>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.
>
>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?? (01)
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: (02)
>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". (03)
Yes, exactly. (04)
> But you can well say
>
>(= "dead osama" (that (dead osama)))
>
>, can't you? (05)
You can say it as an axiom, but it's not a logical tautology. This is: (06)
(= "dead osama" (that ("dead osama"))) (07)
but of course (dead osama) and ("dead osama") have no logical
relationship to one another. (08)
Pat (09)
>
>vQ (010)
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