Subject: Re: [lojban] "knowledge as to who saw who" readings

From: And Rosta <[email-masked]>
Date: Thu, 11 Oct 2001 14:44:29 +0100

Xorxes:
#la and cusku di'e
#>I continue to feel much disquiet about these issues. I think we have to be
#>able to describe the beliefs of others in terms of truth-conditional 
#>equivalence, so that "J believes that not either p or q" is equivalent to 
#>"J believes that not p and not q", for instance.
#
#I think {la djan krici le du'u naku ga broda gi brode} is
#indeed equivalent to {la djan krici le du'u genai broda
#ginai brode}. I don't think those involve different intensions.
#It doesn't require that John uses those words to express his
#beliefs either. He doesn't even have to understand what a
#conjunction or a disjunction is. He does have to understand
#the meaning of 'broda' and 'brode', but not necessarily in
#those words. If John doesn't speak Spanish I can still say
#in Spanish what his beliefs are.

Okay. So intensional descriptions of beliefs are independent of propositional
form. But we do still need a way to describe beliefs when we know their
truthconditions but not their intensional form.

#>EC1'. la djon jinvi/djuno lo -extension-member-claim be tu'odu'u ce'u 
#>viska ce'u
#>EC1''. la djon jinvi/djuno lo -true-extension-member-claim be tu'odu'u ce'u 
#>viska ce'u
#
#I'm not sure how this changes anything from your first version.
#Why would knowing a proposition, (which happens to be a member of
#the extension), be the same as knowing that that proposition is
#a member of the extension?
#
#"I know that John goes" is different from "I know that 'John
#goes' is a member of the extension of 'who goes'".

I probably failed to properly execute my intention (& can't locate my
original message to see where I went wrong), which was that lo 
-extension-member-claim (etc.) should be defined as proposition that
is truthconditionally equivalent to tu'odu'u da cmima tu'o -extension
be tu'odu'u ce'u viska ce'u, etc. The intention, then, is that given
"la djon jinvi/djuno lo -extension-member-claim be tu'odu'u ce'u 
viska ce'u", we know the truthconditions of John's belief but not
its intensional form. Is that clear?

I likened it to your set-of-answers approach because it too does not
specify the intensional form of answers.

#{mi djuno le du'u ta gerku} is not the same as {mi djuno le du'u
#ta cmima lo'i gerku}. The first one requires me to know what
#a dog is, the second one requires me to know what a member is.

Well, in one (intensional) sense they aren't the same and in another 
(truthconditional) sense they are. 

#>#SA2. la djon djuno re du'u makau viska makau
#>
#>Not really okay, because the scenario I was trying to describe was
#>one where for every x and every y such that x saw y, John knows that
#>x saw y. That seems to me to be on of several important distinct
#>readings of "John knows who saw who".
#
#Ok, that would be:
#
# la djon djuno ro jetnu du'u makau viska makau
#
#or more commonly:
#
# la djon djuno le du'u makau viska makau
#
#where {le} is used by the speaker to select the true answers.

Hmm. Okay. So "la djon djuno le du'u ma kau viska ma kau" doesn't mean
djon knows who didn't see who.

#>I take it that you object to "la djon djuno ro du'u ma kau viska
#>ma kau" on the grounds that although John knows that nobody but
#>Anne or Bill saw or was seen, he does not have in mind the
#>specific idea that Jane did not see Alice?
#
#No, I object because {lo'i du'u makau viska makau} must include
#false answers as members, which John can't very well know.

Okay.

#Also, your EC3 requires not only that John knows all true answers,
#but also that he knows that those are all the true answers that
#there are. That's probably stronger than most readings of English
#"John knows who saw who".

I don't know if it's stronger than most, but I don't think it's
at all an usual reading. "John knows who played in the 1966 World
Cup final" -- of the various readings, the likeliest is that he
knows all the players and that nobody else but them played.

#>II. Jorge's Set-of-Answers analysis of qkau does not handle well
#>all main readings of English indirect questions but has the virtue
#>of giving compositional semantics to an established construction.
#
#Could you remind me which case is not handled well?

When I said that I was thinking of Scenarios 2 and 3, but you've
now shown me that Scenario 2 is handled okay. Ragarding Scenario
3, you offered:

#SA3b. la djon djuno tu'odu'u ri djuno ro jetnu du'u makau viska makau

but I think you will agree that there is an intensional (and probably
also truthconditional) difference between John knowing that nobody but
Bill went, and, on the other hand, John knowing that for every
goer he knows that they went. So SA3 is still not satisfactory.

I suppose you could say say that "nobody but Bill went" and 
"Bill saw Jane and Jane saw Bill and nobody else saw anybody else"
each count as members as the set of answer, and in that case you
would have a way of accommodating SA3 (in terms of knowing every
true answer), but would not have a way of distinguishing Scenario 2
from Scenario 3.

--And.