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Article 5519 of comp.ai.philosophy:
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>From: wcalvin@hardy.u.washington.edu (William Calvin)
Newsgroups: comp.ai.philosophy
Subject: Re: brains and information processing
Message-ID: <1992May9.231318.16958@u.washington.edu>
Date: 9 May 92 23:13:18 GMT
References: <1992May6.205923.14479@organpipe.uug.arizona.edu> <1992May7.164257.17225@psych.toronto.edu> <1992May7.192257.23595@organpipe.uug.arizona.edu> <1992May9.172828.17624@psych.toronto.edu>
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christo@psych.toronto.edu (Christopher Green) replies to

>>  I take it as self-evident that brains have evolved because they
>>contribute to the survival of organisms.  They contribute to
>>survival by controlling the actions of muscles and other tissues.

by saying: 
>In the case of the brain, I'm inclined to agree with you, but don't make
>the miske of thinking that just because something evolved, that is must
>therefore have contrbuted to the survival of the species. These kinds
>of just-so stories of evolution have little place in modern evolutionary
>theory. Consider, for instance, the numbers of fingers and toes we have.
>Would you argue that having five of them gives us some sort of advantage
>over creature with four or six? Apparently not, considering the number
>of creature that can kill us with a single swipe of their four-toed paws.
And:
>Function and *essential* function (the phrase you used) are two different
>things.  There nothing *essential* about this function of the brain. Moreover,
>you're going to use this definition to ground a statement of equivalence
>between the brain and computers, you've got a lot of work to do re explicating
>the ambiguous and equivocal terms you've brought into discussion, e.g.,
>"information", "signal", "process", "manipulate", etc. As you verge on pointing
>out yourself (and as Searle does about the stomach) the liver is as much
>an "information processor" as is the brain. It all depends on you construal
>of "information" and "process".

Calvin replies:
The history of evolution, for various organ systems including brains,
includes many examples of what Darwin called "functional change in
anatomical continuity."  And part of that is multiple function for brains:
 some functions are well-shaped by natural selection (color/motion vision
in primates, for example, was shaped by spotting fruit high in trees
against a background of leaves waving in the breeze).  Other functions
(e.g., reading) are clearly secondary uses little exposed to natural
selection for very long.
	I like to argue (see THE ASCENT OF MIND for the most recent
version) that most of our higher intellectual functions (language, plan
ahead, logic, music, even our many serial-order games) are simply
secondary uses of neural machinery (largely premotor and prefrontal) that
were primarily shaped initially by a particularly demanding precision
timing task, namely throwing projectiles at targets that don't give you a
second chance if you miss.  One can create "computing" capabilities from
such a base, but it looks more like darwinian evolution (as seen in the
immune response) than it does any known type of computer architecture or
hardware/software distinction.
    William H. Calvin   WCalvin@U.Washington.edu
    University of Washington  NJ-15
    Seattle, Washington 98195 FAX:1-206-720-1989


