Re: POOD and the Unique Name Assumption

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.

Marshall Received on Wed Jun 11 2008 - 19:29:30 CEST