Subject: Re: [lojban] Bald men

From: [email-masked]
Date: Thu, 1 Nov 2001 04:32:09 EST

In a message dated 10/31/2001 1:55:06 PM Central Standard Time, 
[email-masked] writes:

> As pc points out, English speakers could interpret the sentence two ways:
> "each and every man doesn't have hair", or "it's not true that every man
> has hair". A logician would pick the first one, Lojban is a logical
> language, and the Lojban text is constructed accordingly.
> 

Actually, logicians regularly pick the second, as do linguists, by and large.

<Subj: Re: [lojban] Bald men   
Date: 10/31/2001 1:55:06 PM Central Standard Time 
From:    [email-masked] (James F. Carter)
To:    [email-masked]

I didn't notice that this question actually got answered.

On Sun, 28 Oct 2001, Invent Yourself wrote:
> The naku Wiki page says the following. Is it true?

jimc says: No.

> "All men don't have hair" can be represented in Lojban as
>        ro nanmu na se kerfa

As pc points out, English speakers could interpret the sentence two ways:
"each and every man doesn't have hair", or "it's not true that every man
has hair".  A logician would pick the first one, Lojban is a logical
language, and the Lojban text is constructed accordingly.

> which prenexes as
>        naku ro da poi nanmu zo'u kerfa da

No, it doesn't.  The author hoped for the second interpretation, but has
failed to use De Morgan's rules when re-ordering a negated sentence:
exchange "and" vs.  "or", and likewise exchange existential vs. universal
quantification.>

Well, yes it does. Remember that the {na} next to the selbri (and the on on 
the following connective) are actually ALREADY at the leftmost end of the 
prenex. All the quantifiers are thus already correct for that position -- it 
is remembering that that is the problem, rather than the shifting problem 
(which comes with moving {naku} back rightward.

<>        It is false that for each X that is a man, (something) isX's hair
> which is true: some men are bald.>

Correct.

<Here's my rendition:

        naku *su'o* da poi nanmu zo'u kerfa da
    It's false that for even one X which is a man, there exists
            Y [which is] the hair of X.
    All men are bald.>

This is the other version, not the one we started with. This could also be 
{roda poi nanmu zo'u naku kerfu da} to get the feel of the English.