Hi Pat, (01)
As you know, I reckon a top level ontology is useful, but I have some
reservations (rather than disagreements) about your comments. (02)
Firstly, would you be happy with your readers seeing 'intended meaning' as
roughly speaking dividing into the 'formal semantics' and the 'intended
interpretation'. So, I presume that when you say " it is the *intended
meanings* of the ontology elements that are of primary importance", you
intend this to mean both the 'formal semantics' and the 'intended
interpretation' - unless you are adopting another theory of meaning.
If you recall, I suggested that the 'intended interpretations' may be
portable. (03)
So where you say " I think that fixing the intended meanings of the
primitives will be a high priority", this will involve both giving the
axioms and some other mechanisms to tie down the intended interpretation -
as both of these are components of the meaning? (04)
I am not sure how to explain my reservations briefly, but I will try.
I think the man on the Clapham omnibus does not have a sufficient good idea
of the intended meaning (or intended interpretation) of the terms he (and
we) use for their deployment in computer systems. So I believe an important
part of ontology building (and more generally of designing computer systems)
is characterising these better.
An extremely important way of doing this is devising the axioms (or however
one wishes to characterise the formal structure) that characterise the
intended meaning and so the intended interpretation (of a formal semantics). (05)
There are other techniques, such as the metaphysical considerations I raise
from time to time (Note to PatH - I know you violently disagree, so can we
take your criticism as read (for those that are not aware see the
archives)).
However, I do not think we are mature enough to be sure we have made all the
right decisions (including the right metaphysical choices), particularly for
large ontologies.
I think that, among other things, these need to be subjected to empirical
test, which has not really happened yet. (06)
So I think that though the goal of a stable standard it is not really
achievable in the short term. I prefer to think of the top ontology I work
with as a reference ontology that an engineer will deploy if she/he thinks
it will work in the situation. Over time a standard may evolve, but we need
to wait for that. (07)
I suspect you think that the semantic primitives are to be found in Longmans
(or some other natural language source). If only it was so easy. My belief
is that you are asking an old technology to solve a new technology problem -
thinking in terms of horseless carriages when we really need cars. To get
some idea of what I mean look at the literature on orality and literacy
which studies previous 'information revolutions' - unless like Henry Ford
you believe history is bunk! (08)
You said " but there may still be references to instances and other
> documentation, not formally reflected in the ontology structure, that
help the
> ontologist and programmer to avoid making changes that cause unintended
and
> undesirable consequences in programs." (09)
If I have understood this correctly, then I believe that this may be a
common bad practice in ontology development.
It makes no sense to me to include in the 'documentation' stuff that can
easily be incorporated into the ontology - at least at the analysis stage.
So, for example, given how easy it is to record 'instances' these should be
put into the ontology.
It may turn out that a more important consideration is to translate the
formal structure into text to make it more readable for the users - ISO
19526 does this (though you may find the English a bit stilted).
My gut instinct would be to formalise where possible for explanatory reasons
- I think these are at least as important in large ontologies as inference. (010)
Regards,
Chris (011)
> -----Original Message-----
> From: ontolog-forum-bounces@xxxxxxxxxxxxxxxx [mailto:ontolog-forum-
> bounces@xxxxxxxxxxxxxxxx] On Behalf Of Patrick Cassidy
> Sent: 02 March 2010 12:37
> To: '[ontolog-forum] '
> Subject: Re: [ontolog-forum] Foundation ontology, CYC, and Mapping
>
> Chris, Matthew,
> You have both expressed the point I was making better than I did, and I
agree
> with your comments. Even so, I can't resist trying to summarize again by
first
> reiterating the starting point for this thread about meaning. ( the emails
from
> ChrisP and MatthewW are included below my signature for reference if
needed):
> (1) In order to support general accurate semantic interoperability the
> Foundation Ontology should be as stable as possible. That is why I think
an
> effort to identify as many as possible of the semantic primitives should
be one
> priority of the early phase, to minimize the need for subsequent changes
to the
> FO.
> (2) PatH and JohnS have pointed out that the "meanings" accessible to the
> computer's reasoning mechanism are the total sum of all inferences, which
> change in some way (perhaps only by addition) when any change is made to
the
> ontology. No disagreement.
> (3) But recognizing that the goal of the FO is to support the purposes of
the
> programmers and ontologists who use it in applications, it is the
*intended
> meanings* of the ontology elements that are of primary importance, because
> they determine what goes into the ontology. The users are not at the
mercy of
> any unintended inference that, willy-nilly, may pop up when a change is
made to
> the ontology; if the behavior of the programs using the ontology shows
that the
> meanings accessible to the computer that affect program behavior have
> changed in some *undesirable* way, then that change to the ontology must
be
> rescinded or additional modifications made to bring the behavior of the
> programs back to that desired. It is the intended meanings of the
ontology
> elements that determines what inferences will be made by the ontology, not
> vice-versa, because the ontologist is in control of both. The intended
meanings
> *can* and *should* be stable, and the ontology should express those
intended
> meanings.
> So saying that the intended meanings of the ontology elements should be
> stable, and also saying that the computer only knows the meanings
supported by
> the logic of the ontology, are not contradictory. The logical inferences
are
> critical in determining what the computer can do with an ontology, but the
> intended meanings of the ontology elements constrain what can go into the
> ontology - and therefore what inferences will be made. For the FO
approach to
> interoperability, I think that fixing the intended meanings of the
primitives will be
> a high priority. It is desirable to formalize those intended meanings as
precisely
> as possible, but there may still be references to instances and other
> documentation, not formally reflected in the ontology structure, that
help the
> ontologist and programmer to avoid making changes that cause unintended
and
> undesirable consequences in programs.
>
> And of course we cannot expect perfection from this strategy, but I think
we will
> get *closer* to general accurate interoperability by this tactic than by
just
> mapping domain ontologies to each other. I also expect FO-base
> interoperability to be faster and cheaper than alternatives.
>
> Pat
>
> Patrick Cassidy
> MICRA, Inc.
> 908-561-3416
> cell: 908-565-4053
> cassidy@xxxxxxxxx
>
> =============================================================
>
> [[From Matthew West]]
> Dear PatH and PatC,
>
> Let me have a go at this.
>
> > > The disconnect between PatH's view of "meaning" and mine is that
> > > he is content to believe that the meanings of the elements used in
> > programs,
> > > databases, ontologies (e.g. time, distance, physical object, dollar,
> > > person)
> > > all change every time we add a new assertion about unicorns, and I
> > > am not.
> >
> > It is not a matter of being content to believe. I am asserting this AS
> > A FACT, and you are simply in denial about elementary facts of
> > semantic theory. Now, of course, you are free to invent an alternative
> > semantic theory, one that supports your intuitions about meanings
> > being fixed when axioms change, but I would like to see that theory
> > given some reasonably precise flesh before proceeding to discuss this
> > matter very much further.
>
> MW: I suspect the real problem here is that you are each looking through
> opposite ends of the telescope. Let me describe the different views:
>
> PatH looks at it from the theory end, and says that when you change an
axiom in
> a theory there is a different set of models that it picks out. Absolutely
right. It
> "means" something different.
>
> PatC looks at it from the other end. He has a particular intended
interpretation,
> and his question is: if he changes this axiom does it still pick out his
intended
> interpretation (he doesn't care about any unintended interpretations). If
it does,
> as far as he is concerned it "means" the same thing. Also true.
>
> I think there is something to be accommodated from both sides here in
practical
> ontology development
>
> Regards
>
> Matthew West
> Information Junction
> Tel: +44 560 302 3685
> Mobile: +44 750 3385279
> matthew.west@xxxxxxxxxxxxxxxxxxxxxxxxx
> http://www.informationjunction.co.uk/
> http://www.matthew-west.org.uk/
>
> ==========================================
> [[From Chris Partridge]]
>
> > -----Original Message-----
> > From: ontolog-forum-bounces@xxxxxxxxxxxxxxxx [mailto:ontolog-forum-
> > bounces@xxxxxxxxxxxxxxxx] On Behalf Of Chris Partridge
> > Sent: Tuesday, March 02, 2010 4:24 AM
> > To: '[ontolog-forum] '
> > Subject: Re: [ontolog-forum] Foundation ontology, CYC, and Mapping
> >
> > Pat,
> >
> > I agree that it is a common fallacy to somehow assume that the
> > computer can read our intentions - and it is important to check we are
> > not making it (and to point it out when we see it).
> > And that the formal ontology we give the computer has a formal
> > semantics that may constrain the intended interpretation, but does
> > not (and is not intended to) capture it.
> >
> > My intention was to make (in a sense) the inverse point - that when we
> > build an ontology it is a similar fallacy to say we are only
> > interested in the formal semantics. (Does anyone on the list think
> > this is not a fallacy?
> > I
> > have met people who do.)
> >
> > (To reiterate your buggy software point below a little more
> > prosaically, but hopefully accurately.) When we construct the ontology
> > we have an intended interpretation - if we are building a financial
> > ontology when we add axioms about equities, we have an intended
> > interpretation for 'equities' and we judge whether the axioms make
> > sense in terms of this interpretation.
> > Similarly, when we deploy the ontology, we use it to work with the
> > intended interpretation - we would not normally deploy the financial
> > ontology in, say, an offshore oil processing system and interpret
> > 'equities' as oil rigs.
> >
> > So, clearly, without an intended interpretation, the ontology is of no
> > practical use.
> >
> > This seems to me to imply that when we are thinking about the process
> > of developing an ontology, it is useful to have some way of talking
> > about and sharing this intended interpretation. In the scenario you
> > describe below, where you are the (only) person writing the program
> > then " My intended behavior is quite clear", but in larger teams and
> > where external QA is required - more of a framework is needed. So the
> > 'intended interpretation'
> > can be practically formalised the better - it is not a good strategy
> > to dismiss it as subjective and irrelevant. (The notion of intended
> > interpretation is a good starting point.)
> >
> > I suspect this is partly why PatC (and others) make some of the points
> > they do (PatC, feel free to tell me I am mistaken).
> >
> > If one can agree an intended interpretation for a FO (or some high
> > level elements of one) then this is inherited by the sub-types - so it
> > is a cost-effective mechanism for tying down the interpretation. (As
> > an aside, my gut feeling is that PatC's strategy for doing this is not
> > going to bear fruit - but it is good research to explore the options.)
> > At the lower level, if one can agree the intended interpretation for
> > some terms with a high degree of certainty (which may require some
> > work) - then this is independent of the theory/ontology the terms are
> > embedded in and is portable across them.
> >
> > Where this works well is with proper names (especially if you assume a
> > direct reference theory (an intended interpretation?)).
> > It works less well where the terms (in the wild) come with
> > connation/sense.
> >
> > I think some of the feeling expressed in earlier posts that high level
> > terms (such as set) can be ported across theories with contradictory
> > axioms arise from (mistakenly) assuming they have simply portable
> > intended interpretations.
> > That does not mean that other terms are not simply portable or that we
> > do not need to work with intended interpretations. Indeed, given that
> > the practical value of ontologies arises from the intended
> > interpretations, in many situations when producing ontologies these
> > may be key and the formal semantics merely a supporting mechanism.
> >
> > Regards,
> > Chris
> >
>
>
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