Message-Id: <m0quY2w-00005XC@xiron.pc.helsinki.fi>
Date:         Mon, 10 Oct 1994 23:35:08 -0400
Reply-To:     Logical Language Group <lojbab@ACCESS.DIGEX.NET>
Sender:       Lojban list <LOJBAN%CUVMB.bitnet@FINHUTC.hut.fi>
From:         Logical Language Group <lojbab@ACCESS.DIGEX.NET>
Subject:      Re: lo [nonexistent]
To:           Veijo Vilva <veion@XIRON.PC.HELSINKI.FI>
Content-Length: 1450
Lines: 33

UC>> >But your examples would translate as "ro elf" or "lohe elf", not as
UC>> >"lo elf".
UC>> >
UC>> >We need different examples where we want to discuss hypothetical
UC>> >but nonexistent objects using "lo".
UC>>
UC>> I can't say for sure about "lo'e", but this does not work for "ro elf".
UC>> If the statement "ro [elf] cu [has pointed ears]" is true, then so is
UC>> "ro [elf] cu [has unpointed ears]" and "ro [elf] na [has pointed ears]".
UC>
UC>I don't see this. But anyway, what matters is what would be true
UC>if elves exist.

Well, in English:

Assume that there are no elves.

All elves are green is a true statement, because you cannot disprove it
by showing me a non-green elf.  (I have been told that this is why "all"
has no existential import, unlike "there exists").  But also "all elves
are red" is true by the same logic, as well as "all elves have pointed ears"
and "all elves have unpointed ears".

You are talking about all members of the empty set, and by definition you
jhave to decide that all statements about the empty set are true by the
above logic, or false (in which case I think you can get similar problems,
but am not sure what they are - possibly also with negations), or meaningless
(an answer not to satisfying in the intersection of logic and set theory.

(Warning - I am talking throuigh my hat here.  Nora has tried explaining this
to me a few times, but I readily admit that I only half understand.)

lojbab