal - all men are animals).
> >
> > Isn't there another variety that needs also to be considered - the
> > instantiation variety. Socrates is a man. (I wonder how the UML-ites
> will
> > diagram this?)
>
> In UML2, the notation for an individual is a box with an underlined
> label of the form <thing name>:<class name>, e.g., Socrates:man.
>
> But the point is exactly that: what reference concepts and reference
> relations do we want to specify as our base language? Which of those
> will we actually have graphical representations for? And will those
> graphical representations be clearly distinguished?
>
> > While one can see subsumption as a relation between instances of
> terms
> > (Every instance of A is an instance of B) - one can also see it as a
> > relation between the terms. If one takes the second course, then
> these two
> > varieties of is-a share the property of being a relation between the
> terms
> > that are linked to rather than of instances of the term. For example,
> that
> > the class of men is a sub-type of the class of animals.
>
> I think this is what Matthew was saying, and what I disagreed with.
>
> > This property is also shared by some of the other relations you
> mentioned -
> > union, intersection, etc.
>
> Yes. That was Pat Hayes' point.
>
> > - though again these can be cashed out in terms of their instances.
>
> Umm, I suppose. My point was that you don't want to confuse the
> notation for "An X can have a friend who is a Y" with the notation for
> "No X is a Y".
>
> > You mentioned relations that are between instances/members of the
> relata -
> > e.g. A -- is part of --> 1..1 B. Won't the notation also need to deal
> with a
> > -- is a part --> b or (is-part-of a b) (where a is my hand and b my
> arm).
> > Here again the relation is relating the terms rather than instances
> of the
> > terms.
>
> The relation is "organ is-part-of organ"; the member is a
> sentence/proposition: "my-hand is-part-of my-arm". We need to be able
> to tell that 'organ' is a term for a classifier, whereas 'my hand' is a
> term for an individual. We need to tell that the first is a vocabulary
> entry and the second is a proposition. And we need to tell that
> 'is-part-of' in the second is a reference to the vocabulary entry that
> is the first. The formal language of the ontology must make such
> distinctions and make them clear. OTOH, it is not clear to me that a
> non-normative graphical language needs to be able to represent
> propositions of the "my-hand is-part-of my-arm" kind at all. It
> depends
> on whether we need such diagrams as an aid to comprehending the
> ontology.
>
> At the risk of opening Pandora's box even wider, I will point out that
> a
> "class whose members are classes" shows that the role "member" isn't
> necessarily played by an "individual". (Or one can say that some
> classes are individuals, or whatever your modeling language allows.)
> In
> particular, a concept that will appear in the units of measure model is
> "quantity kind", with the property that each member of 'quantity kind'
> is a subtype of 'quantity' (but not vice versa). Examples: "length",
> "duration", "mass".
>
> The idea is to take these concerns into account in doing language
> selection. My particular position is that a non-normative diagramming
> language will help comprehension of the ontology, but it need not cover
> more than the basic features of the ontology, and what it does depict
> should not be confusing.
>
> -Ed
>
> "A picture is worth 1000 words, but it takes 10,000 words to
> recover from the 500 words that you didn't mean but people saw in
> the picture."
> -- John Day
>
>
> --
> Edward J. Barkmeyer Email: edbark@xxxxxxxx
> National Institute of Standards & Technology
> Manufacturing Systems Integration Division
> 100 Bureau Drive, Stop 8263 Tel: +1 301-975-3528
> Gaithersburg, MD 20899-8263 FAX: +1 301-975-4694
>
> "The opinions expressed above do not reflect consensus of NIST,
> and have not been reviewed by any Government authority."
>
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