[comp.ai.digest] the human mind as a logical system

NICK@AI.AI.MIT.EDU (Nick Papadakis) (06/02/88)

Date: Fri, 27 May 88 21:04 EDT
From: Antti Ylikoski <ayl%hutds.hut.fi%FINGATE.BITNET@MITVMA.MIT.EDU>
To: AIList@AI.AI.MIT.EDU
Subject: the human mind as a logical system
cc: ayl@hutds.hut.fi

It would seem that the human mind is very fault-tolerant with respect
to locigal oddities.

Example: a human being can be a queer reasoner in the sense of
Smullyan.

I recall that a queer reasoner believes a proposition p (Bp) and
simultaneously believes he/she doesn's believe p (B - (Bp)), the minus
sign denoting logical negation.

Let John be a true believer of some obscure faith.  Say the Tur
religion by Edgar R. Burroughs in his Tarzan books.

Let p be the proposition "Tur exists".

Let John lament his lack of faith to a Tur priest.

Then John believes in Tur (Bp) but believes he doesn't believe in Tur
(B - (Bp)).

Andy Ylikoski