John, (01)
I distinguish between two kinds of ontologies: Language defining ontologies and
general ontologies that express knowledge in
general. The first category only defines concepts and specifies knowledge about
how a (formal) language is defined to express
relations between the defined concepts. That is where Universal Basic Semantic
Structures are required.
A general ontology is by nature expressed in a general formal language, such as
Formal English. Such a formal language should be
defined by a 'general language defining ontology'. The latter ontology should
contain only definitions (expressions of facts that
are by definition the case), whereas in a general ontology there is also room
for the expression of possibilities and options. (02)
> -----Oorspronkelijk bericht-----
> Van: ontolog-forum-bounces@xxxxxxxxxxxxxxxx
>[mailto:ontolog-forum-bounces@xxxxxxxxxxxxxxxx] Namens
> John F Sowa
> Verzonden: woensdag 26 september 2012 22:01
> Aan: ontolog-forum@xxxxxxxxxxxxxxxx
> Onderwerp: Re: [ontolog-forum] Universal Basic Semantic Structures
>
> Andries, Doug, William, and Rich,
>
> Any general purpose ontology has to be useful for the full range
> of applications for computer systems. That means it must be span
> the range of semantics from informal language to every branch of
> science, technology, business, law, medicine, and the arts. (03)
[AvR] That sound trivial. Although the 'semantics of informal language' might
be ambiguous. And such an general purpose ontology
will never be complete, in the sense that there will always be subtypes missing. (04)
>
> The most successful approaches span that range by using an
> underspecified upper level ontology with very few axioms
> and with specialized microtheories for various kinds of
> applications. (05)
[AvR] Instead of 'underspecified' I would say that successful approaches should
not include 'unnecessary constrained' upper level
concept definitions. But I expect that you mean the same.
And for the lower levels and application domains holds that domain ontologies
(mainly) relate subtype concepts in one or some
branches of a taxonomy, which concepts are application domain specific. I
expect that is what you mean with 'microtheories'.
>
> AvR
> > Design of buildings usually starts with the design of spaces
> > (rooms etc.), then the walls are added. I consider the spaces
> > to be components of the building (not as an assembly, but
> > as a component).
>
> That's a useful view by architects, and it should be supported.
> But geometry is the general theory of space, independent of any
> content or physical boundaries. The architects who design
> buildings and the contractors who build them use geometry that
> is consistent with the mathematicians and physicists.
>
> AvR
> > I question whether a physical area is by definition two dimensional.
> > Mathematical area's are two dimensional. But two dimensional area's
> > in physical reality seem to be abstractions.
>
> Of course it's an abstraction. Physicists, engineers, and building
> contractors are well aware of the approximations needed in their work.
> But they use classical Euclidean geometry to measure anything on planet
> earth that's not moving close to the speed of light. And they have
> established "best practices" for dealing with errors in measurement.
>
[AvR] We should make a clear distinction between physics and mathematics
(geometry). Concepts such as physical space and shape are
from another domain than mathematical space and geometric functions that can be
used to model aspects of the physical world in
abstract terms.
That is why I stated that physical areas and surfaces are not two dimensional.
Two dimensional things only appear in abstract,
idealized mathematical models. (06)
> AvR
> > This is related to the concept of 'surface'. A surface can have a roughness,
> > a color, a hardness, a temperature, a strength, etc. I think that it can't
> > have such properties when it would be only two dimensional.
>
> Yes. But countries and school districts specify their boundaries by
> using classical Euclidean geometry in polar coordinates (latitude and
> longitude). They don't specify roughness or depth until a specific
> application needs to address those issues. Then they switch to an
> appropriate microtheory that deals with them.
>
[AvR] The boundary between physical and mathematics is in relations, which we
usually call scales (or units of measures). They map
physical properties to numbers (or mathematical spaces), using scales.
When such properties are modeled in mathematical terms, then the proper
sections of the language ontology are used. I.e. properties,
scales and numbers. (07)
> > In some cases (e.g. mines, reservoirs) the subdivision of the earth
> > requires an explicit third dimension.
>
> Yes. But the specification of the region begins with the latitude
> and longitude. The depth depends on the application. Engineers
> that specialize in mining or reservoirs will use very different
> microtheories for dealing with the depth. (08)
[AvR] The only 'microtheory' that reservoir engineers use for measuring depth
is that they use another reference for measurement
than when we measure other distances. That might introduce a few additional
concepts, but for the definition of the Formal Language
that makes little difference and does not justify taking about a separate
theory. (Apart from the fact that reservoir engineering
applies detailed theories)
>
> > And some, such as lakes and mountains, don't need a role.
>
> Nature is independent of the way we think or talk about it. But
> people choose different ways of classifying natural phenomena for
> different purposes.
>
> The reasons for a classification must be recognized by an ontology.
> And experts in different fields have different ways of classifying
> the same features. Consider a park ranger, a mountain climber,
> a lumberjack, a mining engineer, or a real-estate developer.
> They use very different microtheories.
>
> DF
> > I find 314 specializations of #$touches...
>
> Those and other examples from OpenCyc are important.
>
> DF
> > Cyc made the distinction of treating geopolitical entities from
> > geographical regions in 1998. One could use a context in which
> > the geopolitical entity was an agent, or one in which it was
> > also a piece of land...
> >
> > I urge people who want to develop ontologies of common things to
> > first check what OpenCyc has. It can save a lot of reinventing of
> > complex wheels. Cyc is certainly far from perfect and has huge
> > holes, but with hundreds of staff years being put into a publicly
> > available ontology, many parts of which are very carefully considered,
> > it can be used to speed up such ontology development projects.
>
> I agree. Nothing is perfect, but the Cyc developers invested
> a thousand person-years of work by 2010. Anybody who develops
> a general purpose ontology should study the OpenCyc ontology
> instead of re-inventing the wheel.
>
> WF
> > Try to imagine a thing you could not classify at all. I just can't.
>
> That's true. Every act of perception classifies sensory input
> in some way, and imagination builds on the memories of earlier
> perceptions.
>
> RC
> > no two people use exactly the same ontology, which is one of those
> > things that make interpersonal communications so very faulty.
>
> True. But people are much more flexible than computers. The major
> challenge is to design more flexible computer systems. We're not
> going to achieve that if we force them to use a rigid, monolithic
> classification that cannot grow and adapt.
>
> John
>
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