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Re: [ontolog-forum] Ontologies and individuals

To: ontolog-forum@xxxxxxxxxxxxxxxx
From: Richard Dapoigny <richard.dapoigny@xxxxxxxxxxxxxx>
Date: Sun, 16 Dec 2012 18:55:51 +0100
Message-id: <50CE0B27.1060402@xxxxxxxxxxxxxx>
Le 16/12/2012 18:39, John F Sowa a écrit :
> Hans, Doug, William, Pat, et al.,
>
> I'd like to make a few observations about logic, set theory, and
> mereology, which I hope will end this thread once and for all.
> But I realize this is a forlorn hope for any topic in Ontolog Forum.
>
> HP
>> Remember that the conceptual flight object also has a life cycle,
>> not just the individual flight instances...
> DF
>> Just because something has properties, it doesn't mean that
>> that thing is an individual...
> WF
>> As Hans and Mathew emphasize, the sine-qua-non of an *individual*
>> is that it has a life cycle...
> The basic terms of ontology should not depend on anything as complex,
> undefined, and undefinable as "life".  Even the word 'cycle' requires
> some kind of ontology.  And the basic terms should be independent of
> 3D or 4D or even any notion of space and time.
>
> I agree with Pat:
>
> PH
>> Member of is the classical name for the (inverse of the) relation
>> between a set and something in that set... AFAIK, the part/whole
>> relationship described by mereology is never referred to using
>> "member" or any grammatical variation. Also, "member" is virtually
>> synonymous with "instance", if one identifies classes as sets
>> (which is commonly, though not universally, done.)
> The word 'ontology' comes from the Greek 'on' (being).  The Latin
> translation of 'on' is 'ens' (being).  In Latin, the participle 'ens'
> was nominalized as the noun 'entitas', which was borrowed as the
> English noun 'entity' in the 16th century.
>
> To be as neutral as possible, I recommend the word 'entity' for
> anything that exists in any way.  Since any formal ontology must,
> by definition, be stated in some logic language L, we can use
> Quine's criterion for existence:
>
>      "To be is to be the value of a quantified variable."
>
> But there are logics that do not have variables.  However, they
> do have ways of using some kind of names.  In Common Logic, there
> are names bound by quantifiers and names not bound by any quantifier.
> So I'll use 'name' as the more general term that includes variables
> as a special case:
>
> Definition:  For any logic L and ontology O stated in L, an *entity*
> is whatever can be indicated, selected, or referred to by a name
> or variable of L in any proposition P of the ontology O.
>
> As Pat said, defining an individual as an entity that does not have
> members requires an ontology of sets (or other collections) for which
> a dyadic relation memberOf(x,y) or elementOf(x,y) has been defined:
>
> Definition:  For any logic L and ontology O stated in L, if O makes
> a distinction between entities called sets and entities that are not
> sets, then an *individual* is any entity that is not a set.
>
> Mereology is a theory that uses the partOf relation instead of memberOf
> or elementOf.  In mereology, the sum of two or more entities is another
> entity.  Therefore, the term 'individual' is not defined.
>
> However, the term 'individual' literally means something that cannot
> be divided.  So you could define an individual in mereology as an
> entity that does not have parts.  But that's your choice.
>
> Summary:  If you want to use the term 'individual' in an ontology
> that does not include sets, then adopt the Humpty-Dumpty principle:
> let the word mean anything you want it to mean.  But then you have
> the obligation to state precisely what you mean.
>
> John
Hi all,
John , you are right but the problem with mereology and set theory is 
that many works choose the framework of set theory and use mereological 
definitions (e.g., part-of, proper-part-of, weak or strong 
supplementation principle and the like) without stating explicitely that 
they are not in a "pure" mereological framework.
Richard    (01)

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-- 
And the wounded skies above say
it's much too much too late.
Well, maybe we should all be praying for time.    (03)

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