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Re: Interpreting sumti (was: anaphor means what?)
- To: lojban-list
- Subject: Re: Interpreting sumti (was: anaphor means what?)
- From: cowan (John Cowan)
- Date: Wed, 1 May 91 11:41:43 EDT
- In-Reply-To: <9104301552.AA14152@euphemia.math.ucla.edu>; from "math.ucla.edu!jimc" at Apr 30, 91 8:52 am
djim. kartr. writes:
> What I really want to hear about is the "problem of the empty set". When
> is a sumti veridical -- which I take to mean has a hidden implicit
> existential quantifier in it? And when is a void referent set simply
> ignored, producing a vacuously true assertion? Take for an example:
>
> The dodo lives on Ascension Island
>
> to be translated with "lo". The X1 sumti (all things that really are
> [alive] dodos) has a void referent set. What problems arise here?
You have the distinction exactly backwards. (First, a minor side issue:
Lojban "da" is Old Loglan "ba", not Old Loglan "da". Do you have this
firmly in mind? Some of your remarks on "da poi" make me wonder if you
are hearing this "da" as free rather than bound. Non-Old-Loglanists,
ignore this.)
A veridical description is precisely >not< one that has a hidden existential
quantifier; "da poi" is the one with the implicit existential quantifier.
Therefore, "da poi <selbri>" can't ever refer to the null set, because "da"
is implicitly existentially quantified unless some other quantifier appears
on it.
"lo <selbri>", on the other hand, is free to reference the null-set-in-
extension, in other words nothing.
lo cipnrdodo cu xabju le daplu se cmene zo .asencn.
Those-which-are bird-"dodo"s dwell-on the island named "Ascension".
is vacuously true, whereas
da poi cipnrdodo cu xabju le daplu
Something such-that [it] is-a-dodo dwells on the island.
is false, because it contains an implicit (not hidden) existential quantifier
on "da", and is in fact the same as:
su'o da poi cipnrdodo zo'u da xabju le daplu
There exists a dodo: it dwells on the island.
"Veridicality", OTOH, has to do with whether the object described is required
to actually meet the description. The sentence
mi catlu lo cribe
I look-at a bear.
is true only if, in fact, the object I am looking at is a bear, whereas
mi catlu le cribe
I look-at the bear.
can be true even if the object I am looking at turns out to be a raccoon.
"le" descriptions are "non-veridical" because the truth of the bridi in
which they are embedded is independent of the truth of the description.
(It seems to me, based on your use of the phrase "in-mind selection"
when explaining -gua!spi "xe", that the superficially analogous
!ji /knl !berw
is true only if the referent of X2 place is in fact a bear, although I am free
to choose any bear I like without sacrificing truth.)
--
cowan@snark.thyrsus.com ...!uunet!cbmvax!snark!cowan
e'osai ko sarji la lojban