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Re: [ontolog-forum] Semantic Systems

To: "[ontolog-forum]" <ontolog-forum@xxxxxxxxxxxxxxxx>
From: "John F. Sowa" <sowa@xxxxxxxxxxx>
Date: Mon, 29 Jun 2009 02:22:49 -0400
Message-id: <4A485DB9.3050400@xxxxxxxxxxx>
Rich and Rob,    (01)

JFS>> Please give me any simple observation statement (i.e., one
 >> that you experienced *directly* without any intervening analysis).
 >> My claim is that any simple observation statement can be translated
 >> to FOL with only two logical operators:  existence and conjunction.    (02)

RC> I observe Paul going to the water fountain.  Later, I observe Wanda
 > going to the same water fountain.  Since both occur in one work day,
 > I consider that one observation for today.    (03)

By "observation" statement, I meant the kinds of statements that
scientists would use in taking notes about what happens in the course
of an experiment.  They would note what happens at a much finer
granularity than one day.  Linguists would typically take notes
at the level of a single verb.  If you need two verbs to describe
something, that means you are making two different observations.    (04)

I'm sure that during that work day you made millions of observations
and even more millions of inferences, generalizations, and guesses
about them.    (05)

In any case, the only logical operators you need for talking about
Paul and Wanda in the above example are existence and conjunction.
You would also need an ontology for time in order to represent
"and then" or "and later".  But you don't need more logical operators.    (06)

RA> How is "one work day" conceptually different from "one lifetime"?    (07)

That is an important point.  For any kind of empirical study, there
is a typical granularity for the kinds of phenomena you're studying.
If you're talking about geological developments, your time step
may be thousands of years.  If you're talking about computers,
you may have a time step that varies from milliseconds (for a disk)
down to picoseconds (for the switching speed of a transistor).    (08)

But whatever the subject matter, you would typically choose a
time step in which there is only one event of interest to describe
in that step -- which is analogous to the "snap" of a snapshot.    (09)

RC> The meaning of the word "same" is critical here;
 > why should I think of that as
 > (And  ('goto 'Paul  'Water_Fountain)
 >      ('goto 'Wanda 'Water_Fountain))
 > instead of
 > (Or   ('goto 'Paul  'Water_Fountain)
 >      ('goto 'Wanda 'Water_Fountain))    (010)

You answered your question in the opening statement above.
You saw both of them going to the water fountain.  So your
normal operator is 'and'.  You would only use 'or' if you
weren't sure which one went -- i.e., it was an inference,
not an observation.    (011)

John    (012)

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