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

[pycyn@aol.com]

In a message dated 10/9/2001 9:07:53 AM Central Daylight Time, arosta@uclan.ac.uk writes:

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. Without this ability, many claims we would
want to make about what others believe would be stronger than we would
want, and also subject to other problems that we would often want to
avoid (notably, what counts as sufficient fidelity, when a bridi represents a
belief?). We need both intensional and extensional descriptions of beliefs.

Actually, we need something different from either, narrower that extensional, broader than intensional.  Extensional lets in everything that happens to be coextensive with what you want on this world, including all the things wanted but also an indeterminate amount of junk -- even vyapti lets in all the stuff that happens to fit the same s-t coordinates, so allows in a lot of irrelevant microscopic and atomic stuff.  Intensions on the other hand deal with only definitional equivalence,as it were, not the incidentals of this life that might be allowed to count in some cases of knowing, say.  (Incidentally, the "not either p or q" - "both not p and not q" passes the intensional test as well as the extensional.).

One of the initial advantages of set-of-answers theory (my version, I think not xorxes' completely) is that it provides for this middle ground in the notion of an answer to the question.  This advantage dims somewhat if you then try to unpack that notion in rigorous categories, for it is inherently pragmatic and Gricean, depending upon the background knowledge of all involved, the presuppositions of the speaker and probably the listener (to a lesser extent), and some operational notion of epistemic imperatives as appled to the particular case (is this where knowing a=b and Fa means you ought to know Fb?).  Still, it does meet the purpose and some unpacking can be done in aprticular cases at elast. So, that is some progress from the dead ends of pure extension and pure intension, which are doomed to empirical failure.