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Re: [ontolog-forum] Current Semantic Web Layer Cake

To: "Gary Berg-Cross" <gary.berg-cross@xxxxxxxx>
Cc: "[ontolog-forum] " <ontolog-forum@xxxxxxxxxxxxxxxx>
From: Pat Hayes <phayes@xxxxxxx>
Date: Thu, 2 Aug 2007 15:34:09 -0500
Message-id: <p06230903c2d7ec91298a@[]>
>It seems to me that the hunch that " my Aunt Jane's positive attitude is
>part of the reason she is a 20-year breast cancer survivor." might have
>something to it, but others might have the hunch that " my car Herbie's
>positive attitude is part of the reason it is a starts for me in the
>I could a surface analysis of this and come up with a possible set of
>car attitudes.  But based on others things that I think I know I'm
>probably not on safe grounds making these" attitudes" a set reflecting
>what's in the physical universe.    (01)

Without wanting to start an(other) endless 
discussion about what is really real, there is a 
point here Id like to straighten out, about sets 
and 'things'. The Tarskian model-theory view of 
the 'universe of discourse' D as being a set, 
does not imply that the things in that set have 
to be physically real. Nor that they are real in 
any other sense, in fact. Nor, on the other hand, 
that they are unreal or merely formal. Real, 
unreal, imaginary, Platonic, abstract or physical 
things can all be things in sets. So the 
distinction you are drawing here between a set of 
attitudes and a set of real physical things, 
while no doubt important for judging the utility 
or accuracy of an ontology, has nothing at all to 
do with model-theoretic semantics, which applies 
to both of these cases in exactly the same way. 
The 'universe of discourse' D is a set of 
entities which are the things the language talks 
about, in effect. Calling this a 'universe' is 
not meant to imply that it is the collection of 
actual things that really do exist in some 
scientific sense. Rather, it is something like 
the universe that one would have to accept as 
real if one were to take the assertions made in 
the language at face value, as themselves 
veridical. If my language talks of attitudes, 
then taken at face value it does indeed require 
that the world it describes contains things 
called 'attitudes'. If the real world cannot 
contain such things, then my language is false of 
it; but it might be true of some possible but 
non-actual world.    (02)

Pat    (03)

>Gary Berg-Cross, Ph.D.
>Spatial Ontology Community of Practice (SOCoP)
>Executive Secretariat
>Semantic Technology
>Suite 350  455 Spring park Place
>Herndon VA  20170
>-----Original Message-----
>From: ontolog-forum-bounces@xxxxxxxxxxxxxxxx
>[mailto:ontolog-forum-bounces@xxxxxxxxxxxxxxxx] On Behalf Of Kathryn
>Blackmond Laskey
>Sent: Thursday, August 02, 2007 1:31 PM
>To: Pat Hayes; Kathryn Blackmond Laskey
>Cc: [ontolog-forum]
>Subject: Re: [ontolog-forum] Current Semantic Web Layer Cake
>>>...my Aunt Jane's positive
>>>attitude is part of the reason she is a 20-year breast cancer
>>>survivor. In order to make sense of that sentence, do I need to
>>>believe there really *is* a set of all possible attitudes, and that
>>>there is a member of this set that really *is* my Aunt Jane's actual
>>... in this case it seems reasonable to take the sentence at face
>>value, at least at first.
>>>That is how I would represent this sentence if I were to construct a
>>>logical theory...The natural way to do this would be to define a
>>>function that maps a person x to the person's attitude Attitude(x).
>>>The domain of the Attitude function is the set of all persons, and
>>>the range is the set of all attitudes.
>>Right. (My only worry here is the possibility that one might have
>>several attitudes simultaneously, but that could be formalized
>And attitudes change over time, and... I wanted to start simple.
>>>I'm willing to accept ... To some degree, we can ascertain whether
>>>a person has a
>>>positive attitude...
>>OK. A quick remark: the 'being able to ascertain' isn't necessary,
>>in order to accept that attitudes exist.
>Of course.
>>>   But I'm not at all sure I agree that the
>>>universe really contains a set of consisting of all the possible
>  >>attitudes
>>But it seems to me that you have already accepted that. Persons
>>exist, and persons have attitudes: surely it follows that attitudes
>>exist, does it not?
>Only if we accept the NL assertion that persons have attitudes at
>face value, as asserting that there is a "thing" associated with each
>person that is the person's attitude.
>>>... Maybe there is and maybe there
>>>isn't a real set of all possible attitudes.  I don't know.  From what
>>>I know of psychology and neurophysiology, I think we're a very long
>>>way from a theory of attitude to which I would give cre
>>Oh, sure. Attitudes are part of a folk psychology, just as entities
>>like 'pool of water' are part of folk physics. But that is a
>>different kind of distinction. Do mirages exist? In a sense yes, in
>>another sense no. But we can certainly talk about them.
>Yes. We talk about attitudes and mirages.  This talk is often very
>useful.  It has survival value -- literally, in the case of my cancer
>survival example.
>>>...Fortunately, I don't think it is necessary to believe there really
>>>*is* a set of all possible attitudes, and that each person really
>>>*does* have an attitude that is an element of this set, in order to
>>>accept the above theory as a useful representation of reality for
>>>some purposes.
>>Quite. I think you are taking phrases like "really" too seriously here.
>I don't think so.
>>The point I was making was that (in your example) the fact that the
>>ontology is formalized and has a formally described semantic theory
>>is not a sufficient grounds in itself for claiming that the worlds
>>it describes aren't real.
>Of course!  The set of all human beings is real.  But I am not at all
>sure that the set of all attitudes is real.  I think it may well be a
>modeling fiction that is useful for some purposes, but will be
>superceded by an appropriate scientific theory of attitude some day.
>Even after it is superceded, the parts that were historically found
>to be useful, e.g., models of how to intervene to affect cancer
>patients' attitudes and thereby help them to live longer -- will
>remain useful, even if a literal interpretation of the model's
>assertions is factually incorrect.
>>If one believes that attitudes are real, then one can speak of sets
>>of them; also, in fact, if one believes they are not real.
>Of course.
>My point is that there may be aspects of the world that we describe
>coarsely using nouns like attitude, that may be nothing at all like
>what our theories assert them to be, yet those theories may still be
>>>...I can make perfectly good use of this theory, while thinking that
>>>the idea of a set of all possible attitudes is utter nonsense.
>>Yes. Ontologies can be wrong and yet still useful.
>>>...I don't think one needs to believe that
>>>the Universe really is a set in order to make effective use of
>>>logical theories that represent the Universe as a set.
>>True, but my original point was rather the inverse: one can believe
>>the universe is a set, without thereby being obliged to abandon ones
>>belief that it is populated with real things. I think we agree on
>>this as well.
>We are in violent agreement on both points.
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>    (04)

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