# Re: A pk is *both* a physical and a logical object.

From: Brian Selzer <brian_at_selzer-software.com>
Date: Thu, 19 Jul 2007 17:39:26 GMT
Message-ID: <ilNni.50659\$5j1.5100_at_newssvr21.news.prodigy.net>

"Jan Hidders" <hidders_at_gmail.com> wrote in message news:1184860573.502673.208300_at_g4g2000hsf.googlegroups.com...

```> On 13 jul, 16:54, "Brian Selzer" <br..._at_selzer-software.com> wrote:
```

>> "Jan Hidders" <hidd..._at_gmail.com> wrote in message
>>
>>
>>
>>
>> > On 13 jul, 06:17, "Brian Selzer" <br..._at_selzer-software.com> wrote:
>>
>> >> I was thinking more along the lines of the difference between what can
>> >> be
>> >> and what can be true.
>>
>> > Very little, I imagine. :-)
>>
>> {a, b, c} is different from {{a}, {b}, {c}}, yes? A description of the
>> universe is a description of what can be. What can be true is a
>> description
>> of a description of what can be.
```>
> I don't see a distinction between "can be" and "can be true", for me
> those are synonymous. Perhaps you meant "is" and "can be"? Note that
> the UoD is anything you might want to talk about, and therefore
> usually describes what "can be" and not just "what is".
>

```

So, what you're saying is that existence is identical to truth?

>> > So you meant static constraints? Why do you think those would not be
>> > part of the description of the UoD?
>>
>> I was thinking more along the lines of relation schemata, which can be
>> represented either by open sentences in first order logic (which if
>> included
>> as part of the description of the universe would mean that that
>> description
>> is incomplete) or by contingent sentences in quantified modal logic. In
>> either case an assignment is required to obtain what is actually true
>> their referents, and by extension, about the universe.

```>
> Why restrict yourself only to those logics? Anyway, all that is part
> of the UoD.
>
```

>> So, at the logical level, you describe not only the Universe of
>> Discourse,
>> but also what can be said about the Universe of Discourse.
```>
> That is by definition also part of the UoD.
>
> -- Jan Hidders
>
```
Received on Thu Jul 19 2007 - 19:39:26 CEST

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