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Re: [ontolog-forum] Reality and semantics.

To: "[ontolog-forum] " <ontolog-forum@xxxxxxxxxxxxxxxx>
From: Pat Hayes <phayes@xxxxxxx>
Date: Fri, 19 Sep 2008 19:14:47 -0500
Message-id: <630D47AA-62E3-4C13-B76F-4176A6D863A9@xxxxxxx>

On Sep 19, 2008, at 3:02 PM, Len Yabloko wrote:


On Sep 19, 2008, at 10:17 AM, Len Yabloko wrote:

Pat,

I was not arguing that the model does not represent anything real or  
that reality somehow does not matter. I don't suffer from  
positivism. But at the same time I recognize that reality can not be  
comprehended mathematically or otherwise. It is you who seem to  
insist that complete mathematical comprehension is required for  
progress.

Not at all. I never said anything about being complete. Of course all  
descriptions are incomplete. But they can still be true. And the role  
of semantics is to account for this, analyze what it means, etc..

Then may be I misunderstood where your and Johns's positions differ. I admit -it is hard for me to follow, but I do "sense" the relevance of it. And so I would like to understand why you objected to 'represent' being the relation between the model to the actuality.

We need to be careful about what 'model' means. Unfortunately its use in 'model theory' is almost the exact opposite of its intuitive normal meaning, which is why this is more than mere pedantry.  

My point (I just sent off a long exposition to the thread) was only that logical semantics relates a logical representation to reality, not to a representation or "model" (intuitive sense, as in 'model airplane') or description of reality.  John's position is that this never happens, that logical semantics cannot possibly relate logic to reality, only to an intermediate abstraction which then must itself be related to reality by some other means, hence the 'two-stage' terminology.

You seem to be implying that while you can represent knowledge using model-theoretic semantics - the same can not be said about actuality.

Um, not quite. Knowledge is represented using logic (in the case under discussion, i.e. a logic-based ontology), and the semantics is an account of how this representation relates to the reality it describes (more precisely, to some reality it could be describing.)

To me the word 'represents' means the same as 'interfaces' - that is serves as a conduit for interaction and (limited) comprehension.

Interesting. Im not sure I follow this, but I think I disagree :-)

BTW, of course reality can be comprehended. We do it all the time. We  
don't ever get complete comprehension, maybe, if that means what I  
suspect you mean by it. But I didn't say anything about being complete  
(in this sense, ie comprehensive, all-knowing).  But its still the  
actual bridge that falls into the river when the cables break, not our  
incomplete comprehension of it.


But what difference does it make for us in general and for your's and John's discussion?

Well, if you had been on the bridge at the time, quite a lot. This isn't meant to be a joke, by the way. I find it hard to understand how anyone can say that reality isn't important, when just about all the things that happen to us happen by virtue of impinging upon reality in one way or another. 

The truth of any statement depends on initial assumptions and inputs obtained from some representation.

No, really. The TRUTH depends on how well the representation corresponds to reality. That is pretty much what truth means, in fact. What you are talking about, I think, is how we come to know things, which indeed does have to do with interfaces and transduction. 

The role of semantics is to make a sound connection from later to former. Moreover, semantics can not be fixed, but must allow for cycles of expansion and compression to accommodate growth and physical limits. Isn't that what you call two-stage semantics?

No, thats not what I mean. In fact I cannot follow this stuff about expansion and compression. 

Pat





Pat





On Sep 18, 2008, at 6:49 PM, Len Yabloko wrote:


On Sep 18, 2008, at 3:21 PM, Ed Barkmeyer wrote:

Chris Menzel wrote:
On Thu, 18 Sep 2008, Ed Barkmeyer wrote:
...
As to the rest of John's posting, I refuse to be drawn into a
discussion of the power of either mathematics or logic.  I am an
engineer.

And you won't discuss it because, as an engineer, and hence as  
one
familiar with bridges, moon shots, computers, the web, and the  
like
that
wouldn't exist but for the power of mathematics and logic, it  
isn't
worth discussing something so obvious?  Right on.

Indeed.  That power is well documented and in evidence.  But  
whether
mathematics can correctly capture "reality", as distinct from how
much
of the derived and quantified property called load it will take to
collapse the bridge, is not my concern.

In brief: omit the scare quotes.  By 'reality' I mean something  
very
mundane. All I mean is that when an engineer does some calculations
and then says "the cables aren't strong enough to support the  
deck",
that she really is talking about the cables and the deck. That is
what
"reality" means in this example: the real, actual stuff that the
engineer is concerned with, the stuff that will collapse into the
river if mistakes are made. She is not talking about a model of the
cables and the deck, or about representations of the cables and the
deck. Who would care if a model or a representation fell into the
river?

Pat


My answer to that last question is: those who leave by that model
and representation do care.

Um... not sure I can parse that. ("leave by that model"?)

Perhaps all they care about is the model, because all they know
about reality is the representation.

Yes, of course. All we every know of reality is encoded in
representations of it: mental representations, many of them. In fact
the prime lesson of current cognitive science seems to be that we are
in a very real sense made of representations, a kind of self-
maintaining self-referential tower of representation. But it doesn't
follow that these representations are not OF REALITY. To think that
because all we have is a representation, that therefore the
representation isn't really OF anything, is a very deep and  
pernicious
fallacy. Representations are useful precisely because they are
representations OF something real. If they were not, they would be no
more use than dreams. When the Verrazano Narrows bridge collapsed, it
was a real bridge that fell, not a model or a representation of a
bridge.

Pat





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