Path: utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!uunet!decwrl!shelby!csli!weyand
From: weyand@csli.Stanford.EDU (Chris Weyand)
Newsgroups: comp.ai
Subject: Re: simulating brains
Message-ID: <15631@csli.Stanford.EDU>
Date: 3 Oct 90 06:10:40 GMT
References: <1990Oct2.221006.3024@csc.anu.oz.au>
Organization: Center for the Study of Language and Information, Stanford U.
Lines: 34

In <1990Oct2.221006.3024@csc.anu.oz.au> ada612@csc.anu.oz.au writes:

>The sense of my final parenthesis is that I find the standard idealizations
>of computability theory to be a very dubious framework for thinking
>about brains.  Computability theory is about what can be done eventually,
>whereas brains have to keep up with the real world, always providing some
>sort of output in response to the current input.

So don't use computatbility theory.  I mean there really is a difference
between computers such as the MacIIcx I'm using right now and Turing Machines.
The main one being that TM's can't be fitted with an array of sensors and
effectors or anything else physical since they themselves are not.  Also, sure
computatbility theory talks about what functions can be computed and is not
concerned with time or space efficiency.  But we who program real computers
are very concerned with those issues.  Just because the theory says little
about efficiency doesn't mean that computations can't be done efficiently.

>Consider for example the following basis, which seems to be fairly widely
>accepted, for believing that a computer or robot is sentient:  if it looks
>like a brain (at the relevant level of structure) and acts like a brain,
>it should be presumed to be/have a mind.  But  `fixed horsepower'
>computing devices will neither look nor act like brains.  In Searlespeak,
>one might say that their causal powers differ from those of brains in a
>non-mystical and functionally relevant way.  So why suspect them of sentience?

You can't disprove a statement X by simply saying X is not true!

I think a better test of sentience would be if it acts like a mind then
it may be presumed to be a mind.  Acting like a brain presumably involves
sending chemical/electrical signals here and there and that doesn't sound
very interesting.  After all the brain of a frog acts like a brain.

Chris Weyand
weyand@cs.uoregon.edu -=- weyand@csli.stanford.edu