X-Message-Number: 11747
Date: Fri, 14 May 1999 11:31:56 +0000
From: Damien Broderick <>
Subject: Re: the two doubting Thomases

At 05:00 AM 13/05/99 -0400, Thomas Donaldson wrote in response to Crevier's:

===

>And if you believe that a sequential computer might emulate a human
>brain (or even the brain of an octopus) then you need to think on that
>problem a good deal more.

Frankly I have no opinion on that.
A sequential computer can simulate any parallel machine, so there is no
fundamental distinction between the two, except for speed. But this is a 
relatively minor point. Why you insist on it so much?
===

>Daniel Crevier asks why I insist on parallel computers. My reasons are
>simple: any computer that must deal with the real world will have to be
>quite fast, faster than any existing or foreseen sequential processor. It
>is just not enough to be a Turing machine: the data will come much to
>fast for a classical Turing machine, and too fast for a sequential 
>machine.

As far as I can tell, this comes down to processor speed.  Hence, I take it
that Thomas misunderstands Daniel's puzzlement; Daniel says, One can in
principle emulate the other; Thomas says, Not in the real world, buddy.
Since nobody plans to return as a Turing Machine, what salience does this
debate have?

But look: the ratio between speed of nerve impulses and the speed of light
is roughly 1: 5 million.  The size scale of nerve cells and synapses to
plausible nano components is even more striking, at least 1: 1 billion.
The switching time of current experimental lab processors, as I cited
recently, is of the order of a few hundred femtoseconds. Unless the human
brain works by non-local magic, I think one *could* emulate its functioning
on a sequential device built by principles we can already get a hold on, at
least in imagination.  But why would anyone do this?  The debate strikes me
as a thought experiment run feral.


Thomas Nord wrote: 

>it is a simple comparison to start with, as at least folks over here
>understand, with Cryonics we stand a chance better than Jesus to return as
>he haven't for almost 2000 years; Is that not a correct logic observation?

Sigh.  Yes, and David has shown carefully (if testily) why logic has
nothing to do with the damage of using a meme so offensive to so many
potential cryonics customers. (I might have slipped into the same dumb
error by including a long passionate rant about the evils of `reductive
holism' in my recent book about extended longevity.  It was perhaps
self-indulgent preaching to the converted, yet I wanted my book also to
reach those *not yet converted*.

>do you David as I guess is a man of the bible, have any better PR ideas for
>USA, or EU where I am working mainly?

David's religious affiliations have *nothing* to do with the validity of
his case.  (I would guess that he's as godless as many of us here.)  And
the difficulty of finding a powerful and effective PR idea should not
prevent anyone from shooting down one that is undoubtedly going to alienate
and enrage a vast number of the potential readership.  By the way, the fact
that your site is in Europe rather than the USA (or the UK or even
Australia) is irrelevant, unless it's only in Swedish; the net is global,
but still very heavily American in its reach and use.  We ignore these
demographics at our perils.

Just my 2 (Oz) cents.

Damien Broderick

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