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Re: [ontolog-forum] Ontology, Information Models and the 'Real World':

To: Pat Hayes <phayes@xxxxxxx>, Ontolog Forum <ontolog-forum@xxxxxxxxxxxxxxxx>
From: Waclaw Kusnierczyk <Waclaw.Marcin.Kusnierczyk@xxxxxxxxxxx>
Date: Mon, 11 Jun 2007 18:37:12 +0200
Message-id: <466D7A38.6070506@xxxxxxxxxxx>
Pat Hayes wrote:
>> Pat Hayes wrote:
>>>> Pat Hayes wrote:
>>>>
>>>>>>> (forall (c)(ist c (that (rains))))
>>>>>>> In IKL, a relation with no arguments is itself a proposition, so 
>>>>>>> one could write it without the "that":
>>>>>>>
>>>>>>> (forall (c)(ist c rains))
>>>>>>
>>>>>> Just a syntactic feature?
>>>>>
>>>>> Yes, essentially. It is way that the use/mention distinction 
>>>>> applied to propositions comes out in the IKL syntax.
>>>>
>>>> So if
>>>> (that (rains))
>>>>
>>>> is equivalent to
>>>> rains
>>>>
>>>> , is
>>>> (that (dead osama))
>>>>
>>>> equivalent to
>>>>
>>>> "dead osama"
>>>> ?
>>>
>>> I guess it might be if that last expression were legal IKL syntax, 
>>> but it isn't. You can only get away with this trick when the relation 
>>> has no arguments.    (01)

So it is quite the opposite:  it *is* legal, but not equivalent to the 
other expression.    (02)

>>
>> Why would this not be syntactically legal?  You do use quotes to 
>> delimit names that include spaces, right?  "osama bin laden" is legal 
>> syntax, and "dead osama" is not??
> 
> Sorry, you are quite correct. I was reading your quotes as part of the 
> email, not part of the IKL. But then these are not equivalent: in fact 
> they are not logically related at all, any more than Patrick is related 
> to trick. As you say:
> 
>> The problem I see is that IKL could not consider (that (dead osama)) 
>> equivalent to the (syntactically legal!) "dead osama" because the 
>> latter is understood as an atomic name, so it would not be parsed into 
>> "dead" and "osama".
> 
> Yes, exactly.
> 
>>  But you can well say
>>
>> (= "dead osama" (that (dead osama)))
>>
>> , can't you?
> 
> You can say it as an axiom, but it's not a logical tautology. This is:
> 
> (= "dead osama" (that ("dead osama")))
> 
> but of course (dead osama) and ("dead osama") have no logical 
> relationship to one another.    (03)

Of course.    (04)

vQ    (05)

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