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More about questions and the like (was:What I have for dinner...")
- Subject: More about questions and the like (was:What I have for dinner...")
- From: Pycyn@aol.com
- Date: Thu, 9 Dec 1999 05:08:30 EST
The "for all x, if x went to the party then John knows that x went to the
party (perhaps with a relative completeness guarantee or something like "and
if x did not go to the party then John does not believe that x went to the
party") has to be used with care. One should not infer from it that, if Paul
went to the party, John knows that Paul went to the party, at least in the
sense that if John is asked "Did Paul go to the party?" he will say yes, even
if he is being as cooperative as possible. the problem is the intensionality
of "know," for John may not know Paul under the name "Paul" and may even know
him under the mistaken guise "Bill's father" (when he is actually Joan's
father). To be sure, the quantifier outside the context guarantees that the
generality is indifferent to the disguises, but the individual cases have no
such obvious external connection. We need either explicitly write "under
some concepty" somewhere here or flag the cases with the opposite of subject
raising (which I think Lojban has). The set-of-answers version of questions
does not work so well in this case, unless the questions are subdivided into
identity classes and all that is required is that John know at least one
member of each of the appropriate classes.
A couple pages on from this point in the Handbook of Philosophic (i.e.,
freaky) Logic is the reminder that every natural language sentence is a
dependent of a (usually unexpressed) performative, usually "I tell you that"
or some such. However, some of these performatives may also be intensional,
in which case every term in the surface sentence is in that cloud-cuckoo-land
where Leibnitz's law fails along with existential generalization and
universal instantiation. In particular, sentences mentioning non-existent
objects which are nonetheless held to be true are under performative like "I
now recite to you a bit of myth that..." This being the case (and it sure
solves a lot of problems), Lojban needs to dig into its small stock of unused
cmavo for a flag of this sort for when context is not enough. Remembering
that the term-length flag of this sort is something like tu'a, I suggest the
corresponding x form, xu'a. this refers to a different enduring problem form
ages past.
pc