Re: [lojban] {zo'e} as close-scope existentially quantified plural variable

[Jorge Llambías <jjllambias@gmail.com>]

On Fri, Oct 14, 2011 at 7:39 AM, And Rosta <and.rosta@gmail.com> wrote:
> Martin Bays, On 13/10/2011 05:33:
>
>> (For nastier a example, consider the apparently classic {ro te cange poi
>> ponse lo xasli cu darxi ri}... although I'd be happy simply considering
>> this to be meaningless)
>
> Do you mean the Lojban is meaningless, because of the inadequacy of the
> rules for identifying and interpreting the antecedent of {ri} (in which case
> I'm sure you're right)?

I would say the Lojban is meaningful and (roughly) equivalent to
"every farmer who is a donkey-owner is a donkey-beater". There is a
natural inference from there that the instance of Donkey that makes a
given farmer a donkey-owner is the same instance that makes them a
donkey-beater, but this is not a logical inference from the Lojban
sentence, which has no quantification over donkeys, it's just a
natural inference from knowledge of how the world works with respect
to ownership and beatings. From another sentence with the same
structure but different content, like "ro te cange poi vecnu lo tamca
cu citka ri", "every farmer who sells tomatoes, eats them", "every
farmer who is a tomato-seller, is a tomato-eater", we would be less
tempted to make the corresponding inference.

The English version is more complicated, because it does contain a
distinction that the Lojban does not. There is a contrast in English
between "every farmer who owns a donkey beats it" and "every farmer
who owns a donkey beats one", so if we want to capture the
quantification over donkeys in Lojban we are forced to go with
something like:

  ro da poi xasli zo'u ro te cange poi ponse da cu darxi da

This is not an ideal translation of the English though. The English
sentence has all these components:

(i) The farmers as theme.
(ii) Explicit quantification over farmers.
(iii) Implicit quantification over donkeys.
(iv) Reasonably concise structure.

while the Lojban version above has:

(i) The donkeys as theme.
(ii) Explicit quantification over farmers.
(iii) Explicit quantification over donkeys.
(iv) Relatively complex structure.

If we want the farmers as theme, we need to make some logical transformations:

   ro da poi xasli zo'u ro te cange poi ponse da cu darxi da
= ro da poi xasli zo'u ro de poi te cange zo'u ga nai de ponse da gi de darxi da
= ro de poi te cange zo'u ro da poi xasli zo'u ga nai de ponse da gi de darxi da
= ro de poi te cange zo'u de darxi ro xasli poi de ponse ke'a
= ro te cange cu darxi ro xasli poi ri ponse ke'a

I'm assuming that in Lojban the theme is what's in first position,
which may or may not be a correct assumption but seems reasonable
enough.

I'm also assuming that when the antecedent of "ri" is a "ro broda"
expression, then "ri" stands for the implicit variable bound by the
quantifier. This is something that needs to be explored, but I think
makes some sense.

Now we have:

(i) The farmers as theme.
(ii) Explicit quantification over farmers.
(iii) Explicit quantification over donkeys.
(iv) Reasonably concise structure.

which is almost like the English, except that the quantification over
donkeys is explicit in Lojban and the structure is still concise but
somewhat different.

And of course this does not logically follow from "ro te cange poi
ponse lo xasli cu darxi ri", although it does follow naturally enough
if we factor in our general knowledge of the world.

>The proposition intended by donkey sentences is easy
> to grasp, and pretty commonplace, but hard to formulate in ordinary logic; a
> logical language should find a way to render the proposition into logic and
> express it succinctly.

Would you agree that "ro te cange cu darxi ro xasli poi ri ponse ke'a"
captures that proposition, even though it doesn't respect the original
structure? Because the structure is so different, this may not work as
a general solution to the problem.

mu'o mi'e xorxes

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