Message-Id: <199503010623.AA11850@nfs2.digex.net>
From: jorge@PHYAST.PITT.EDU
Date: Wed Mar  1 01:23:26 1995
Subject:      Re: On {lo} and existence
X-From-Space-Date: Wed Mar  1 01:23:26 1995
X-From-Space-Address: LOJBAN%CUVMB.BITNET@uga.cc.uga.edu

And:
> If S is a sentence containing {lo broda}, and D is the set of propositions
> derivable from S (by grammatical rules), then it is always possible
> to find in D a proposition that is true in this world, and a proposition
> that is false in this world. The same goes for sentences containing
> {le broda}.

I think this is probably true with any interpretation of {lo}.

If I understand correctly, a sentence is any string of words that makes
the parser happy. I agree with you that sentences defined like that can't
be said to have truth values. An utterance is an instance of use of a
sentence. This is what can have a truth value.

I'm not sure about the relationship between the set of propositions
and the utterances, though.

> However, even if many propositions can be derived from a given sentence,
> when we utter it there is a guarantee that all but one of these
> propositions is to be rejected.

Ok, but what about in the other direction. Is it possible that more
than one utterance map to the same proposition? If not, then there's
no point in distinguishing propositions from utterances, since they
would be matched one to one.

If yes, then propositions are only a rough coarsening of what we
transmit by utterances, and in that case I don't agree that there
is an objective way of assigning a proposition to a given utterance.
Either the assignment will be precise but arbitrary, or not so
arbitrary but then quite imprecise. In the last case in borderline
cases you can't guarantee the rejection of all but one proposition
for a given utterance.

> Consider {le cukta cu blanu}. From
> this we can derive an infinitude of propositions, differentiated
> by which individual(s) {le cukta} denotes.

Yes, and even for the same individual, we still have an infinitude
of utterances differentiated by the speaker, the audience, the time
and place of the utterance, etc. These also can have different truth
values, so I suppose that they correspond to different propositions.
I'm not clear how you would obtain those propositions through
grammatical rules (and not having them coincide one-to-one with
the utterances).

> But if I utter that
> sentence you know that all but one of those propositions has been
> discarded; this is because the denotation of {le cukta} gets fixed.

But not only because of that. Also because we, as speakers of the
language, are in agreement as to the meaning of {blanu}, and also
we are present at the scene of the utterance and can therefore make
sense of it.

> Exactly the same applies to {mi terxra lo cukta}, where {lo cukta}
> adds "in universe U x is a book". From this too we can derive an
> infinitude of propositions, differentiated by which universe universe U
> is. And similarly, if I utter that sentence you know that all but one
> of those propositions has been discarded; this is because the identity
> of U gets fixed. And, like every proposition, this undiscarded one
> must be either true or false.

Right, but why don't you call that nonveridicality? Just as in
{le cukta} it doesn't really help us to know what the predicate {cukta}
means, then in {lo cukta} it doesn't either. We must go inside the
speaker's head to know what is being refered as {le cukta}, or to know
what things satisfy {cukta} in that imaginary universe.

You may argue that the meaning of {cukta} in that universe will be
much related to the meaning of {cukta} that we know, otherwise why not
use some other word, since in principle in that universe we could
redefine every selbri. But exactly the same applies to {le cukta}.
There is a reason why the speaker chose to say {le cukta} over
{le panka}.

> Now, consider {mi terxra lo -balrog}. Now that sentence, abstracted
> from any context, can mean "I drew a tulip", and to that extent it
> is nonveridical.

Right.

> But turn this sentence into an utterance, and it
> is associated with exactly one proposition. So let's pick a certain
> utterance of that sentence: this utterance is associated with
> the proposition:
>   Ex in This World I drew x & in Middle Earth x is a balrog

(As an aside, do you agree with me that we only make believe that
we can write down propositions? What you wrote down is a sentence,
but because it is a bit more precise than ordinary, we accept to
call it a "proposition".)

> I maintain [without necessarily believing] that that can't mean
> "I drew a tulip", in the sense that there is a tulip that the picture
> resembles.

Then you should add to your "proposition", & in This World x is not
a tulip, otherwise how can we tell that the Middle Earth balrog isn't
a tulip here? What you drew could be anything of this world, as long as
it is a balrog in M.E. If all balrogs of M.E. are tulips here and
viceversa, then it means exactly the same as "I drew a tulip".
(We are assuming here that in English "a tulip" _is_ veridical,
at least when writing down "propositions".)

> Now contrast that with something genuinely nonveridical:
> {le gerku cu xekri} can truthfully be said of a tulip.

So can the other one. They seem equally nonveridical to me, being
different only in specificity.

> > (The concept of "imaginary" is already a predicate, I don't see
> > the need to make it a metapredicate.)
> How would that work? The set of imaginary wings is not formed from
> the intersection of the set of wings and the set of imaginaries.

Of course not. If you like, it is the intersection of things imaginary
and things that look like wings, although it's not quite that either.

> Or would you take the view that the set of wings includes imaginary
> wings, but when we speak of {lo nalci} there is a presumption that
> we are quantifying not over the set of wings but over the intersection
> of the set of wings and the set of reals?

No, I don't take that view. The quantifiers quantify over all things
that we can predicate about, and these are often not real. All they
need to do is satisfy some predicate, and we can quantify over them.

> > > You may be right. How would you unraise draw-a-pic-of?
> > You have to explain the predicate better. "Take a photograph of" is
> > clearly not a problem, the object is a real object. For drawing
> > a picture, the case is the same if the x2 is the model. If the
> > model x2 is not a really-is broda but a generic or somesuch, then
> > don't use {lo}.
> The x2 of the predicate I had in mind is not the model but the
> "subject-matter".

I don't see the difference. What would be an example of subject matter?
If I draw a picture of my cat (if I had one) would the subject matter
be anything other than my cat? That's what I meant by model.

> > _Every_ {nu <bridi>} would be a potential event.
> I see no difference between your definition of {nu} and my observation
> that {lo nu} defaults to {lo dahi nu}. Maybe you see no difference
> either.

The difference is that you make {da'i} come from {lo}, and I make it
come from {nu}. {da poi nu <bridi>} would still be a potential event
for me, but presumably a happening event for you.

> It's exceptional because it's not verifiable. All other selbri can
> be verified/falsified by inspecting the world. Put another way:
> however you restrict the category, it always remains non-empty.

Yes, that's why I don't like it, I think events should be non-vacuously
quantifiable, like all other space-time enduring objects.

But it wouldn't be an exception, at least not the only one. Du'u works
like that too. {lo'i du'u <bridi>} is never empty.

> ({lohi nu broda gihe na broda} would fairly clearly be non-empty,
> but lo dahi god knows whether {lohi nu broda kei gihe na nu broda}
> is non-empty.)

It is empty, but it is not of the form {lo'i nu <bridi>}.

In any case, I like it less and less the more I think about it.

> > > Any of these three is okay by me.
> > My first choice would be that {nu broda} be a real event of brodaing.
> > I can accept it being a potential event of brodaing, but I'd hate to
> > let {lo broda} be anything other than a this-world broda.
> > ("This world" being the world in which the discourse takes place.)
>
> I think that of those who've expressed a view, only Lojbab doesn't
> go along with your first or second choice,

But I doubt he accepts your third proposal. That would mean accepting
that {lo ninmu cu nanmu} can be true in this ordinary world. How are
we going to teach the nonveridicality of {le} if that is so?  :)

> though of the remainder
> I don't know whether it is your first or your second choice that
> they prefer. John & pc said they agree with you, but the status
> of {nu} wasn't mentioned.

I'm becoming convinced that the only way to have opaque contexts
(without tu'a, xe'e, lo'e, etc) is to use {du'u}, and not {nu}.
I suspect that with {nu} used for really-happen events, its
quantifiers should always be exportable. And I believe that this
may have to do with {du'u} meaning "x1 is what we make believe
to be the proposition associated with the sentence:<bridi>". The
quantifiers belong to the proposition, and so we can't take them
out, but they don't belong to really happening events.

Even if we don't end up concluding anything, I'm having a lot of
fun with this discussion.

Jorge