Re: POOD and the Unique Name Assumption

From: Bob Badour <bbadour_at_pei.sympatico.ca>
Date: Wed, 11 Jun 2008 16:33:06 -0300
Message-ID: <4850285e$0$4058$9a566e8b@news.aliant.net>


Marshall wrote:

> On Jun 10, 5:05 pm, "Brian Selzer" <br..._at_selzer-software.com> wrote:
>

>>"Marshall" <marshall.spi..._at_gmail.com> wrote in message
>>
>>news:ca56ebe8-5736-4de9-af01-b635c8baece1_at_w34g2000prm.googlegroups.com...
>>
>>
>>>On Jun 9, 6:02 am, "Brian Selzer" <br..._at_selzer-software.com> wrote:
>>>
>>>>Does the Unique Name Assumption apply only to individuals, or does it
>>>>apply
>>>>also to relations?  Under an interpretation where constant symbols are
>>>>mapped to individuals and predicate symbols are mapped to relations, if a
>>>>and b are constant symbols and P and Q predicate symbols and if neither
>>>>aPb
>>>>nor aQb fail to denote, can aPb ever mean exactly the same thing as aQb?
>>
>>>>And if the Unique Name Assumption does apply also to relations, then what
>>>>impact does that have on POOD?
>>
>>>I guess I don't really know  what this "Unique Name Assumption" is.
>>
>>The Unique Name Assumption ensures that whenever two names are different,
>>the objects they represent must also be different.

>
>
> What is motivation for such an assumption? It doesn't seem to hold in
> any formal system I can think of.
>
>
>
>>>But ordinarily, the mapping from names to things being named
>>>is a function, but not necessarily the reverse.
>>
>>>As to whether aPb can ever mean the same thing as aQb:
>>
>>> 2+0 = 2-0
>>
>>The /result/ of 2+0 is the same as the /result/ of 2-0, but is the meaning
>>of an expression the same as the result of the expression?  It seems to me
>>that how one arrives at a result can be just as important as the result.
>>For example, if a man turns left onto the sidewalk in front of his house and
>>then proceeds around the block, he will end up at the exact same place as if
>>he had turned right onto the sidewalk and then proceeded around the block.

>
>
> Sure.
>
> "2+0" != "2-0"
>
> However
>
> 2+0 = 2-0
>
> It seems straightforward enough. "2+0" and "2-0" are two
> different names, expressions specifically, for the same thing.

The unique name assumption sounds like asking for aliasing errors. Received on Wed Jun 11 2008 - 14:33:06 CDT

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