Chris, (01)
Thank you for taking such trouble in responding to my vote and my
argument behind it (which I have appended in full after your full
response below). (02)
But oh dear, in your first point, starting with: (03)
> I continue to be utterly flummoxed by this argument. Do we, or do we
> not, believe ontologies can avert exactly these sorts of confusions? (04)
and ending with: (05)
> Add that axiom to your ontology, you get extensional classes. Leave
> it out, you don't. Simple, eh? :-) What *is* the controversy here? (06)
you are addressing matters which I did not raise and which are not
relevant at all to this vote Pat has called for. As Pat put it (see his
full call for a vote also in the full history below), he was asking a
"terminological question". This vote is merely about the choice of word
to use in whatever construction we end up with: "type" or "class".
(And I don't think anyone significantly disagrees as to what the concept
is which the word is to be used for.) (07)
I don't in fact think we need the word "class" at all in what we are
talking about. In my work I have no use for that word other than
perhaps as an optional synonym for "type". (08)
As your next point you had said: (09)
> Indeed, I can't even think of a colloquial use of the term "class"
> that is extensional. (010)
It does seem to me that, colloquially, any intensionality in "class" as
the product of a classification, is bottom-up from instances, or ex post
facto, or even almost coincidental. That is the colloquial
extensionality in "class" which I had had in mind. (011)
"Type" on the other hand, (in use though not in its inductive origin) is
more top-down or a priori and intentionally generic and coherent with
other such generalizations or types, all meaningful to us, and helping
us think, even though abstracted and temporarily removed from specific
instances. We must all learn to live comfortably using appropriate
generic discourse. That is where we are not merely "classifying", but
wanting to design more ideal "type"s (which, in my being-programmed
world, cohere with each other in conceptual "form"s rather than
"ontologies" (Instead of "form" I have in the past used "typology" and
later "model". And certainly never "ontology". But all that is yet
another story... )). That is surely where "type" is more apt for
ordinary people than "class"? Strange, but I have long thought that
such emphasis would also appeal to those of a formal bent...? (012)
On your final point: (013)
> > I would strongly urge us, however, not to be so influenced by such
> > perhaps confusing formal uses:
>
> It is the informal uses that are confused. We have axioms to prevent
> that sort of confusion. (014)
I am of course not alleging that the formal systems are in any way
confused or confusing in themselves. They are of course perfectly
self-contained and self-consistent... I was merely referring to the
observation by you and Leo (as I had understood it) that outsiders may
easily be confused by all the uses of "class" in various formal
definitions in various formal systems, much as in John's original point,
which triggered this whole discussion and vote, that "class" has so many
formal uses which can confuse people. (015)
On your penultimate point I have to be more controversial, though to my
great regret still rather bluntly so. Your (and Cory's) obeisance to
RDF and OWL is touchingly optimistic regarding their future success,
though at the same time strangely pessimistic regarding the power of the
eventual product of our work. For if we are successful with an
interoperability platform with universal usability at some generic
level, as I fervently believe we can be, encouraged as I am by the
long-standing continuity of my objectives and methods (incomplete though
the product still is...), well, then we shall all have no need of those
later W3C progeny. Even if there were at such a future time a
significant volume of RDF/OWL legacy applications to interoperate with,
people will choose to use any new "ontology"-based platform to translate
and absorb them in - in effect - one big automated swoop. (016)
(As I concluded my previous message: ) All that In My (not so) Humble
Opinion.
But it does at least all stand in some kind of rhetorical support of my
vote in favour of "type" rather than "class" at the basic level this
vote is all about. (017)
Christopher (018)
----- Original Message -----
From: "Chris Menzel" <cmenzel@xxxxxxxx>
To: "ONTAC Taxonomy-Ontology Development Discussion"
<ontac-dev@xxxxxxxxxxxxxx>
Sent: Friday, 20 January, 2006 19:33
Subject: Re: [ontac-dev] Type vs. Class -- Please vote (019)
On Fri, Jan 20, 2006 at 06:27:49PM +0200, Christopher Spottiswoode
wrote:
> ... (020)
Hello, Christopher, it's been a while. (021)
> Pat, my own vote goes strongly to "type" (if I may emerge albeit
> perhaps incongruously from my lurking state on this list).
> Im my own work, which I hope to release to this list and the widest
> user community at a more appropriate time, I have for many years
> consistently and insistently used "type" to denote the intensional
> sense. "Class", it seems to me (as to John Sowa), invites confusion
> with the extensional sense. (022)
I continue to be utterly flummoxed by this argument. Do we, or do we
not, believe ontologies can avert exactly these sorts of confusions?
If not, just what do we think we are doing? Looky here: (023)
(forall (C1 C2)
(if (and (Class C1)
(Class C2)
(forall (x)
(iff (instanceOf x C1)
(instanceOf x C2))))
(= C1 C2))) (024)
Add that axiom to your ontology, you get extensional classes. Leave it
out, you don't. Simple, eh? :-) What *is* the controversy here? (025)
> Having said that, I would however agree with Cory that we should try
> to conform as far as possible with what seems like colloquial use.
> But I think that that rather argues in favour of "type", as it is (to
> me at least...) more colloquially intensional than "class"! (026)
Well, at the risk of furthering the impression that this red herring of
an argument is to the point :-) , I respectfully disagree. Indeed, I
can't even think of a colloquial use of the term "class" that is
extensional. Not even "set" is extensional in colloquial usage. (027)
> I mention that because both Chris Menzel and Leo Obrst have warned us
> against using "type" because of all the uses of that word in various
> formal systems. (028)
That skews my point badly. It is not simply the fact that "class" is
the term of choice in the formal system OWL that we should use it; it is
the fact that it is in OWL AND the fact that OWL and its kin are the
primary W3C languages for publishing ontologies on the web. We're
swimming unnecessarily, indeed perversely, upstream if we choose
otherwise. Seems to me that the only thing that could justify the
choice of "type" would some definite semantic incompatibility between
the desired ONTAC notion and the W3C notion of class. But there isn't.
So if we go with "type", we force EVERY user of OWL out there who wants
to interact with an ONTAC-based ontology needlessly to worry about
translating every occurrence of "type" into "class". Similarly for
every user of any ONTAC-based ontology. Isn't the point here to
*enhance* interoperability? Why throw up this completely unnecessary
stumblingblock, folks? (029)
> I would strongly urge us, however, not to be so influenced by such
> perhaps confusing formal uses: (030)
It is the informal uses that are confused. We have axioms to prevent
that sort of confusion. (031)
-chris (032)
----- Original Message -----
From: Christopher Spottiswoode
To: ONTAC Taxonomy-Ontology Development Discussion
Sent: Friday, 20 January, 2006 18:27
Subject: Re: [ontac-dev] Type vs. Class -- Please vote (033)
Pat, my own vote goes strongly to "type" (if I may emerge albeit
perhaps incongruously from my lurking state on this list). (034)
Im my own work, which I hope to release to this list and the widest user
community at a more appropriate time, I have for many years consistently
and insistently used "type" to denote the intensional sense. "Class",
it seems to me (as to John Sowa), invites confusion with the extensional
sense. (035)
Cory (Hello again Cory!), copied below, correctly observes a rather
dominant current of practice in this connection. But I would suggest
that that usage has been unduly influenced by Object Orientation in its
programming manifestation, which most obviously deals with the
individuals, making "class" sit more comfortably with that OO user
community. (036)
The closer equivalent in our world to that OO-programming situation is
to narrow down the intensional or explicitly generic sense using
contextual qualifications until we arrive at a far more specific subtype
(such as "Customer of my product-line in my realtime") which does indeed
more obviously and validly focus on a specific subset of individuals.
But let us not by our nomenclature invite a sidelining of the benefits
of the whole intensional or "meta-" approach by such slides towards the
extensional sense, perfectly relevant and everyday though they may be. (037)
Having said that, I would however agree with Cory that we should try to
conform as far as possible with what seems like colloquial use. But I
think that that rather argues in favour of "type", as it is (to me at
least...) more colloquially intensional than "class"! (038)
I mention that because both Chris Menzel and Leo Obrst have warned us
against using "type" because of all the uses of that word in various
formal systems. I would strongly urge us, however, not to be so
influenced by such perhaps confusing formal uses: the inventors of
formal systems are endlessly inventive in their specialized uses of
colloquial words. (The use of "institution" in category theory comes to
mind as an extreme yet here relevant example. Nice though that
specialization is, the sociologists continue to use the term in their
own also specialized yet far more colloquial sense, and without any
confusion by the CT usage.) (039)
All IM(not so)HO. (040)
Christopher (041)
----- Original Message -----
From: "Cory Casanave" <cbc@xxxxxxxxxxxxxxxxxxxxxxx>
To: "'ONTAC Taxonomy-Ontology Development Discussion'"
<ontac-dev@xxxxxxxxxxxxxx>
Sent: Friday, 20 January, 2006 15:54
Subject: RE: [ontac-dev] Type vs. Class -- Please vote (042)
Pat,
As stated, I have a preference for "type" - it is, to me, less confused.
BUT, there may be a more important factor and one that implies a prior
commitment - the semantic web. (043)
The semantic web (Essentially RDF) and to a lesser but still significant
extent OWL is a major factor in the industry. It is the leading factor
that is making Ontologies more mainstream. If there is any question
that there will, at least, be an OWL view of COSOMO then I am on the
wrong list as my concern is doing things that will be used and have an
impact (in my lifetime). (044)
I recognize the limits of OWL and the somewhat low opinion of it held by
sophisticated logicians such as are contributing to this list, and as I
have learned more I have started to share that opinion. But, broad
acceptance of COSMO will be a social and economic phenomena, not a
logical one. (045)
In addition, there are some features of the semantic web that would be
of great benefit - it is the only logical system that I know of that
that provides an infrastructure for widely distributed and federated
ontologies. These capabilities could be applied to the semantics of CL
just as well as they apply to OWL. (046)
Given a lattice/modular approach there can be mechanisms for having an
OWL view with "modules" that depend on more sophisticated logics. If
so, we can have the best of both. If we adopt the axiomatically slim
core John suggests, it could be expressed in OWL. (047)
So perhaps it is important to understand how COSMO will be part of the
semantic web and in doing so not impose the confusion of an arbitrarily
different terminology. This would suggest "class" and the other OWL
terms be used where possible and that we not conflict with that
terminology. Therefore, reluctantly, that is my vote. (048)
-Cory Casanave (049)
-----Original Message-----
From: ontac-dev-bounces@xxxxxxxxxxxxxx
[mailto:ontac-dev-bounces@xxxxxxxxxxxxxx] On Behalf Of Cassidy, Patrick
J.
Sent: Friday, January 20, 2006 2:45 AM
To: ONTAC Taxonomy-Ontology Development Discussion
Subject: [ontac-dev] Type vs. Class -- Please vote (050)
I would like to get a sense of this group on a terminological question.
If you have any preference at all, please send me a note directly. (051)
The question was raised regarding what the ONTACWG community should
call those intensionally-defined groupings called: (052)
Class in Ontolingua and Protege
Class in RDF and OWL
Class in SUMO
Collection in OpenCyc
Universal in DOLCE
Property in Ontology Works' IODE system
--------------- (053)
The only contenders put forward are:
Type
Class (054)
if "type" then the subsumption relation will be subtype
if "class" then the subsumption relation will be subclass (055)
There have been a few expressions of support for each alternative.
It looks like time to resolve the question by vote. (056)
Unless you want to express some opinion regarding this to the list, it
will be best to send me the reply directly to avoid overloading. (057)
Pat (058)
Patrick Cassidy
MITRE Corporation
260 Industrial Way
Eatontown, NJ 07724
Mail Stop: MNJE
Phone: 732-578-6340
Cell: 908-565-4053
Fax: 732-578-6012
Email: pcassidy@xxxxxxxxx (059)
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