X-Message-Number: 8549
From: Thomas Donaldson <>
Subject: Re: CryoNet #8533 - #8540
Date: Sat, 6 Sep 1997 12:15:27 -0700 (PDT)

Hi again!

I got lots to do so I'll try and be brief.

1. On Turing Machines: I'm glad that John Pietrzak has given us the detailed
   definition. 

   My problem with the definition is NOT that it is wrong in any way, but
   that for many practical uses it is incomplete. (Definitions can't be 
   wrong!). That is where parallel computers come into the picture. Sure,
   you will have an "equivalent" machine if you have a sequential Turing
   machine, but the weight falls on that notion of "equivalence". The
   answers would be the same, but they would not some as fast. To many people
   that's damned important. So for PRACTICAL purposes, it's useful to think
   about more restrictive definitions.

   Anyone with even a little mathematics will know that "equivalence" can
   be defined in many different ways, as you wish. Turing Machines are 
   certainly equivalent to parallel machines if equivalence means that their
   results are the same. If equivalence means that their results are the 
   same AND are attained in times within an order of magnitude of one another,
   they are not equivalent.

2. On LN2 and deterioration at LN2 temperatures: it is flatly false that 
   you're going to get much deterioration over humanly short times like
   1000 years or so. The chemical reactions go too slowly. 

   On uploading: As I've said, I have no problems with uploading if it is
   for storage. The means for reading off brain structure you describe 
   are speculative: I believe that someday we'll be able to do this, by some
   means, but don't see that as a LONG TERM problem. Unfortunately, we must
   deal NOW with the short term. If you are lying there with no heartbeat
   or breathing, do you really want us to first develop means to read off
   your brain and then upload you into a computer? Not only that, but one
   of the means you suggest involves destroying the brain. While that may
   work, it really puts a big load on how accurate your readout may be. This
   is a PRACTICAL problem.

   I do have problems with uploading if I am to be "alive" in the computer.
   A lot depends, of course, on just what is meant by a computer. As I've
   pointed out, a Turing machine won't necessarily qualify for practical
   reasons. Moreover, we really do process things differently than present
   computers. To copy that, we must first understand just what we do in
   more detail than presently known. Since we are quite parallel ourselves,
   whatever we are uploaded into should also be at least as parallel. 

   A few issue of PERIASTRON back, I had a little editorial about Ptolemaic
   science. It concerned M. Minsky's book of speculations about how our brain
   worked. Minsky is hardly a stupid person, but in terms of understanding
   how REAL brains work his book suffers from a lack of any correspondence
   with experiment on real brains. We want to understand how brains work,
   not just have speculations about it based on what we know of comput
   We're going to have to get our hands dirty.

   Most of all, experiments on brains are needed because even the most 
   imaginative among us may have failed to imagine just how we work. Even
   a little thought about real brains should convince most people that
   they don't work like computers. It's not enough just to imagine SOME
   way in which they MIGHT work. We want to know how they DO work.
   
   Frankly, by the time someone who has been damaged both by freezing and
   treatment before and during "death" is finally revived, I believe even the
   notion of "computer" will have gone through so many changes that we can
   forget about our contemporary machines in thinking about this issue. 
   Are brains computers? Are very much improved brains computers? For that
   matter, biotechnology already has a richness to it that dwarfs present
   nanotechnology of other kinds. I suspect those who want to come back
   uploaded into a computer think of them as mythical entities capable
   of many different things impossible otherwise. Heck, they're not 
   BIOLOGICAL. (No snot, no sweat, all those other things ...). Yet many
   biological things (emotions, perhaps?) we want to retain; and as for
   wastes and being subject to various attacks by other creatures, computers
   have even now begun to be attacked. Wastes, of course, will always be
   with us. Is it better to shit out used semiconductors or used biological
   waste? You tell me.

No doubt some will think of various replies. Sorry, but I have to stop now
and do some other things. Naturally I'll come back later. I have to deal with
my biology, too.

			Long long life,

				Thomas Donaldson

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