Re: SUO: Re: The lattice of theories + language-games
(The following reply was sent at 10:36 a.m. PST on 6/14/2002, but it never
made it onto the SUO list archive. Perhaps the server was too busy with
viruses at that time ;^)
Hi Chris,
----- Original Message -----
From: "Chris Menzel" <cmenzel@tamu.edu>
To: "IEEE Standard Upper Ontology List" <standard-upper-ontology@ieee.org>
Sent: Friday, June 14, 2002 6:39 AM
Subject: Re: SUO: Re: The lattice of theories + language-games
> Robert Kent wrote:
> > A 1st-order language L consists of
> >
> > * a set of entity types (sorts) ent(L), where examples of entity types
> > might be Person, Organization, Emotion, etc;
>
> So a language for you comes pre-packaged with a particular semantics?
No. How so? Person and Organization are intended to be just type names,
whereas "Chris Menzel" and "Texas A&M University" would be instances of
those types.
A language L might have Person and Organization as elements in its entity
type set ent(L). However, it normally would not have "Chris Menzel" and
"Texas A&M University" in any of its sets (variable, entity type, function
type, or relation type).
> > * a set of variables var(L) that is often of the form var(L) = ent(L) x
> > natno the binary Cartesian product of entity types and natural numbers;
>
> Hm, so if ent(L) = Person, then an example of a variable might be the
> ordered pair <Robert Kent, 17>? Is that really what you mean?
No, two problems here. First, Person might be an element of ent(L), but
would not be the whole set. And second, a variable might be <Person, 17>,
which might be abbreviated person_17, but <Robert Kent, 17> would not
normally be a variable, since "Robert Kent" is an instance, not a type. The
variable <Person, 17> would reference (have sort) the entity type
refer(L)(<Person, 17>) = Person.
There are no instances in either IFF languages or IFF theories. Instances
come into the picture in IFF models and IFF logics.
> It's difficult to distinguish syntax and semantics here, as
> traditionally understood, anyway.
I apologize for the terseness and abstraction. The terseness is my problem,
the abstraction is in the nature of the thing. Please keep asking questions.
And thanks for these.
Robert E. Kent
rekent@ontologos.org