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Re: [ontolog-forum] Reality and semantics. [Was: Thing and Class]

To: "[ontolog-forum] " <ontolog-forum@xxxxxxxxxxxxxxxx>
From: Pat Hayes <phayes@xxxxxxx>
Date: Wed, 17 Sep 2008 01:29:56 -0500
Message-id: <4121B734-4EDB-43B1-A919-2D9E3297F3CA@xxxxxxx>

On Sep 16, 2008, at 7:30 PM, John F. Sowa wrote:

Pat and Chris,

JFS>>> A Tarski-style model is a set of entities and a set of
relations among those entities.  Those entities and relations are
*approximate* representations of aspects of the world according to
some ontology.

CM>> Sure.  Every model leaves out information that is found in the
piece of the world that the model represents.

PH> Represents? Ouch. If there is a 'represents' relationship between
models and reality, then all our axiomatic ontologies must be given
a two-stage semantics, in which model theory describes the first
stage of interpretation, yielding a new kind of 'representation'
which then needs another, presumably different, semantic theory to
relate it to actuality.

Welcome to reality.  As George Box said and I quoted in my previous
note, "All models are wrong, but some are useful."

Its not reality. In fact, we all manage extremely well with a single-layered semantics called model theory. This two-level idea is a chimera, and an intellectual dead end.  You have argued for the idea, but do you have even an outline or a sketch of what the second, model-to-reality, semantic theory looks like? In order to give it, you need to somehow describe reality mathematically. In full generality. OK, I'm all ears. 

PH> Not only has this project never been undertaken to completion,
I don't think its needed.

That is why 20th century analytic philosophy has trivialized the
subject to the point where the total number of bookshelves devoted
to philosophy in a large Barnes & Noble store is equal to the
number devoted to Sudoku puzzles.

This comment is completely off the wall. 

CM> ... it might look like Pat and I disagree about this, but I
don't think we do.  I believe that all Pat is saying is that
Tarski-style models can be constructed out of real world objects
and (extensions of) real world relations in such a way that, as
far as they go, they directly represent reality as it is; they
don't just contain "formal surrogates" of real world objects or
the like (as I recall John putting it once).

I'll agree that this statement is more acceptable than Pat's way
of stating it.  But it is still an apology for the status quo.

Apology? Why do you think  the status quo needs apologizing for? Im very happy with the semantic status quo. It is a powerful, mature subject with a long and successful track record, and it continues to grow and strengthen. It is the foundation of ontology engineering, for a start, as well as such topics as decideable logics (such as DLs). 

CM> But, given that a Tarski-style model (in contemporary model
theory) is *literally* an n-tuple of a certain sort, I think
Pat would agree that they are not *literally* parts of (physical)
reality but rather structurally very accurate representations
of reality.

I certainly won't accept the phrase 'very accurate'.  Just consider
your examples of "people, tables, and cabbages".  How are you going
to form n-tuples of such things when you can't even state clear
criteria for identifying individuals of those types?

Easily. You don't NEED to give such individuation criteria in order to talk clearly and precisely about n-tuples. This is a basic point in mathematical philosophy that you seem to have a recurrent blind spot about. But in any case, its fairly easy to state individuation criteria for people, tables and cabbages: you can do it using spatiotemporal contiguity in all three cases. 

 And those are
the simplest "real world" examples you can find.  Everything else
is immensely more difficult.

Well, in fact it often isn't all that difficult, which is why ontology-writing is possible at all. 

Whenever I raise issues like this, people try to hush me up with
complaints like "You're confusing ontology, epistemology, and logic."
But that distinction, which might be acceptable if you're writing an
academic paper,

It is helpful if you are trying to think clearly.  Getting these muddled is just as poisonous when building working systems as it is everywhere else. And  I reject the anti-intellectual, or perhaps it is simply anti-academic, implications of your implied contrast here. By and large, its the people who build the best robots or the best NL-comprehension software who also tend to write the best academic papers. 

doesn't help anyone design programs that understand
language or guide robots down a highway or across a field.

On the contrary, it does. But in any case, building ontologies and building robots are two different activities. And understanding natural language is yet a third.

PH> I will just note that almost all writers on formal semantics
(including Quine, Russell and Carnap, and indeed every written
authority I have ever consulted on the topic) disagrees with you.

If you add Frege to that list, you have a quartet of brilliant
logicians and philosophers who have helped us all hone our
logical skills.  But their attitudes toward language, logic,
and their interrelationships have polished formal semantics to
an elegant system that ignores problems instead of solving them.

This is such rubbish that I won't even try to sketch a response. Which *semantic* problems are being ignored? If you are referring to understanding natural language or speech, I agree there is far more to that then is covered by logical semantic theory. In fact I would go so far as to say that the whole idea of treating NL as similar to a logic, which reached an apogee with Montague, is now dead in the water. But that is NL comprehension, and this forum about ontologies. Different topics. 

The alternative I would suggest is what I mentioned in my
previous note to another thread (copy below).  I believe that
philosophers would have made far more useful contributions to
linguistics and AI if they had given equal attention to those
other three.  As it is, the failures of many formal approaches
have caused many people to reject logic itself as irrelevant.

There is no point in continuing this discussion, which has descended into uninformed rhetoric. Please document all these 'failures' of the approach that you yourself adopt in almost all your own work, before continuing with such meaningless jibes.

BTW, none of this has anything to do with the Kripke/Dunn issue. 


PS.  I agree with Carnap (see below). I've never found poetry to be anything other than badly constructed language, much of it unreadable, almost none of it actually worth reading. Give me a cubist painting any day.


RF>> I don't think this indicates an "End of Theory" so much as
"the birth of the theory that there can be lots more theories
buried in a set of data than we've ever imagined we needed to
look for before."

My only quarrel with that statement is over the word 'birth'.
Some logicians I admire (among them, Peirce, Whitehead, and the
later Wittgenstein) have said or implied something similar.  In
fact they would agree that the number of possible theories and
even theories that are reasonably accurate for useful applications
is either infinite or far beyond our practical ability to count.

At the end of this note are some of my favorite quotations from
Whitehead, Peirce, and Robert Frost.  If you do a global change
of Frost's word 'poem' to 'theory', you would get a statement
that Peirce, Whitehead, and Wittgenstein would have agreed with.

Actually, they would have agreed with Robert Frost's original
with the word 'poetry' in it.  That attitude should be contrasted
with Rudolf Carnap, whose favorite phrase for denouncing some
idea was "That's poetry!"


Alfred North Whitehead:

    Human knowledge is a process of approximation.  In the focus of
    experience, there is comparative clarity.  But the discrimination
    of this clarity leads into the penumbral background.  There are
    always questions left over.  The problem is to discriminate exactly
    what we know vaguely.

Charles Sanders Peirce:

    It is easy to speak with precision upon a general theme.  Only,
    one must commonly surrender all ambition to be certain.  It is
    equally easy to be certain.  One has only to be sufficiently vague.
    It is not so difficult to be pretty precise and fairly certain at
    once about a very narrow subject.

Robert Frost:

    I've often said that every poem solves something for me in life.
    I go so far as to say that every poem is a momentary stay against
    the confusion of the world....  We rise out of disorder into order.
    And the poems I make are little bits of order.

Alfred North Whitehead:

    We must be systematic, but we should keep our systems open.

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