Chris --
Thanks for taking the time to discuss this.
You wrote (below)
I'm not sure what you mean by "RDB" in this context -- relational
database? I don't get the connection there with semantics. Do you
have the idea of a relational datamodel in mind here? I would agree
that is a kind of semantics, insofar as it specifies logical properties
of, and relations among, a set of pertinent classes. But XML is a
language for markup specification, and RDF is just itself an
(expressively rather weak) language. It's hard for me to think of any
sense in which these count as semantics.
I agree that the notion that these things have semantics is rather
weak. I'm just going along with the Semantic Web folks' usage -- they
attach the "semantic" label to data that has a schema, or that is
interleaved with metadata as in XML or RDF.
Ok, one uses the model theory (of which fixpoint theory is a
species)
to define the notion of validity with respect to which one implements a
reasoning engine. Is that what you mean?
Yes, exactly.
Absent that, one gets into problems where a collection of clauses
yields different conclusions depending on implementation details of the
engine that executes them. (This is particularly tricky when dealing
with closed world, non-monotonic negation as is the usage over
commercial databases.) So, it seems reasonable to say that the model
theory assigns a clear declarative meaning to any collection of
clauses, and that an engine is correct if it faithfully
reproduces that meaning.
I appreciate what you
are doing, but it's hard for me to see that you've done anything more
(or less) than introduce a sort of structured English for queries
rather than a more mathematical notation -- an idea that has of course
been around for a long time. But all this approach does is give logic
a prettier face. I don't want to denigrate that -- I think that is a
very good thing to do. But I think your packaging suggests you've done
something more than that, that it captures "real world" semantics more
effectively than more formal notations.
I guess I'd defend the "real world semantics" description by noting
that others have described the shortcomings of using only formal
notations for real world tasks, see e.g. slides 21 and 22 of
www.reengineeringllc.com/Internet_Business_Logic_e-Government_Presentation.pdf
.
Actually, although the support for English in the system is technically
rather simple, the approach means that the executable English that one
can usefully write is essentially unstructured.
The vocabulary is open, and so to a large extent is the
syntax. This, of course, is puzzling if one is used to classical
dictionary-grammar approaches. There is a trade off involved -- if an
author wants the system to regard two sentences as having the same
meaning, he must write that down explicitly. An upside is that the
English meanings are precise.
I understand that that some of the above will be counter-intuitive to
many people. However, the system is online**, and you can use a
browser to view, run and change the examples provided. List folks are
cordially invited to write and run their own examples. Thanks in
advance for taking some time to do this, and for further comments.
Adrian
Walker
--
**Internet Business Logic (R)
Executable open vocabulary English
Online at www.reengineeringllc.com
Shared use is free
Reengineering, PO Box 1412, Bristol, CT 06011-1412, USA
Phone 860 583 9677
Mobile 860 830 2085
Fax 860 314 1029
Christopher Menzel wrote:
On Apr 12, 2006, at 10:00 AM, Internet Business Logic wrote:
Hi Patrick --
...
You wrote....
If your argument that widespread use of formal ontologies or
other methods will require better interfaces for the average user, I
don't think you will find much disagreement on this list or elsewhere.
But, and it is an important but, unless the underlying principles which
are used by such an interface can be specified and discussed with
precision, then the results of any interface are not going to be
particularly useful.
The key here is that if one is doing "semantics" in the real world, it
is no longer enough to produce a formal notation and hope that someone
will produce a non-geek-human understandable user interface to it.
That approach leaves open likely semantic disconnects between the human
meaning and the system meaning.
What we have done is essentially to integrate 3 kinds of
semantics in one design and system [1]:
- Semantics1 is "Data Semantics". as in RDB, XML or RDF
I'm not sure what you mean by "RDB" in this context -- relational
database? I don't get the connection there with semantics. Do you
have the idea of a relational datamodel in mind here? I would agree
that is a kind of semantics, insofar as it specifies logical properties
of, and relations among, a set of pertinent classes. But XML is a
language for markup specification, and RDF is just itself an
(expressively rather weak) language. It's hard for me to think of any
sense in which these count as semantics.
- Semantics2 specifies what a reasoning engine should do (in
our case via a model- and fixpoint-theory [2])
Ok, one uses the model theory (of which fixpoint theory is a species)
to define the notion of validity with respect to which one implements a
reasoning engine. Is that what you mean?
- Semantics3 concerns the Application Semantics in the meaning
of English concepts at the author- and user-interface.
In the system, the link between Semantics3 and Semantics2 is of course
automatic, and two way. You can verify that it works by using a
browser to view, run and change the examples at [3], and by writing and
running your own examples.
In principle, the way that this works is by automatically mapping
English sentences, with place holders (variables) for values, to- and
from- predicates. There are some complexities our implementation of
this, but it is conceptually quite simple. It is in no way a
contribution to research in natural language processing [4], just a
minimalist and robust way of grounding Semantics 1 and 2 out to
something meaningful to nontechnical humans (Semantics3).
I appreciate what you are doing, but it's hard for me to see that
you've done anything more (or less) than introduce a sort of structured
English for queries rather than a more mathematical notation -- an idea
that has of course been around for a long time. But all this approach
does is give logic a prettier face. I don't want to denigrate that --
I think that is a very good thing to do. But I think your packaging
suggests you've done something more than that, that it captures "real
world" semantics more effectively than more formal notations.
Sure, we all know and love our succinct
logic and programming notations, but they were invented before Von
Neumann, and they deliberately leave out the pragmatics of natural
language.
I am not sure what you mean by the "pragmatics of natural language?"
Granted that logics and programming notations are more limited than
natural languages but then they never pretended to be natural
languages.
BTW, historically speaking, there have been a number of logics
"invented" post von Neumann.
Moreover, there weren't any programming languages at all invented
before von Neumann. Indeed, von Neumann himself only stated the basic
concepts of a programming language in the abstract.
Regards,
-chris
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