[FoRK] Extreme Life Extension: Investing in Cryonics for the Long, Long Term

Eugen Leitl eugen at leitl.org
Wed Jun 23 03:59:44 PDT 2010


On Tue, Jun 22, 2010 at 08:50:16PM -0700, Ken Ganshirt @ Yahoo wrote:

> It's not simply a revivification issue. It's just possible 
> it may be a secondary issue. There is still the issue of 
> what killed you. No point in revival if they can't fix 
> what killed you in the first place. Otherwise what's the point of it all?

Death is a moving target. It is always stated in what
is not yet reversible at a given level of technology. See for 
instance 

	http://www.timeoutintensiva.it/archivio/cc3894.pdf?PHPSESSID=79a9b2cb47d09efdc8081c2f4e75ed07

for the current mainstream view.

In the course of an ideal suspension, you're immediately put on a more
vigorous life support than the one you've been on when you've been declared 
dead. Since you'd be likely to wake up, you're medicated with a large
number of drugs (which also blocks a number of ischemic damage pathways).

So you're not that "dead" that some people seem to think -- all assuming
an ideal suspension, which, while not the rule, does occasionally occur 
in real life.

However, after washout and cooldown (which is pretty bracing even
for a healthy animal -- a minority of experimental animals can no
longer be resuscitated at that point, and the number grows with 
each passing hour -- the absolute ceiling is probably at 24 hours
or so) you're perfused with a high molality of colligative and noncolligative
cryoprotectants. While single, healthy organs could still be recovered
at that point it does not look likely that the whole organism
can be recovered from that stage, using current technology, and
in fact any near- to mid-term technology. So they "kill" you
all right here, and the thermal descent does make it worse. Assuming
you'll be vitrified, and stored at below vitrification temperature
(basically, an electrically heated, insulated box hung in the headspace 
of a liquid nitrogen dewar) you will not see fracturing. If
you'll be stored conventionally, there's fracturing due to thermal
stress which is equivalent to multiple extremely deep slices
through e.g. muscle. If you devitrify at this point and attempt
to reperfuse you've got these deep cuts to attend.

Anyways, once you're in storage state you're good for kiloyears
of storage at least. Time has effectively stopped, everything is
locked in place and suffers no further structural degradation.

If you want to ressurrect in the flesh, you'd need nanotechnology.
A most straightforward approach would to move a zone of disassembly
and recording through your body which is at least a few microns wide, 
so you only exist in a voxel data buffer in this zone, run whatever 
digital filters and reconstruction to recreate a pristine state on the other
end (not necessarily in close vicinity, in principle you
can send the data stream anywhere you want), perhaps around a 
retractable fractal heat exchanger (that for flash-devitrification).

An even simpler approach is not to bother rebuilding the flesh
and rebooting it into a living state but to extract the information
processing system only, translate and load it into a suitable
emulation target, and present it with a whole body phantom,
within a very detailed rendering of an artificial reality.

The later approach is so much easier and cheaper (and does not,
in fact, require nanotechnology) so that I presume it will be the
preferred mode of resurrection.

First animals will be probably scanned (using fixation/staining,
and e.g. serial SEM) and resurrected as individually accurate
numerical models within the coming decade. We definitely can do
a snail well before 2020, if we want it, and we fund it. A mouse
would be mostly an issue of scaling it up. And a primate even
more so.

-- 
Eugen* Leitl <a href="http://leitl.org">leitl</a> http://leitl.org
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