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title: Plastination versus Cryonics
description: Break down survival to Drake equation, see on which terms & how plastination differs from cryonics to try to calculate overall advantage.
> "No man is an iland, intire of it selfe; every man is a peece of the Continent, a part of the maine; if a clod bee washed away by the Sea, Europe is the lesse, as well as if a Promontorie were, as well as if a Mannor of thy friends or of thine owne were; any mans death diminishes me, because I am involved in Mankinde; And therefore never send to know for whom the bell tolls; It tolls for thee...."^[[John Donne](!Wikipedia), [Meditation 17](!Wikisource "Meditation XVII")]
The [Drake equation](!Wikipedia) for [cryonics](!Wikipedia): is just a number of sequential steps with independent probabilities, all of which must succeed, none more important than the others. (One software version is the [Cryonics Calculator]( Specific equations and values have been proposed[^drake], usually yielding probability of success 0<_x_<10%.
[^drake]: For example, Steven Harris in 1989 calculated [0.2-15%]( chance, R. Mike Perry in the same article runs a different analysis to arrive at 13-77%; Robin Hanson calculated in 2009 a [~6%]( chance, Roko, [23%](; and Mike Darwin in 2011 (personal communication) put the odds at <10%.
# Equation
One such Drake equation might break out the steps as follows:
1. Likelihood of getting preserved
2. \* preservation contains needed information
3. \* information's survival over the centuries until revival possible
4. \* existence of organizations or entities arranging revival
5. \* the actual revival
With those 5 values, one multiplies to get the final probability of each step coming true and hence of a successful revival. Because each step is multiplied together with no weights, improvements are equal - an improvement in one factor is as good as the same improvement in another factor: a 10% improvement in organizational continuity is as good as a 10% improvement in the odds that the vitrification preserves necessary information, which is as good as a 10% improvement in odds that revival tech will be developed. This also holds for balancing profit and loss (it's all the same). A technology that increases the organizational parameter by 11% and decreases the information preservation parameter by 10% would be a net gain, because the 11% gain in one step outweighs the 10% loss in another, regardless of what concrete values one assigns.
# Plastination
Biological samples have been accidentally preserved from the deep past through dehydration, freezing, anoxia, and chemical preservation; [ancient DNA](!Wikipedia) has (possibly) been recovered from 250 million year old salt crystals, [23 million year old insects]( are classifiable and preserved in high fidelity, and ice samples have preserved [800,000 year old]( ([abstract]( and [400,000 year]( old DNA. 38,000 year old Neanderthal DNA has been [partially recovered & sequenced](, as has 28,000 year old [woolly mammoth]( DNA. One 4000 year old human genome was [sequenced]( Many of the samples chemically preserved in [amber](!Wikipedia) turned out to be [contaminated mistakes](!Wikipedia "Ancient DNA#Antediluvian DNA studies"), but nevertheless, the [preservation](!Wikipedia "Amber#Paleontological significance") is very good and down to [the cellular level](
> "Examination of the ultrastructure of preserved tissue in the abdomen of a fossil fly (_Mycetophilidae Diptera_) entombed in Baltic amber revealed recognizable cell organelles. Structures that corresponded to muscle fibers, nuclei, ribosomes, lipid droplets, endoplasmic reticulum, and mitochondria were identified with the transmission electron microscope. Preservation was attributed to inert dehydration as well as the presence of compounds in the original sap which functioned as natural fixatives. This evidence of cell organelles in fossilized soft tissues represent an extreme form of mummification since Baltic amber is considered to have formed about 40 million years ago."
(Even the color in dinosaur feathers has been [preserved in amber]( [Ben Best](!Wikipedia) describes amber's preservative mechanism in ["Ancient DNA & Preservation in Amber"](
> "Tree sap (resin) contains sugars as well as alcohols & aldehydes (including terpenes), which are dehydrating & antibiotic as well as providing an air-tight seal to prevent further entry of oxygen. Myrrh is a mixture of resin, gum and essential oils from the _Commiphora_ plant that was used by the ancient Egyptians for embalming (by pouring it into the cranial, chest, abdominal and pelvic cavities) and mummification (by soaking the wrapping bandages in it)....Amber, as a sticky pitch from certain trees, can trap insects when fresh from a tree-wound. The sugars, alcohols & terpene-aldehydes diffuse into the insect to dehydrate & preserve. The amber surrounds the insect, providing an air-tight seal. Further oxidation & polymerization of the terpenes protect the insect from further damage. The continued polymerization of the amber terpenes eventually results in an insoluble gemstone-quality glass that preserves the insect in a strong encasement. Although such fortuituous combination of chemical preservation and oxygen-tight encasement should not be expected for preservation of large specimens (like humans or dinosaurs), the use of some hardened plastic or resin encasement could assist chemical and/or dehydration preservation."
[Plastination](!Wikipedia) and [chemical brain preservation](!Wikipedia) have been seriously proposed^[As far as I can tell, pretty much every pro-con for plastination vs cryonics applies to chemical fixation with the exception of the lipids, so in the following I treat them as synonymous.] as an alternative to cryonics, apparently first by Charles Olson in ["A Possible Cure for Death"]( R. Mike Perry discusses it favorably in ["The Road Less Traveled: Alternatives to Cryonics"]( Greg Jordan says no convincing counter-arguments have been raised since Olson and strongly approves of it in his post ["Biostasis through chemopreservation"](
Is plastination a net gain?
## Advantages
Advantage for plastination:
1. Improves survival parameter #3: It is probable that scanning technology will outstrip upload technology. In many fields, the ability to gather data exceeds the ability to process or understand it. Hence, it is possible and quite likely that during the long wait for revival, it will become possible to scan a plastinated brain in sufficient resolution to eventually upload it.
Even if the scan were destructive, such a scan would make it possible to drastically increase survival odds 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, in which case why did it take the risk of the cryonics failing & it warming up rather than be plastinated from the beginning? It's hard to imagine the benefits being so equally balanced that the actualization of better scanning would is enough to change the plans - given how many parameters there are, a 'pure' strategy of 100% cryonics or 100% plastination will win. (Indeed, one might wonder how one *would* know that a plastination+scanning procedure was good enough for uploading in the absence of a successful human upload. Human biology often diverges from even close animal models, and shouldn't we expect things like consciousness to be even less reliably modeled by those animal models? The window between the first successful upload and widespread uploading will be short compared to the time between now and then, even if you assume no Singularity of any kind, not even Robin Hanson's [Crack of a Future Dawn](, and a slowed-down Moore's law.)
2. Improves organizational parameter #4: Plastination may be such a technology. It does not require organizational continuity; one rough year and your brain is a pile of rotting maggots with cryonics. one rough year with plastination, and your brain is a bit dusty^[Apparently it's best to store even a plasticized brain in cryogenic storage; [Jordan Sparks]( says "If they don't transition to cryopreservation, damage will be ongoing for decades."]. A plastinated brain doesn't even need an organization: it may be preserved as a time capsule, a family heirloom, a curiosity, or perhaps just buried somewhere; but a cryogenically stored brain *must* have a sophisticated support system which will supply it regularly with liquid nitrogen, and that rules out pretty much everyone but a cryonics organization. Mike Darwin has been a real wake up call - the [Outside View]( says [ALCOR](!Wikipedia "Alcor Life Extension Foundation") and [CI](!Wikipedia "Cryonics Institute") are much more risky than usually assumed[^businesses] - and indeed, one cryonics organization has [already failed]( with the loss of patients. Past the century mark, a few percent is the highly optimistic estimate! Cryonics organizations have done reasonably well, but ALCOR consistently runs at a loss and if membership does not follow an exponential growth (as it does not), then relatively soon the ratio of dead members to live members will start getting much worse.
3. Improves likelihood of preservation #1: Much cheaper than vitrification; while cryogenic storage is very cheap [in scale]( the cost is still non-trivial for the foreseeable future.
4. Improves revival parameter #5:
1. despite being a relatively young field (albeit respectable & well-funded), plastination & scanning has made tremendous progress and is slowly [being automated](, with one human brain sliced at 70 micro thickness and photographed^[The brain of the [patient "HM"](!Wikipedia "HM (patient)"), processed by [The Brain Observatory]( of UC San Diego.], or producing partial [connectomes](!Wikipedia)^[Although hopefully in ways more efficient than a few professors and technicians [laboring together]( or [yoking dozens of students](!] of brains. One might characterize the two fields as: connectome:upload::revived-rabbit-kidney:functioning-brain, and ponder the following possibilities:
- (=) If one regards the 'distance' between the state of the art and the goal as equal, then plastination's faster progress is a win
- (<) If one regards the distance as smaller for plastination than cryonics, then plastination wins both on faster progress and how much is left to do
- (>) Only if one regards the kidney as being *much* closer to a reviving a functioning brain can it be possible for cryonics revival to beat plastination revival.
Pondering the Roadmap and the Blue Brain project, I strongly doubt the kidney-brain is much closer together than connectome-upload, and suspect that the latter is closer.[^dna]
2. If plastination turns out to be the 'right' starting point for an upload and cryonics brains must be plastinated first, we might expect the cryonics->plastination process to be *more* lossy than recently-deceased-brain->plastination process. It could be that warming the brain up enough to plastinate does damage, or that the cracks caused by vitrification are not reparable and degrade the plastinated result.
[^businesses]: ["The Armories of the Latter Day Laputas, Part 5"]( has the statistics. Besides 98% of startups dying, established companies die frequently: "...if we “re-set” the graph at 5 years, and then follow the remaining cohort of enterprises out to the 10 year mark, the mortality rate is still quite high with only 29% of businesses surviving." The total mortality is considerable: "Thus, the chances of a business entity (excluding religious and academic institutions) surviving for >100 years is 1.096%" One sometimes see people provide their own values for a cryonics Drake equation - often the result is a comforting 1-5%. This shows they expect to be revived *very* soon, think cryonics organizations are exempt from these statistics, or are unaware. Being non-profit helps only a little: "However, by the 30 year mark, ~95% of NPOs have failed."
[^dna]: I have a general skepticism about applied medicine and biology (and revivification is *very* applied), from a lifetime of broken promises and failed predictions about the coming fruits of medicine and biology. I recently ran across an example in a [Tanner lecture](!Wikipedia) [by Donald Brown](, then an accomplished professor of biology at Johns Hopkins:
> "We don't know yet how these genes work, but techniques of modern genetics which led to the discovery of these genes in the first place will provide these insights. In the next ten years we are going to understand better and perhaps even cure some of the most serious diseases that afflict mankind, such as diabetes, arteriosclerosis, parasitic diseases, the common cold, cystic fibrosis, certain kinds of arthritis, immune diseases, and infectious diseases, just to name a few. A molecular basis for at least some kinds of schizophrenia will be found. We will learn about the biochemistry of the aging process, which also has a strong genetic component. This doesn't guarantee prolongation of life, but rather an improvement of the quality of life in old age. We need sensitive assays for the effects of chemicals, pollutants, and drugs as causative agents of birth defects like those developed to determine carcinogenic potential. There have yet to be developed simple, safe, and reversible contraceptives for males."
This reads like it was written yesterday, and not in 1984 - more than 27 years ago. The predictions about the Human Genome Project have fared little better. My rule of thumb is that in the future, our understanding and information will outstrip our laboratory prototypes by even more than today, and the prototypes as much outstrip the generally available products; hence, I am unsurprised by the astounding progress in DNA sequencing, and equally unsurprised by the astounding dearth of new drugs and treatments. Fortunately for plastinated brains, enough information and understanding can make up for stasis in other areas; as long as computers and scanning technology continue to advance, things may yet work out for them.
## Disadvantages
1. Threatens information preservation parameter #2 in several ways:
1. can plastination preserve the level of detail required for reconstruction? Unknown.[^perry] The [Brain Preservation Technology Prize ]( is attempting to spark research.
Cryonics assumes, based on analogous near-death experiences, that many things like dynamic electrical activity, can be disregarded for the purpose of [personal identity]( Plastination is known to preserve overall neural structure in high resolution, as evidenced by current plastination techniques sufficing to create connectomes, but what does it miss? It misses the dynamic activity, like cryonics, but cryonics preserves things plastination may not. Does plastination preserve neurotransmitter levels? (It seems inconsistent with the general idea of plastination.) Neurotransmitter levels change endlessly, but levels of neurotransmitters can be the difference between sanity and insanity in the living; on the other hand, personal identities persist even through careers of massive head trauma like boxing or football, which affect neurotransmitters (see [Fencing response](!Wikipedia)). What might we be missing?
2. are the methods well-studied and implemented even if they are capable in principle of preserving the necessary information? They have been widely used in neuroscience, but there are no checks or 'round trips' showing that information and functionality is preserved with normally executed techniques - at least cryonics has frozen rabbit kidneys to test itself on, what does plastination have?
Counter-point: brain scanning and the associated plastination techniques are an extremely hot field of research, which is improving at an amazing clip akin to DNA sequencing. This ought to give us considerable confidence in its current and future techniques. (This also raises an interesting point that anyone not dying in the next decade or two is wasting their time by investigating plastination. It's entirely possible that for a young or middle-aged person, the field will either have succeeded in plastinating an animal or human brain and then uploading it, or will have dead-ended and the fundamental limits discovered, by the time they truly need to choose between cryonics and plastination.)
3. Are the plastination processes *fast enough*? Normal brains are preserved over weeks to years, which is strictly worse than a hypothetical equally good process which requires hours. Cryogenic cooling appears to be intrinsically faster than chemical diffusion and action. How much damage does the extra time required do? (There's some [weak evidence]( that the rate of degradation is somewhat constant and hence the damage linear over time.)
2. Threatens revival parameter #5: a vitrified brain can, presumably, be plasticized if necessary. However, a plasticized brain is permanently plasticized. The plasticized brain has only *1* option. A vitrified brain has *2* options: normal freezing and repair (whatever that will be), and the plasticized route (scanning and upload, likely). A disjunction of two probabilities is at least as likely as either disjunct. Ease of revival also affects how long storage must succeed - if revival is feasible for both, but cryonics is easier, the cryonics brain will have to last a shorter period than the plastinated brains. (This cuts both ways: if plastinated brains are easier to revive or upload, then it will be the cryonics brains which lose some probability due to the increased wait-time.)
This may not be a large advantage for cryonics. Most cryonics advocates seem to expect uploading will be the ultimate solution, inasmuch as brain scanning is advancing a lot faster than medical nanotechnology (see the [Whole Brain Emulation Roadmap](, but there's still a small probability that a non-upload organic solution will be used, and this small probability is forfeited in the plastination route.
[^perry]: From Perry's article about chemical fixation:
> "As with cryonics itself, the basic answers are unknown. Some encouragement is provided by the high level of detail seen in preserved brain samples using, for example, formaldehyde fixation. Ultrastructural details under the high magnification of electron microscopy (10,000x plus) are quite clear, though this alone is not a demonstration that all the details one would like are present. However, the same problem exists with tissue preserved cryogenically—the answer to whether the preservation captures fine enough details is unknown though there are at least some encouraging signs along with reasons for concern."
He is not so sanguine about plastination;
> "A possible drawback of this approach, from the standpoint of preserving the fine structures that are especially important from a cryonics standpoint, is the relatively harsh regimen needed to produce the finished product. Typically, the process starts with an aldehyde-fixed specimen in aqueous solution. The specimen is placed in acetone, and successive changes of the bath remove water and fats. Finally the resin monomer is introduced, the remaining acetone is removed by vacuum, and induced catalysis yields the desired polymerization. Concerns have been raised about whether defatting would obliterate important brain information, though there does not appear to be strong evidence of this. (Here it is appropriate to mention that lipids nevertheless could contain important information; preservation of lipids is a difficult process that has not been covered in this preliminary survey but deserves consideration.)"
Olson mentions lipids in passing:
> "A second example of redundancy involves the locations of the neuronal membranes (i.e. the neuronal configuration). The information of the membranes' positions is contained not only in the physical positions of the membrane lipids, but also in the cellular cytoskeleton (which is made of proteins) whose purpose is, among other things, to hold the membrane in its configuration (15). Thus, even if a substantial proportion of lipids were extracted in the course of chemical preservation of a brain (as is the case with some preservation techniques), it is plausible that the information of the neuronal configuration would still exist in the crosslinked cytoskeletons of the neurons."
Plastination is one-way, while with proper techniques, the brain can be cryonically stored such that it can later be plastinated (in case of an extended emergency eg.); [Mike Darwin]( did some preliminary experiments in this area and forecasts what such techniques might one day look like:
> One of most difficult problems to be overcome when applying this technique to a whole organ the size of a human brain is, how do you keep the circulatory system accessible to allow for the replacement of the water in the tissue with the monomer that will subsequently be polymerized into a solid plastic, and to remove the truly enormous amount of heat liberated by the exothermic polymerization reaction?
> Figure 14: A corrosion cast of the circulatory system of the human brain. The extensive vascularization of the brain allows for use of the circulatory system as both a mass and heat exchanger. Gas perfusion of the circulatory system prior to cooling to vitrification temperatures leave it accessible during cryogenic storage should fixation and plastination become necessary as a fallback position to cryopreservation.
> This slide (Figure 14) shows the circulatory system of a human brain. This is the real deal, not a model. What you are looking at is something called a “corrosion cast.” In this case, the arterial circulation of a human brain was injected with a red-tinted plastic material and the brain was then immersed in a strong base, such as a concentrated solution of sodium hydroxide. The base dissolves or corrodes the tissue away, leaving behind the red plastic framework of the arterial circulation. It’s easy to see that the human brain is a “strongly circulated” organ – in fact, the brain normally received 1/3rd of the resting cardiac output – about 1.5 liters of blood per minute. The FFP researchers decided that the best way to achieve both heat and mass exchange was to keep the brain’s circulatory open and accessible throughout the procedure. In order to achieve this during solidification of the brain, they turned to gas perfusion – replacing the liquid in the circulatory system with gas.
> One of the investigators (Mike Darwin) realized that if the circulatory system of human cryonics patients was similarly perfused with gas during cooling to vitrification, not only would cooling be hastened, thus reducing the risk of freezing, but the circulatory system of the patient would remain accessible, even during storage at -150○C. What this meant was that it would thus be theoretically possible fix and plastinate cryonics patients in the event that cryopreservation was no longer possible.
> In this scenario, a patient would be removed from storage to a special apparatus, the Final Fallback Position System (FFPS), where his arterial circulation would be connected to a recirculating system of solvent chilled to -100○C. This solvent would be pumped through the patient and would begin dissolving the viscous cryoprotectant-water solution in the patient’s tissues. The solvent would also contain fixative – initially formaldehyde to fix the proteins and, finally, a highly reactive metal, osmium tetroxide, that is necessary to fix the lipids; which comprise both the cellular and the intracellular membranes. Once the patient had been “solvent substituted” and fixed in this fashion, it would then be possible to safely warm him up to room temperature and introduce the monomer required for plastination. In fact, if necessary, this could be done by immersion, rather by perfusion (though this would necessitate removal of the brain from the head).
## Analysis
Counting the discrete items, we found 4 for plastination and 2 against (yes, one point is counted twice). This is a useless count, of course. Of those favorable 5, 2 seem to me to be probability differentials of magnitude. Of the unfavorable 3, 1 seems to be of magnitude. This count favors plastination as well.
I believe the above fairly sets out the signs of all the relationships, but it is difficult to fill in specific numbers for oneself, and even more difficult to defend those numbers.
The fundamental question is, does the rapid advance of scanning and the robustness against organizational failure of plastination outweigh the risk that cryonics uniquely preserves key information?