From newshub.ccs.yorku.ca!ists!helios.physics.utoronto.ca!news-server.ecf!utgpu!cs.utexas.edu!uunet!bcstec!ray Tue Nov 19 11:09:05 EST 1991
Article 1205 of comp.ai.philosophy:
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>From: ray@bcstec.boeing.com (Ray Allis)
Newsgroups: sci.philosophy.tech,comp.ai.philosophy
Subject: Re: Is there any such thing as informal logic?
Message-ID: <1455@bcstec.boeing.com>
Date: 5 Nov 91 23:02:31 GMT
References: <1991Oct22.041210.5931@watserv1.waterloo.edu> <JMC.91Nov2175822@SAIL.Stanford.EDU> <1991Nov3.031516.5007@husc3.harvard.edu>
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[John McCarthy & Mikhail Zeleny debate at length...]

This debate has missed the point completely, again.

Of course there is no such thing as informal logic.

The phrase "informal logic" is analogous to the phrase "illegal law".

In the little example puzzle, the words "missionaries" and "cannibals"
are just place-holders upon which to hang relationship and interaction
assertions.  The form of the structure would not change if we used
other place-holders, such as "rats and grain", "unicorns and cat fleas"
or "red beach balls and empty tomato juice cans".

The missionaries & cannibals argument is form-al; it is about form, not
content.  Content is carefully and deliberately removed.  Logic is
about form; the word "formal" in "formal logic" is redundant.

Logic is the easy part (only part!) of human thought.  For 2000+ years
people have been trying to develop a calculus (or algebra) of thought,
and leaving the harder parts, such as analogy and induction, for
later.

This is the situation with Artificial Intelligence.  AI is said to be a
sub-discipline of Computer Science.  Digital computers are logic
machines.  AI, therefore, is to be accomplished with logic.

It is the notion that logic is sufficient to duplicate human thinking
which leads to silly efforts (computational linguistics, machine
translation) attempting to treat human language as if meanings were
computable.

Extending various logics only helps the logical part of intelligence,
it is induction and analogy that need attention.  Accept that fact that
important parts of human thought deal not with form, but content.
Figure out how to generate statements such as "Life is like a river".
Quit avoiding the hard problems.

Ray Allis


