Re: On {lo} and existence

[ucleaar <ucleaar@ucl.ac.uk>]

Jorge:
> > I assume that by default every bridi is {dahinai}, unless there
> > is overt {dahi}. So {lo ninmu cu nanmu} = {dahinai lo ninmu cu
> > nanmu}, which says:
> >    [In some universe, Ex x is a woman] and [in this universe,
> >     x is a man]
> > Perhaps if we allow this universe to contain individuals who
> > also exist in other universes, that could be true. It depends
> > on your metaphysics, so Lojban should be neutral on this
> > matter.
> I don't understand. Suppose I dream that I'm a woman. Then
> it is true that {lo ninmu cu nanmu} right?

Only if in the dream there is a woman that is a man, and this is
possible in the dream world. Even if you dreamt you're a woman,
I don't think it would be true to say (of this world) {lo ninmu
cu nanmu}. It would, however, be true to say {mi senva lo ninmu},
"In this world I dreamt of something that in another world is a
woman".

> > > So you are accepting that {ro broda cu broda} can be false.
> > > To me, that is an abomination.
> > I am accepting it can be false. I don't see why it's an
> > abomination. I don't even find it counterintuitive.
> Not only can be false, but must be false. Here is the proof:
> For the broda under consideration, find a ko'a such that
> {ko'a broda} is false. (If there is no such ko'a, then broda
> must be very peculiar, but for most broda there will be one).
> Now imagine a universe where {ko'a broda} is true.
> Then {ro broda cu broda} must be false, because there is at
> least one {lo broda}, namely ko'a, which na broda.

I thought you wished to argue that {ro broda cu broda} must
be true. I suppose you mean that under my current position
it must be false. Well, it needn't be false. Here's why.
This is what I'm claiming {ro broda cu broda} entails:

  U [an in-mind constant] is a universe. In U there is a set, s.
  For every x, if, in U, x is a broda, then x is a member of s.
  R [an in-mind constant] is what we are currently taking to be
  the real universe.
  In R, very member of x is a broda.

If U = R, then {ro broda cu broda} is true.

Let's look at your proof:

> For the broda under consideration, find a ko'a such that
> {ko'a broda} is false.

Okay. Koha = me, AR. Broda = ninmu.

> Now imagine a universe where {ko'a broda} is true.

Ok. Recalling dreams of confused adolescence....

> Then {ro broda cu broda} must be false, because there is at
> least one {lo broda}, namely ko'a, which na broda.

{ro ninmu cu ninmu} can be true in both real world and this
dream world where I'm a ninmu, so long as the universe in which
the membership of the set containing lahe {ro ninmu} is the
same as the universe in which these members are ninmu. I.e. if
universe U is universe R.

> > > then there can be no argument that {da poi broda} is equivalent to
> > > {lo broda}, just as {roda poi broda} is equivalent to {ro broda}.
> > I think neither of these equivalences hold. (I have decided to
> > assume option [3] on my list of possible meanings for {lo}, on
> > the grounds that it is most consistent with current usage.)
> Consistent? It makes practically every claim about {lo broda} true:
> Say I want to prove that {lo broda cu brode} is true.
> All I need to do is find something that really is a brode in this
> universe. Then imagine a universe where that something really is a
> broda, and voila {lo broda cu brode} becomes true in our universe.
> In other words, if for some da, {da brode} is true, then for every
> broda, {lo broda cu brode} is true.

I see what you're saying. The problem comes from taking {lo broda}
to mean:

  Ex, x is a universe, and in x, Ey, y is a broda

- according to which everything you say is true, whereas I think it
should mean:

  In universe U, Ey, y is a broda.

- in which case, to test whether {lo broda cu brode} is true, you
first have to ascertain which universe is U.

> What is the point of having {lo} if every claim made with it
> is vacuously true?

None at all, but I don't think every claim made with it is vacuously
true.

> > Can the following both be true at the same time?
> >
> >   {mi skicu lo nalci be mi}
> >   {no da nalci mi}
> >
> > I want these both to be true at the same time.
> They can't both be true, they are contradictory (assuming all tenses
> are the same, no tricks like {mi skicu lo pu nalci be mi} and
> {no da ca nalci mi}, or worse: {mi skicu lo ka'e nalci be mi} and
> {no da ca'a nalci mi}).

No tricks. The usefulness of both being true at the same time
is obvious. It's in the nature of seskicu that they needn't
exist in the universe in which they are described. "I described
my wings" doesn't entail "I have wings". If they can't both
be true, then {lo nu} must denote something that really happens.
That would be very inconvenient.

---
And