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From: minsky@media-lab.media.mit.edu (Marvin Minsky)
Subject: Re: LOGIC AND RELATED STUFF
Message-ID: <1991Jun27.005850.1176@news.media.mit.edu>
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References: <9106190527.AA17403@lilac.berkeley.edu> <1991Jun26.152830.12273@cis.ohio-state.edu> <1991Jun26.173142.3060@watdragon.waterloo.edu>
Date: Thu, 27 Jun 1991 00:58:50 GMT

In article <1991Jun26.173142.3060@watdragon.waterloo.edu> cpshelley@violet.waterloo.edu (cameron shelley) writes:
>In article <1991Jun26.152830.12273@cis.ohio-state.edu> byland@iris.cis.ohio-state.edu (Tom Bylander) writes:
>[...]
>>I should mention that I do not believe that logic is going to solve
>>all the world's problems.  As many articles have noted, there are lots
>>of problems with logic.  However, just because logic has some problems
>>doesn't mean that logic is dispensable.  Whether we like it or not,
>>modus ponens is still something we will have to take into account.
>
>Curious you should metion modus ponens.  At the CUNY Cog. Sci. conference
>this year, there was a session given by a panel of philosophers on the
>subject of the psychological reality of some classical rules of logic.
>They gave some interesting statistics on when a group of university
>students actually performed inference in problems where it was possible.
>Modus ponens was more readily used than modus tollens, among other
>things.  However, they also gave some counter-examples to the use of
>modus ponens, which I don't presently have at hand.  Perhaps some interested
>reader can fill me in again.
>
[...]  Whatever logic does do (or model) in producing interesting
>behaviour, it doesn't appear to be enough.
>
>				Cam

I'm glad Cam mentioned this, because I was having trouble explaining
why I seemed to be so much against "logic" or "formalism" or whatever
it was, and a lot of pro-philosophical readers seemed disturbed at
this.  

  And well they might be, because perhaps what I really meant to say
was not so much that logic was bad but that the general direction of
philosophy itself may be too psychologically naive.  What Piaget
discovered, more or less, was that children of even 10 to 12 years old
are still generally both not disposed to, and apparently, not very
well able to, use any of the traditional forms of logical inference.
Nor, in fact are most adults, except when the problems are handed to
them in the simplest (unidirectional) forms.

  And yet, my friends, it is easy to lose an argument with a 10 year
old.  Or even a five-year old, when you're wrong enough.