[extropy-chat] Cryonics and uploading

[Robert Bradbury]

On 2/1/06, Michael Lawrence <Michael at videosonics.com> wrote:

> > Ok, so what about children who have been revived after hours of being
> > submerged in near freezing water?  They have no circulation and no
> > brain activity when they are pulled from the water.  They experienced
> > death, but then are revived, apparently undamaged.
>
> My understanding is that 'brain death' is irreversable, and so there would
> have still been "brain activity" on some level.


Michael, "brain death" is an arbitrary term currently used in medicine.  I'm
sure there are relatively precise technical definitions but they usually
involve a lack of detectable electrical activity and a failure to respond to
stimuli (which is what one would expect given a lack of electrical
activity).  It also implies, particularly when it gets into whether or not
one is "legally" dead, the assumption that no *current* technology is
capable of "resurrecting" the brain.  But cryonic suspension is not resting
upon the assumption of current technology.  It assumes we will develop
better technologies in the future which will correct both the cause(s) of
death as well as the damage(s) associated with suspension and reanimation.

There was a recent discussion of the technical aspects of this on the GRG
list citing a number of studies where the heart was stopped and various
fluids (presumably non-oxygenated and lacking glucose) were circulated
through animals and the animals were able to survive a minimum of 3.5 hours
without "brain activity".  There was a technical discussion regarding the
degree to which biochemical activities may slow down given various
temperature reductions and the problem of the damage that may result when
"resurrection" is attempted.

The bottom line (IMO) is that the individual is not "dead" until the
information content of their brain is disassembled (incineration or
bacterial molecular recycling probably being the most efficient methods) in
such a way that reassembly would require capabilities beyond currently known
laws of physics to return them to an operational state.  Current brain death
perspectives involve (a) a loss of activity which can be due to a loss of
energy supplies (O2 & glucose); (b) a loss of activity due to the poorly
managed reintroduction of energy supplies (producing free radicals which may
lead to cell death); (c) physical trauma (leading to a disruption of the
physical connections between large numbers of neurons and/or extensive cell
death).  With (a) and (b) a management of temperature to control the rate of
chemical reactions (e.g. proteases which may digest the cells internally and
the rate of free radical production are important in the degree of damage
occurs which cannot currently be repaired.  Repair of (c) would involve
near-future microsurgical and/or stem cell therapies to repair the damage
sustained to the brain structure.  There might be some information loss but
it might be no different than that sustained in strokes from which patients
often recover (the brain is an adaptable organ).

Its the *information* which is the individual -- not the instantiation or
substrate which retains it.  People may choose not to believe that, many
choosing to cling to the "man behind the curtain" set of beliefs that we are
something more than that (I even like to do so at times).  But I strongly
doubt that is something they will *ever* be able to conclusively prove.

For me "Plan a" is preserving the thread (with various levels of stopping
and restarting it [sleep, unconsciousness, "brain death", cryonic
suspension.]  "Plan b" is preserving the information [most probably via
uploading or recreation from external sources].

Robert
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