Linas Vepstas wrote:
On Sun, Oct 07, 2007 at 12:36:10PM -0700, Charles D Hixson wrote:
Edward W. Porter wrote:
Fred is a human
Fred is an animal
You REALLY can't do good reasoning using formal logic in natural
language...at least in English. That's why the invention of symbolic
logic was so important.
I suppose this was pounded to death in the rest of the thread,
(which I haven't read) but still: syllogistic reasoning does occur
in hypothesis formation, and thus, learning:
-- maybe humans are animals? What evidence do I have to support this?
-- maybe animals are human? Can that be?
If Fred has an artificial heart, then perhaps he isn't simply
just a special case of an animal.
If some pig has human organs in it, then perhaps its an animal that
is human.
Neither syllogistic deduction is purely false in the real world;
there is an "it depends" aspect to it. learning AI would chalk it
up as a "maybe", and see is this reasoning leads anywhere. I beleive
Pei Wang's NARS system tries to do this; it seems more structured
than the "fuzzy logic" type approaches that antedate it.
--linas
For me the sticking point was that we were informed that we didn't know
anything about anything outside of the framework presented. We didn't
know what a Fred was, or what a human was, or what an animal was. A
Fred could be a audio frequency of 440 Hz for all we knew. And telling
us that he was a human didn't rule that out, because we didn't know what
a human was either.
Your extension questions make sense if we aren't dealing with a tabula
rasa. But we were explicitly told that we were, so the answers to your
questions would have been ??? and none and ??? and no evidence.
Your hypothetical extensions are also only considerable in the context
of extensive knowledge that was specified as unknown.
OTOH, the context was really about NARS. (I feel that my objections
still apply, but not as strongly. If I had understood what was being
discussed as well then as I do now, I would have commented less strongly.)
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