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Re: Peter's example

From: <jos.deroo.jd@belgium.agfa.com>
Date: Sun, 6 Jan 2002 01:30:44 +0100
To: pfps@research.bell-labs.com
Cc: jos.deroo.jd@belgium.agfa.com, www-webont-wg@w3.org
Message-Id: <OF067E0816.BF4E564D-ONC1256B39.0000F8C6@bayer-ag.com>

> > > > Oops, swapped lhs with rhs...
> > > > what I said was about N3 rules lhs, but you asked about their rhs
> > > > well, that is Prolog clauses's lhs, which is the consequence
> > > > and that is also a set of triples (actually one 'normal' triple
> > > > but there could be further triples describing bNodes)
> > > > that set of triples is also *not* asserted, only the statement
> > > >   premis log:implies conclusion .
> > > > is asserted
> > >
> > > But what is the meaning of the entire statement then?
> >
> > true
> >
> Not helpful.
> If this is its meaning then what is Euler doing?
> I'm trying hard to determine what the meaning of owl-rules.n3.  If it has
> no meaning beyond its status as a triple with a non-logical predicate then
> what is Euler doing?  If it has a meaning then what is it?

well, sorry to have been so short (and maybe bold), but
we invited some people this evening and they just came in
at that moment...
it is mainly as Pat Hayes said
Logic is about characterising how truth is preserved. The idea
isnt that formal systems are true (actually that doesnt mean
anything), but that the formal systems *preserve* truth: it the
antecedents are true (in I) then the consequents must be true (in I).
That 'if..then' is what has to be true for any I if the reasoning is
valid. The point being that if I have no idea what your intended
interpretation is (which in general I don't, in fact, other than
knowing that it makes your assertions true), then that doesnt matter;
I can still draw valid conclusions from your sentences since
*whatever* your intended interpretation was, my conclusions will be
true in it.
Validity means preservation of truth; an inference is valid when the
conclusion is true in every interpretation which makes the
assumptions true. Adding extra information to the assumptions should
not make a valid inference become invalid.

that's what we try to do...

Received on Saturday, 5 January 2002 19:31:22 UTC

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