# Re: POOD and the Unique Name Assumption

From: Brian Selzer <brian_at_selzer-software.com>
Date: Thu, 12 Jun 2008 07:21:46 -0400
Message-ID: <eF74k.7882\$mh5.5828_at_nlpi067.nbdc.sbc.com>

> 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
>>>
>>>
>>>
>>>>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.

The unique name assumption is concerned with how first order language elements are mapped to objects in the Universe of Discourse. How could forcing that mapping to be bijective cause aliasing errors? Received on Thu Jun 12 2008 - 13:21:46 CEST

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