

Plastination versus Cryonics - monort
http://www.gwern.net/plastination

======
Udo
_> current plastination techniques sufficing to create connectomes, but what
does it miss?_

I'm not worried about neurotransmitter levels or electrical activity, there
are enough events during a normal lifetime where these can be severely
compromised without any long term effects. What I am worried about, though, is
the fine structure of "custom" proteins - meaning proteins that have been
specifically generated by the brain to modulate the activity of one or more
very specific neurons. It's not unreasonable to suspect that these serve an
important role in long term memory formation and function.

I strongly suspect digitizing the connectome by itself may not be enough in
the same way that saving the structure of an artificial neural network
_without_ preserving info about any weights, activation functions, and other
parameters is not enough to reproduce the network later.

 _> by copying the digital data to many archives and formats online and
offline. No such option is available to a cryonics brain unless it abandons
cryonics entirely_

How you judge this depends on what you're trying to achieve with cryonics. In
theory, a destructive scan of a cryo-preserved brain should yield more and
better data than that of a plastinated one. The question becomes: do we need
that additional data or not?

I'd like cryonics to preserve brains until it becomes clear how to scan them
adequately. By comparison, cryonic preservation is a relatively gentle
process, whereas plastination imposes some heavy chemical changes on the brain
to the point where it's entirely likely that too much information could be
lost. The promise of cryonics lies not in a biological resurrection at a later
date, but in giving researchers enough time to figure out how to actually do
an upload. It _may_ well turn out that plastinated remains are a sufficient
data source, but contrast that with cryonics where much fewer doubts about the
preservation of the necessary information exist.

Of course, cryonics is beyond problematic - it requires constant and costly
upkeep. And more importantly, just a few days of political, economical, or
technological instability can easily wipe out every cryo-preserved brain in
existence. So it's clear this can't be a solution for the next few hundreds or
years. It's a solution for the next few decades at best (until the first
provider goes bankrupt).

The options, in a word, all suck.

~~~
Neslit
>cryonics [has] much fewer doubts about the preservation of the necessary
information

Could you say why you think this? Were you convinced by the experiments done
by the Cryonics Institute or Alcor? I haven't been able to contact a
disinterested neuroscientist willing to take a serious look at that research.

>just a few days of political, economical, or technological instability can
easily wipe out every cryo-preserved brain in existence

Political, maybe, if the the legal status of patients changes so that they are
required to be thawed. But why economical or technological? I think I read
somewhere that it would take like a month or something for the liquid nitrogen
to evaporate enough for the patients to thaw.

~~~
Udo
_> Could you say why you think this?_

During my time as a medical research minion I did some work on preserving
tissue samples and even whole organs, including plastination and similar resin
casts. What you need to be aware of is that, while the finished specimen look
very good and life-like, they are radically altered on a biochemical level.
All the water and lipids get replaced by resin. That requires soaking them in
formaldehyde, acetone, and other chemicals before resin can even be applied.
This process absolutely destroys proteins, in fact it relies on that. Also,
the whole process takes days to complete, and during that time bio matter is
actually being washed out and the whole structure is in motion. There is
absolutely no question that information is lost here, in droves. If you
believe plastination has a decent chance of preserving people's minds, you're
operating under the assumption that the connectome itself will yield enough
data for an upload.

Compared to that, freezing is, well freezing. Molecular motion almost ceases,
so the most important aspect to gauge information loss in cryonics is what
happens to the brain until it's finally cooled down. There are three main
problems here. The first is the formation and shape of ice crystals which can
(and do) destroy cells. This is a bit more relevant to in-vivo reanimation
enthusiasts, because the physical shearing should probably be algorithmically
correctable in a scan scenario. The second is the effect of the cryo fluid
they pump into patients to prevent said ice crystals from forming, because
it's also toxic to proteins. It's not as invasive as plastination, but it's
still pretty bad. The third aspect is the time span from asystole to the
halting of information loss. This might be a problem, but since current
research indicates that a lot of ischemic brain damage is actually a cascade
triggered by re-perfusion, there is cause for the assumption that anything up
to a few hours might actually be fine.

 _> Were you convinced by the experiments done by the Cryonics Institute or
Alcor?_

I have to admit to only a passing knowledge of their in-house research
efforts. Alcor's that is, I know next to nothing about CI. The problem is,
they - nor anyone else for that matter - are not in a position to make any
substantive claims about information fidelity _beyond_ the continuing efforts
to preserve the brain as faithfully as possible. A lot of their statements
seem to focus on future viability of the tissue, and options for biological
reanimation - but these are things I have no interest in (because I think it's
both unrealistic and a bad deal). In fact, the last time I visited Alcor's
site I couldn't find any reference to uploading at all, maybe I just missed it
though.

 _> Political, maybe, if the the legal status of patients changes so that they
are required to be thawed._

Yes, I agree. It's a massive taboo, ask any random person on the street and
they'll be horrified. It's not difficult to imagine neuropreservation might
get outlawed as soon as it looks like it might actually be feasible. In fact,
we're seeing the same thing happening now with AGI. One can only imagine the
public outcry involving bringing conserved brains back to life will be
magnitudes larger than whatever will happen in respect to AGI soon.

 _> But why economical or technological?_

By definition, cryonics companies have to operate on the fringe. That makes
them especially vulnerable to disruption from relatively minor events. But
even if they were as stable as, say a major bank: well, those fail, too. And
if they're not going bankrupt, one might imagine a power outage lasting for
months. Or some other infrastructure catastrophe that results in these
companies being unable or unwilling to maintain services. Us western countries
are kind of operating under the assumption that we're stable and eternal,
which is an illusion.

That's why I said it's a solution for the next decades at best. During that
time, if we really want to put resources behind it, we could theoretically
figure out a destructive scanning -> uploading workflow (simulation can come
later in principle). But if we're talking about biological reanimation...
there is not even a tenuous time frame imaginable. We could easily talk
hundreds of years until our nano tech is sufficiently advanced. And that's too
long for two fragile companies to keep afloat in the face of economic crises,
religious and cultural disapproval, incompetence and malice, accidents,
disasters, and world events - any single one of which can wipe everything out.

~~~
Neslit
Thanks for the detailed answer.

>If you believe plastination has a decent chance of preserving people's minds,
you're operating under the assumption that the connectome itself will yield
enough data for an upload.

Ok I think this makes sense. I doubt that the connectome is sufficient.

>A lot of their statements seem to focus on future viability...

IIRC they talk about uploading issues under the code word "information-
theoretic criterion of death", meaning that a preserved brain could be totally
non-viable while still containing enough information to be uploaded; you're
only dead if that information is destroyed, i.e. irretrievable "in principle"
to an observer with full knowledge of human neurobiology and perfect scanning
technology.

>future viability of the tissue, and options for biological reanimation - but
these are things I have no interest in

Agree, I'm not particularly worried about viability. Side note: it is a lot
easier to pitch reanimation than uploading to most people (not that it's easy
either way).

>One can only imagine the public outcry involving bringing conserved brains
back to life will be magnitudes larger than whatever will happen in respect to
AGI soon

This being mildly hilarious, because the risks from non-human strong AGI are
way way larger than those from reanimated humans or even uploads...

>But even if they were as stable as, say a major bank: well, those fail, too.

This isn't clear to me. Cryonics companies have a totally different business
plan from banks. Each customer pays a large fixed cost up front before
services are rendered, creating an endowment thing that should pay for them
indefinitely. Specifically, they could make very conservative investments,
such that it would take a world collapse to drive them under. In theory.

>hundreds of years until our nano tech is sufficiently advanced.

Hmmm... I think I would be pretty surprised if it took an unregulated nanotech
industry more than 50--100 years to develop near-arbitrary capabilities. The
roadblock to biological reanimation would be knowing what to specify to build,
not the building part. (I agree that intuitively, scanning, if not actual
uploading, should be much easier.)

>And that's too long for two fragile companies to keep afloat in the face of
economic crises, religious and cultural disapproval, incompetence and malice,
accidents, disasters, and world events - any single one of which can wipe
everything out.

This is a pretty complicated question, but how do you think each of these risk
factors would respond to broader adoption of cryonics? My guesses:

economic crises: significantly mitigated, because of economies of scale making
it cheaper and overall scale making companies less vulnerable to variance.
E.g. cryonics companies could build their own liquid nitrogen condensation
plants, which are not that expensive at scale, I believe.

incompetence and malice: similar---at scale, companies could afford to defend
against these

religious and cultural disapproval: unclear to me; how much of a threat would
this be, and how hard would it be to get people to come around?

accidents: not much to do about this. Hypothetically, with extremely wide
adoption of cryonics, there could be safety policy decisions made based on the
calculation "How many accidents leading to non-cryopreservable brains will
this lead to?".

disasters and world events: no help here. At scale, could slightly defend
against tamer disasters with underground bunkers or something.

~~~
Udo
> _" information-theoretic criterion of death"_

To be fair, this applies to any type of preservation/reanimation scenario.

> _Specifically, they could make very conservative investments_

As you said, in theory. In theory, so could banks ;)

> _The roadblock to biological reanimation would be knowing what to specify to
> build, not the building part._

Exactly. Well, speaking from today's perspective, it's both. But yes, how to
repair it and keep it alive would be a huge hassle, not to mention we simply
don't have anything approaching this capability yet, even in principle. Not to
forget, that at the end of this really long road, the problem has just been
deferred by a few decades ;)

> _but how do you think each of these risk factors would respond to broader
> adoption of cryonics?_

No, I was talking about the other way around, since cryonics is not yet a
factor in anything, it's susceptible to everything that may happen externally!
We might disagree about the weight and probability of individual events, but I
think we're clear on the fact that for quite a bit of time to come, cryonics
is a vulnerable storage facility critically dependent on the infrastructure
and benevolent indifference of our civilization - and not a concept that
changes the course of anything (yet).

~~~
Neslit
>we're clear on the fact that for quite a bit of time to come, cryonics is a
vulnerable storage facility critically dependent on the infrastructure and
benevolent indifference of our civilization

Right, I agree. I was wondering about evaluating the potential business or
philanthropic benefits of interventions on cryonics; e.g. funding research on
effectiveness of current protocols or on developing better protocols, seeding
larger operations and capturing economies of scale, advertising/PR, lobbying
for rights, etc. I haven't properly thought this through at all, but I suspect
that there might actually be a pretty good philanthropic argument for some
kind of preservation.

Society could save big on healthcare (not to mention the disutility of being
kept alive to the bitter end) by preserving anyone whose health is in severe
decline; anyone who has brain cancer, Alzheimer's, Parkinson's, etc.; anyone
with imminently terminal diseases; and so on, all voluntarily of course. I
believe end-of-life healthcare can typically cost tens of thousands of
dollars, which is commensurate with preservation costs.

Further, it seems like I'd much rather save one person to live a long life (at
the very least, thousands of years), than save two lives to live a standard
life of ~50 more years. Though admittedly this depends on what you think your
terminal values are, and also on difficult-to-estimate effects, e.g. the
instrumental benefits of having more people alive now to help with morale or
with doing stuff. And for obvious reasons this is uncomfortable to have to
consider, and even more uncomfortable to actually propose as philanthropic
policy.

------
geographomics
Preserving the connectome is probably insufficient for full restoration. Even
if you could record the entire structure of the brain at the synaptic level,
you're still missing the functional states of the neurons and glial cells that
it is composed of. It would be like trying to reconstruct a piece of software
solely from its call graph.

------
davidrusu
It's important to realize cryonics/plastination research is not just for
people who want to extend their lives. It's going to be a crucial component in
long term space flight.

~~~
listic
I am not convinced that long term space flight will be really interesting, at
least _before_ we radically extend our lifespan (you mean interstellar,
right?). The space is just too big.

~~~
Symmetry
A Hohmann transfer even to Neptune is 40 years. In practice I'd expect it
would be more like a decade using less efficient orbits but I hope that shows
that even within the solar system there can be trips long enough that
suspension would be an asset.

------
anti-shill
preserving information is key...if plastination preserves memory, it is
worthwhile.

