From: Robert J. Bradbury (bradbury@aeiveos.com)
Date: Wed Aug 28 2002 - 10:03:01 MDT
(Terry, please forward this to the list from which the message came,
I can't tell what that might be from the message.)
On Tue, 27 Aug 2002, Terry W. Colvin wrote:
> Driven FromThePack wrote:
>
> Not quite... If I could precisely describe the complete "wiring scheme" of
> your brain and store it in a buch of CDs, those CDs wouldn't be you. You
> need more than the information -- you need the brain too.
One doesn't need a "brain". One needs sufficient computational capacity
and an architecture that can function like a brain. One could reanimate
a person given the information contained in a brain on a molecular dynamics
simulation of all of the atoms in a brain. Mind you it requires a solar
system sized computer and the power output of the sun to do this using
any near term technologies, but those are merely details.
> And even though I could right now specify the connections between a million
> neurons (e.g. a cube of 1000x1000x1000 with all neighbours connected) no
> one could make such a neuronal circuit. So what you really need is to
> recover the brain with little damage.
No you don't. One perfectly reasonable cryonic reanimation scenario
involves a destructive, slice by slice, readout of your information content
using for example AFM's scanning the synaptic connections at the molecular level.
So long as you can get the information out and recreate it in a form that
functions equivalently, *you're* not dead.
> But you ommit here the "information loss" (i.e. brain damage) associated
> with the freezing process. Evidence indicates that this is considerable
> with current or forseeable techniques. We can't even freeze a kidney, let
> alone a brain...
Actually, the kidney is a bad example because it is a highly structured
organ. Brains are probably going to be easier to freeze and restore
than kidneys.
What most people fail to realize is that synaptic connections are micron
sized structures that are fixed in place with essentially molecular velcro.
*Even* if freezing were to tear those apart, there would remain a molecular
fingerprint of where the synapse was once attached. There are going to
be millions to billions of atoms on each side of a synapse, axon or
dendrite that might be severed by the freezing process. For cryonics
not to work one needs to make a very strong assertion that there is
information loss in the freezing process that cannot be recovered.
The only way I can see that happening is if you force the brain through
a spaghetti colander.
> And once the information is lost, even developing a thawing process that is
> 100% efficient and looses no information at all, you'll still have a badly
> damaged brain. Remember that your brain will be frozen after you die, and
> unlike other tissues which can survive for significant periods (hours or
> more) with no oxigen, brain damage becomes irreversible after a couple of
> minutes.
Actually, I believe 21st Century Medicine has demonstrated the
ability to stop blood flow to the brains of dogs and reanimate
them after more than 15 minutes. It isn't actually the lack
of oxygen that is the problem so much as the free radical damage
that results when you restore oxygen to the tissue.
> Science is based on evidence. Evidence indicates that freezing your brain
> will destroy it, if it's not already too badly damaged even before the
> procedure starts (do they guarantee they'll start freezing within a minute
> of your heart stopping?).
The "evidence" indicates that freezing a brain *damages* it, not that it
"destroy's it". The fact I can freeze a steak, thaw it out and what I
get back is still largely a functional steak argues that freezing does not
fundamentally destroy tissues.
Until the molecular velcro holding the synapses together is degraded
and/or the axons and dendrites are destroyed (a process that takes hours
if not days) one still has the information content of the brain.
> My conclusion is thus that cryopreservation of human brains is not science
> but misguided faith and quackery.
> Ludwig Krippahl
What I know for certain is this. Being incinerated quickly destroys
the information content of the brain. Being buried more slowly
destroys the information content of the brain (presumably the
molecules making up the connections are eventually consumed by
bacteria). Being frozen is the best of the three options for
preserving the information content in the brain such that it may
be recovered (or restored) at some future date.
It isn't "faith" which by definition rests on no evidence at all.
(I can cite the steak example as evidence that freezing something
does not "destroy" it.) It is also not "quackery" since this is
essentially a bet based on reasonable projections of technology
developments based on historical trends (e.g. Moore's Law) and
authoritative and informed opinions (e.g. Feynman, Drexler, Merkle, etc.).
Robert Bradbury
[bradbury@aeiveos.com]
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