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From: andrew@cee.hw.ac.uk (Andrew Dinn)
Subject: Re: Does AI make philosophy obsolete?
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Date: Tue, 3 Oct 1995 09:46:25 GMT
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Ron Hardin <9289-11216> 0112110 (rhh@research.att.com) wrote:
: John McCarthy writes:

: >Can you build a BDD with quantified sentences?  What about function
: >symbols?  What about modal operators?  What about formalized contexts?
: >What about nonmonotonic reasoning?

: I don't know what nonmonotonic reasoning is, but have the feeling it
: must wear the pants.  BDDs like quantification, enjoy it more than
: anything.  There is even a call bdd_unify() that does God knows what.

Nonmonotonic reasoning is that arguably artificial and unintelligent
(although most rhetoricians would disagree with me here) trick of
reasoning where you shift premises to find better accommodation for
the vending of your conclusions. It's one of the things dedicated (and
dirty) Lisp and Prolog hackers proudly proclaim as justification for
using dirty tricks while more pure-hearted logic and functional
programmers look on with disdain.

: You'd do the missionary problem by iterating BDDs.  Except for the
: island case, they're all formal verification problems, and
: can be written and solved directly.  Verify that the other bank
: is not reached, and the error track is the solution.

: This comes to enumerating every possibility.  BDDs do it
: mechanically but efficiently, without a trace of reasoning.

yes but as John is pointing out its not always a question of
verification. Sometimes out reasoning progresses by invalidating that
which we have verified.


Andrew Dinn
-----------
Daran, nachdem die Wasserwogen / Von unsrer Suendflut sich verzogen
Der allerschoenste Regenbogen / Als Gottes Gnadenzeichen steht!

Geopolitical truth is like a hedgehog.  It doesn't know much, but it
knows one big thing.  And here is the power of geopolitics properly
applied.  It is robust in perspective, admittedly partial, always
incomplete, schematic even, and at times fanatic.  In the end it
unifies and clarifies, and imposes on complex reality its imperatives,
to plan and to act. -- General Golbery do Couto e Silva, 1957
