This is the way I have started to approach context; Contextual statements
can be made, for example, OWL-Full by allowing statements about statements.
Given a class of context and an instance "car" we would have statements
about "steering wheel". "steering wheel" and associated axioms are "in the
context of" "car" (none exclusively). The same relation would hold for
statements in the context of "Cyc" (Or some Cyc microtheory). A computation
done outside of the context of Cyc would then not include those statements.
In the problems I was facing in merging forms of expression for
architectures as well as for expressing the often conflicting architectures
them selves (and reasoning about them), context seems necessary. It also
seems necessary for extremely common concepts. It would also seem a way to
get around the inevitable "single truth" conflicts and arguments that arise
when all things are absolutely true all the time.
Namespaces do provide a form of context for the terms of our concepts but
are somewhat "flat" for expressing the intersecting context of normal
statements.
So yes, I would consider what the organizing principle is for ontological
statements in unifying framework to allow for neutrality as well as for
suitable expressiveness. (01)
-Cory
-----Original Message-----
From: ontac-forum-bounces@xxxxxxxxxxxxxx
[mailto:ontac-forum-bounces@xxxxxxxxxxxxxx] On Behalf Of Barry Smith
Sent: Monday, November 28, 2005 1:42 AM
To: ONTAC-WG General Discussion
Subject: RE: [ontac-forum] Neutrality Principle (02)
Cory suggests that we introduce a new layer to our ontology work: the
layer of context. (This is analogous to the Semantic Web idea that we
separate out ontologies into walled-off zones called namespaces,
though seemingly more difficult, since namespaces are just a matter
of syntax; Cory's contexts seem to be something more complicated.) (03)
Three problems then arise: (04)
1. in addition to building the ontology (or ontologies), which is
hard, we would need to build also a theory (or theories) of contexts
on a level on top of that, which is even harder (05)
2. even if we have a good theory of contexts, and even if we can fit
all our ontologies neatly into contexts (perhaps into different
contexts at different times), we would still need to find a way of
unifying the ontologies themselves, at the ground level, in ways
which will make them interoperable -- but this means finding out what
stands up, ontologically, independently of context (06)
3. would we then need also a second-level theory of the context(s) in
which the theory of contexts itself is formulated/expressed? and a
third-level theory for the contexts in which this second level theory
is formulated? (07)
Certainly, the ontology of ordinary speech acts is itself a good
candidate (low-hanging fruit) for what might be included in a
ground-level ontology; but not, please, an ontology of those speech
acts which are used by a certain very small and very specialized
community when it talks about ontologies.
BS (08)
At 07:12 AM 11/28/2005, you wrote:
>John,
>Ok, now imagine a small hour glass spinning over my head, absorbing all the
>references on this thread takes a while!
>
>In the mean time, there are two points where we were not communicating.
The
>"modular" I was thinking of was in terms of a family of related Ontologies,
>or perhaps micro-theories (I will switch to that phrase). In the framework
>I was imagining, the context represented by the micro theory parameterizes
>the axioms. I think I understand your use of "module" to be individual
>"engines", each with a small ontology, interacting with others -
essentially
>an agent like system.
>
>Point 2; there is an ontology of speech acts (which is quite interesting)
>but there are also the speech acts about the Ontologies (or micro theories)
>themselves - which may provide some of the parameters for computation based
>on context. To use your example, controlling a bus, airplane, mars rover
>provide a situational context for the axioms specific to that vehicle. The
>speech act about the set of Ontologies also provides context and thereby
>selects what axioms are applicable.
>
>If our UF provided for parameterizing micro-theories by context it would
>then be able to admit seemingly incompatible macro-theories.
>
>I understand the complexities that such parameterization causes for
engines,
>but perhaps we can find a tractable subset of unconstrained model
>non-monotonic logics that would suffice. Something like applying the
>parameterization prior to the inference?
>
>-Cory
>
>Ps; An odd example of the speech act mess; Lets say we are charged with
>specifying a "current state" "future state" architecture, each of course
has
>the appropriate speech act. <architecture 1> is stated to represent the
>current enterprise. <architecture 2> is stated to be a specification of
how
>the enterprise will operate at point in time "C". Now add to this a
>future-state architecture done five years ago - this does not, of course,
>correspond to how the future actually worked out. <Architecture C> is
>stated to be an unrealized plan for timeframe B done in timeframe A.
Speech
>act E - what is the difference between these architectures?
>
>-----Original Message-----
>From: ontac-forum-bounces@xxxxxxxxxxxxxx
>[mailto:ontac-forum-bounces@xxxxxxxxxxxxxx] On Behalf Of John F. Sowa
>Sent: Sunday, November 27, 2005 11:45 PM
>To: ONTAC-WG General Discussion
>Subject: Re: [ontac-forum] Neutrality Principle
>
>Cory,
>
>Before getting into the details of your note, I'd
>like to emphasize the point that the the idea of
>concentrating on vocabularies for UF and minimizing
>the detailed axioms is only part of the story. I
>definitely do *not* advocate throwing away axioms.
>But I believe that putting them into a single monolithic
>lump is too inflexible. Even Cyc has subdivided the
>axioms in multiple microtheories, but there's more
>structure needed for interactions among modules.
>
> > Similar to your suggestion of modularity, perhaps
> > the common framework is itself modular in such a way
> > that conflict is explicitly allowed for between its
> > modules. There is a tendency to think of these systems
> > monolithic statements of Truth, and while some have had
> > that intent, it may not be necessary for our purposes.
>
>Yes, I very strongly agree.
>
> > If we instead think of each of these ontological modules
> > as "speech act"(s), an assertion by an individual, group
> > or authority at a particular time. We can have a framework
> > for dealing with a system of these modules that may or may
> > not be in conflict.
>
>Yes. Inferencing and information flow are related, but
>they have different requirements. In communication, the
>most prominent features are the speech acts and vocabulary.
>I published an article that emphasized speech acts and
>their relationship to modularity:
>
> http://www.jfsowa.com/pubs/arch.htm
> Architectures for Intelligent Systems
>
>This article was strongly influenced by John McCarthy's
>Elephant 2000 language, which is based on speech acts.
>The article introduces the Flexible Modular Framework (FMF),
>in which interacting modules pass messages among themselves,
>each one with a tag that indicates the speech act. For
>McCarthy's original paper on Elephant, see
>
> http://www-formal.stanford.edu/jmc/elephant/elephant.html
> Elephant 2000: A Programming Language Based on Speech Acts
>
>A quotation from that article: "Human speech acts involve
>intelligence. Elephant 2000 is on the borderline of AI, but the
>article emphasizes Elephant usages that do not require AI."
>
>My colleague Arun Majumdar implemented a version of the FMF
>while he was living in Palo Alto and had a number of discussions
>with McCarthy about Elephant, speech acts, and related issues
>of logic and reasoning.
>
> > The speech act asserting a set of statements forms one dimension
> > of context for those statements. A set of statements is valid
> > within a context. There are, of course, other forms of context
> > such as authorities/political, physical or situational. All can
> > govern how and when statements within that context are to be treated.
>
>The word "context" has many senses. The speech act indicates the
>purpose of the communication: tell, ask, command, promise, commit,
>authorize, deny, etc. The basic three -- tell, ask, command --
>have been implemented in computer languages for years, but the
>others are important for on-line business transactions.
>
>Another sense of context involves the subject matter, which brings
>in specialized axioms or programs that deal with the information
>content of the message. The kind of axioms required depend on
>both the subject matter and the speech act. One of the basic
>principles of the FMF is that a module should be able to determine
>quickly whether it is capable of handling a message, and if not,
>where to send it.
>
> > Using something like wordnet makes a lot of sense for informal
> > (but still useful) connections, but I don't see how it works
> > for formal ones.
>
>You can think of the modules as having different levels of expertise.
>Some modules may be highly specialized, and others could behave
>like a receptionist, who isn't an expert in anything, but who
>knows enough about the subject to route a message to another module
>that can handle it. The FMF also supports various blackboards, on
>which a module can post messages that are retrieved associatively
>by other modules that are looking for things to do.
>
>Inside a module, there might be a highly specialized and optimized
>program, or there could be an inference engine that does reasoning,
>which could transform a message and generate new messages for other
>modules. So even for the same subject domain, different modules
>could have different axioms (or compiled programs) that do different
>things.
>
>This approach does not rule out monolithic systems, if they are
>needed -- you could take all of Cyc, put a wrapper around it,
>and it would look like a module. But you could also split the
>microtheories or other axioms into different modules that would
>deal with specialized subjects in specialized ways.
>
> > Given such contextual modules you can determine what modules are
> > in conflict with others, and perhaps provide logic to reduce or
> > eliminate the root causes. (For example, the assumption that time
> > is the same for all participants - which works just fine in the
> > context of earth systems but not in the context of space flight).
>
>That's an example where different modules could use the same
>vocabulary about space and time, but different sets of axioms
>for reasoning about them. Even for travel, you need different
>axioms and ways of thinking about driving a bus, guiding a
>Martian rover, sailing a ship, running a railroad, or planning
>a space mission. One set of axioms definitely does not fit
>all applications, even when there is a lot of common vocabulary.
>
> > Almost all human abstractions seem to be highly contextual, yet
> > most logics don't have the mechanisms to deal with it due to
> > the monotonic restrictions.
>
>I certainly agree. OWL, for example, is an extremely limited logic,
>which doesn't even support full FOL. It might be adequate to handle
>the limited kinds of axioms needed for WordNet, but certainly not
>for nonmonotonic, modal, higher-order logics that interface with
>programs that do specialized computation.
>
> > One of the goals for this is to have a wider net for capturing
> > knowledge, much of which is expressed in ways that are imprecise,
> > lacking in detail and contradictory.
>
>Knowledge acquisition, design, problem specification, and many
>related issues involve very different issues that are orthogonal
>to the communication/inferencing dichotomy. That is one more
>reason for breaking up the system into multiple interacting modules,
>each with different kinds and levels of expertise.
>
> > So, in summary, can we find a way to "admit all" instead of
> > least-common denominator by applying context to statements as
> > speech acts from various communities or authorities?
>
>I believe that it's possible, and I also believe that a monolith
>is not sufficiently flexible to handle the job. Modules, along
>the lines we are discussing are a prerequisite, but there's still
>a lot of R & D to do in order to determine the best way to divide
>up various tasks among interacting modules.
>
>John
>
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