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Re: Meaning

From: Stanislaw Ambroszkiewicz <sambrosz@ipipan.waw.pl>
Date: Tue, 10 Jun 2003 20:24:50 +0200 (CEST)
Message-Id: <200306101824.h5AIOor01795@ns.ipipan.waw.pl>
To: drew.mcdermott@yale.edu
Cc: www-ws@w3.org, sambrosz@ipipan.waw.pl

Drew McDermott <drew.mcdermott@yale.edu>

Nice to meet you again on the list. 
  >  If "owns" really has the meaning it has in natural 
  >  language, then X already knows the meaning before he 
  >  starts dabbling in protocols and plans. He or the 
  >  committee can issue information about how the word
  >  translates into different natural languages, 
  >  clarifications of important borderline cases, and so forth.

In order to have nothing to do with natural language and 
its meaning, let me translate the story into the world of robots. 
Robot X (being at initial situation sIn) performed action A 
and then perceived (via its sensor, say a camera) the situation 
sOut. Situations sIn and sOut are images represented 
as arrays of pixels in the robot memory. X had a goal to 
achieve, say G, represented as a collection of situation. 

Suppose that the robot had a built-in routine for performing 
data abstraction on the basis of its experience.  
For simplicity, assume that the actions have deterministic 
effects. After performing the action A several times at 
different initial situations, the robot was able to compute 
a common pattern P for the initial situations that lead 
to G after performing the action A by X. 
The pattern may be represented as the string P(?sIn, X, A) 
describing what initial situation ?sInthe lead to the 
effect G after performing action A by robot X. 

Then, the robot can also abstract from A and from X. 
That is, the robot can compute a class of actions that 
once performed lead to the same goal, and so on. 

If there is a common syntax where the pattern P can be 
expressed as a formula, the robot can publish it and speak 
to other robots in terms of this relation.  
However, what about the meaning of P(?sIn, ?x, ?a) ?
How can the meaning of this formula be published? 
  >  What's puzzling about the story you're telling is 
  >  that it's trying to solve a problem we shouldn't be 
  >  trying to solve: The problem of how words get their 
  >  meanings and what we mean by the "meaning of a word."
  >  As I argued before, we can formalize protocols and 
  >  their effects using predicates derived from natural 
  >  language, without thereby incurring an
  >  obligation to explain natural language.
One solution: Define an ontology (in PDDL, or even in OPT), 
i.e. a formal language for this particular domain and 
add axioms that constrain the meaning of P. 
   From: Drew McDermott, Wed, May 21 2003 Subject: Meaning: 
     "... The formal specification answers essentially all
     questions about the meanings. ... "

Where is the meaning in a formal theory? 
It is only a syntax, i.e., a naming convention and some 
rules how to transform one string onto another. 
You may say that, according to Alfred Tarski, a formal 
semantics can be constructed for this theory. But this 
semantics is only a translation from one formal theory into 
another one. 

According to another Polish logician, Jerzy Los, 
meaning of a language comes from describing decision making 
and action executions that correspond to that decisions. 
Hence, a formal language is necessary, however its meaning 
should be related primary to the action executions rather 
than to axioms. However, axioms are important; it is much 
more easy to operate on axioms using formal reasoning 
techniques, than to operate on the original meaning. 
Nevertheless, the reference to the original meaning should 
be of some importance especially in the case of so called 
machine readable semantics in an open and heterogeneous 
environment, e.g., the Web. 

Why shouldn't we even be trying to solve the problem of 
how words get their meanings? 
It is my job (as a researcher) to try!
  >  You're right that there won't be one committee that 
  >  decides everything, but there might be lots of committees, 
  >  each of which standardizes the vocabulary in a particular area.  
  >  The trick is to make sure everyone agrees on which committee 
  >  is deciding what.  I don't think that's so hard in a 
  >  heterogeneous distributed environment; sometimes this 
  >  planet seems like a small town, where everyone knows who
  >  is interested in what.

"The trick is to make sure everyone agrees on ... " 
It isn't a trick but it is the problem how to make such 
agreement possible. It is easy, although not completely 
clear how it is done, in the case of natural language. 
However, the problem is how to automate the process of 
reaching agreement for an open language used not only 
by humans but also by applications (web services, agents, etc.).
There must a freedom in the style popularized 
by T. Berners-Lee, i.e., any one can publish an 
ontology (concept) he / she would like to. It is another 
case if this concept will be used and became ubiquitous. 
So that the crucial point here is that only the concepts 
that are useful and became ubiquitous are included to 
standard vocabulary. It is not important whether they 
come from IBM, Microsoft, W3C (although it is much more 
easy for them to force the so called standards) 
as well as from a rustic guy from Poland like me. 
The only criterion should be usefulness and ubiquity. 

The bottom line is the following. 
Since we are talking about machine readable semantics, 
there must be a common infrastructure for realizing it. 
Undoubtedly an important part of the infrastructure is 
open and simple language for describing the domain 
of web services as well as for communication between agents. 
The language will be dynamicaly developed, and in a sense 
it will create the world of web services. 

-- Stanislaw Ambroszkiewicz
Received on Tuesday, 10 June 2003 14:24:55 UTC

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