If an American signs up for cryonics and pays their ~$300/year, what are their odds of being revived? Talking to people at LessWrong meetups I've heard estimates of 1 in 2.  My friend George Dahl, whose opinion I respect a lot, guesses "less than 1 in 10^6". Niether has given me reasons, those numbers are opaque. My estimate of these odds pretty much determines whether I should sign up.  I could afford $300/year, and I would if I thought the odds were 1:2, but not if they were 1:10^6. [1]

In order to see how likely this is to work, we should look at the process. I would sign up with a cryonics company and for life insurance. I'd go on living, enjoying my life and the people around me, paying my annual fees, until some point when I died. After death they would drain my blood, replace it with something that doesn't rupture cell walls when it freezes, freeze me in liquid nitrogen, and leave me there for a long time. At some point, probably after the development of nanotechnology, people would revive me, probably as a computer program.

There's a lot of steps there, and it's easy to see ways they could go wrong. [3] Let's consider some cases and try to get probabilities [4]:

Update: the probabilities below are out of date, and only useful for understanding the comments.  I've made a spreadsheet listing both my updated probabilities and those for as many other people as I can find:  https://docs.google.com/spreadsheet/...

0.03 You mess up the paperwork, either for cryonics or life insurance
0.10 Something happens to you financially where you can no longer afford this
0.06 You die suddenly or in a circumstance where you would not be able to be frozen in time (see leading causes of death)
0.04 You die of something like Altzheimers where the brain is degraded at death (Altzheimers is much more common than brain cancer)
0.01 The cryonics company is temporarily out of capacity and cannot actually take you, perhaps because lots of people died at once
0.02 The life insurance company does not pay out, perhaps it's insolvent, perhaps it argues you're not dead yet
0.02 You die in a hospital that refuses access to you by the cryonics people
0.02 After death your relatives reject your wishes and don't let the cryonics people freeze you
0.10 Some law is passed that prohibits cryonics (before you're even dead)
0.20 The cryonics people make a mistake in freezing you (how do we know they don't make lots of mistakes?)
0.20 Not all of what makes you you is encoded in the physical state of the brain
0.50 The current cryonics process is insufficient to preserve everything
0.35 Other (there are always other things that can go wrong)
0.86Something goes wrong in getting you frozen

0.30 All people die (nuclear war? comet strike? nanotech?)
0.20 Society falls apart (remember this is the chance that society will fall apart given that we did not see "all people die")
0.10 Some time after you die cryonics is outlawed
0.15 All cryonics companies go out of business
0.30 The cryonics company you chose goes out of business
0.05 Your cryonics company screws something up and you are defrosted (power loss, perhaps. Are we really expecting perfect operation for decades?)
0.30 Other
0.80Something goes wrong in keeping you frozen

0.10 It is impossible to extract all the information preseved in the frozen brain
0.50 The technology is never developed to extract the information
0.30 No one is interested in my brain's information
0.40 It is too expensive to extract my brain's information
0.03 Reviving people in simulation is impossible
0.20 The technology is never developed to run people in simulation
0.10 Running people in simulation is outlawed
0.10 No one is interested running me in simulation (even though they were interested enough to extract the neccesary information from my frozen brain)
0.05 It is too expensive to run me in simulation (if we get this far I expect cheap powerful computers)
0.40 Other
0.93Something goes wrong in reviving

0.05 Other
0.05Something else goes wrong

Combined Probability Of Failure: 99.82%

Odds of success: 1 in 567.

If you can think of other ways cryonics might fail, moving probability mass from "other" to something more quantifiable, that would be helpful. If you think my numbers are off for something, please let me know what a better number would be and why. This is not final.

Am I going about this right?  Do people here who think it's rational to sign up for cryonics take a "the payoff is really high, so the small probability doesn't matter" view?  Am I overly pessimistic about its chances of success?

Note: I originally posted this on my blog, and the version there has a silly javascript calculator for playing with the probabilities.


[1] To figure out what odds I would accept, I think the right approach is to treat this as if I were considering signing up for something certain and see how much I would pay, then see what odds bring this below $300/year. Even at 1:2 odds this is less effective than Village Reach at averting death [2], so this needs to come out of my 'money spent on me' budget. I think $10,000/year is about the most I'd be willing to spend. It's a lot, but not dying would be pretty nice. This means I'd need odds of 1:33 to sign up.

[2] Counter argument: you should care about quality adjusted life years and not deaths averted. Someone revived maybe should expect to have millenia of life at very high quality. This seems less likely to me than just the claim "will be revived". A lot less likely.

[3] In order to deal with independence issues, all my probability guesses are conditional on everything above them not happening. Each of these things must go right, so this works. For example, society collapsing and my cryonics organization going out of business are very much not independent. So the probability assigned to the latter is the chance that society won't collapse, but my organization goes out of business anyway. This means I can just multiply up the subelements to get probabilities for sections, and then multiply up sections to get an overall probability.

[4] This has a lot in common with the Warren formula, which was inspired by the Drake equation. Robin Hanson also has a breakdown. I also found a breakdown on LessWrong that seems really optimistic.

EDIT 2011-09-26: jsalvatier suggested an online spreadsheet, which is very sensible.  Created

EDIT 2011-09-27: I've updated my probabilities some, and made the updates on the spreadsheet.

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0.10 Something happens to you financially where you can no longer afford this

This one seems conceptually strange in a cost-benefit analysis: if you get into straits in which you don't want to pay your insurance premia and membership fees, then you stop paying and lose the protection (unless you have been suspended or died in the interim). In this situation both the costs and benefits are reduced, so it shouldn't play the role it does in the above calculation.

0.03 You mess up the paperwork, either for cryonics or life insurance

This rate is empirically too high.

0.20 Not all of what makes you you is encoded in the physical state of the brain

Why so high?

0.35 Other (there are always other things that can go wrong)

One does have to inform this probability by historical rates.

Something goes wrong in reviving

A lot of these claims are going to be correlated with each other and brain preservation adequacy (from the first section), likewise for technological/economic capacities and interests. If you apply a mistaken independence assumption and break apart many correlated things you'll get big underestimates of probability.

How sure are we that electrical information is not important? That the neurons in other parts of your body are not very important?
Brain electrical activity can collapse to undetectable levels and be recovered from. One can think about amputees and the like, and your own degree of attachment to certain kinds of muscle memory, etc.
Ok. I've revised my probability down to 2%. Updated in the google doc. Thanks!
be from?
Mangled link.

This is not the first time I've seen an attempt at calculating it; I will note that it's interesting that the more steps you add, the lower your probability gets. It's a strange kind of analysis that can only go downwards...

Could this just be that people overestimate how likely things are until they really start getting into all the things that could go wrong?

That is true, but this style of analysis is predicated on a sequence of steps, each one of which must succeed, and hence the more steps you have, the lower the end result probability must be; if you were just correcting for overestimation by analysis, then there ought to be analyses or points where one realizes one has been too pessimistic and increases the probability.

But that can never happen with this kind of analysis: the small result is built into the conjunctions. If one realizes one was wrong in giving the probability of a particular factor, well, one can just 'fix' that by breaking it into some more substeps with <1 probability!

And if you look, there are illegitimate conjunctions in the OP. For example, 'cryonics company is out of capacity', besides being way too high (notice that '86% chance 'something goes wrong in getting you frozen' fails a basic outside view test - suspensions do go wrong fairly frequently, but not anywhere close to 86% of the time!), is a false conjunction; if you're paid up for Alcor, why can't CI handle your case or vice versa? Cryonics companies have taken patients off each others' hands before.

If we have actual data on this, this should replace most of my first section. Can we get it? Though the people in a position to collect the data have a lot to lose by admitting poor numbers. Also, some of my 86% for the first section includes things that we can't tell yet if they worked out all right: * Not all of what makes you you is encoded in the physical state of the brain * The current cryonics process is insufficient to preserve everything And then there are things that are not currently a problem but could become one: * Some law is passed that prohibits cryonics * You die in a hospital that refuses access to you by the cryonics people Actual data on the fraction of the time someone signed up for cryonics is actually suspended in what we think was the correct way would be really helpful, though.
http://www.alcor.org/cases.html seems like a good starting point.
Ugh. Some of that makes for very horrifying reading. One of the ones labeled worst case scenario makes me want to track down the people who did the autopsy and punch them.
I did say 'fairly frequently'.... Nor does long involvement necessarily save one; Mike Darwin was rather angry at Ben Best over how he botched Curtis Henderson.
Some of my points seem unlikely enough now that I'll probably remove them. For example: * The life insurance company does not pay out * The cryonics company is temporarily out of capacity One could also break a step S with X% probability into several steps that combine to less than X% probability if after looking at all the ways S could happen you decided that they combined to be less likely than you originally thought S was.
No, in this disjunction of conjunctions, the more details of any kind you add, the less likely a favorable outcome looks. If we expect reality to be unbiased, we should also expect some ratio of favorable to unfavorable details, which, ceteris paribus, should be maintained as we go to higher granularities of detail. In other words, "motivated stopping" and "motivated continuation" should not, together, be a sufficient explanation for the results of an analysis.
Say I went into this thinking my chance of being frozen correctly was 95%. Now, with more details on what has to go right for this to happen, I think 86% is a better estimate. Details don't have to make things less favorable. They just usually do because we are optimistic. EDIT: that "correctly" above should have been an "incorrectly".
...but then you think and research for longer, and find out in even more detail what could go wrong, and your estimate drops to 80%. If you can predict which direction your belief will move in the future, something went wrong somewhere.
I'm sorry, I meant to write "incorrectly".

.03 seems really high for messing up the paperwork. Sure you might mess up the initial paperwork but then it will be noticed and fixed.

.06 seems too low for chance of dying in a circumstance where they can't preserve you. Especially if one isn't very old, the chance of death from sudden trauma is much higher than other forms of death.

The Alzheimer's thing is overestimated. One can in many places (and the number of places is growing) engage in euthanasia. Even in the US people can directly take steps to drastically decrease their lifespans such as by self-starvation. Also, unless you die in very late stage Alzheimer's most of the information is likely to be intact. Alzheimer's also has a very large genetic component, so if no one in one's family got it one is probably safe.

I don't know why you think the cryonic's company running out of capacity should be that likely- with so few people signed up that simply isn't a serious risk.

The insurance company issues aren't a problem. There are companies now which have policies geared to cryonics. And if a company goes insolvent, unless this happens just when you are dying, switching to another insurance company should not be hard.

You seem t... (read more)

The law in BC only prohibits selling cryonic services, not getting frozen and transported elsewhere: clarification
Huh. I wonder. By the wording of that law, a religion that felt that certain forms of burial were needed for an eventual resurrection would not be able to sell funeral plots. I wonder if there are any religions which would get hit by this?
It is also illegal in France. See http://www.depressedmetabolism.com/2010/10/11/october-2010-cryonics-symposium-in-germany/ : "In the late 1960s the Cryonics Society of France was the largest cryonics organization outside of the United States. Roland was the President and Anatole Dolinoff was Vice-President. Roland showed me a list of officers and directors of the organization, pointing-out who had been fighting with whom, and the fact that virtually all were dead without having been cryopreserved. Dolinoff believed that cryonics was illegal in France because of a decree issued by the French Minister of Health in 1968." Also see http://www.cryonet.org/cgi-bin/dsp.cgi?msg=7353 Possibly this could be due to fear of the spread of US culture into france. See, for instance, how the French also recently banned the use of the words "facebook" and "twitter" on tv: http://www.huffingtonpost.com/2011/06/03/french-ban-twitter-facebook_n_871153.html
Do we know how common it is for someone who thought they were signed up for cryonics to not actually be frozen because something was screwed up with the paperwork? There's the cryonics organization, life insurance, and your will. Maybe other things? If I die now (age 25) then yes, it's most likely to be because of an accident. But I'm also unlikely to die now. Looking at overall causes of death, 5% of american deaths in 2007 were due to "accidents (unintentional injuries)". Another 0.8% were due to homicide. I assumed that within the 18.6% of 'other' there might be ~0.2% of other similar things. I could die of something like a heart attack while far from a hospital or something, though. So I should probably raise this probability to account for that. Do we know how common it is for people to die suddenly, of all causes (excluding accidents and homicide, which I'm already assuming are 100% no-freeze)? Would 0.20 be better? I don't know if I would want to be euthanized/frozen if I thought my chances of revival were this low. In my case, I don't think I have had any relatives with it. For the general case, I should probably put in a note. Something might kill a lot of people at once. This is unlikely, but is it more than 1% unlikely? I had thought life insurance worked such that if when I'm 60 my company goes bust getting a new policy would be prohibitively expensive? I didn't know about this. That is worrysome. Would you put it closer to 0.25? I am. Direct revival seems really impractical to me. Should it? I convert all the probabilities of failure to probabilities of success by subtracting them from 1. Then I multiply them all and subtract the result from one: P(failure) = 1-P(success) P(total_success) = P(success_a)*P(success_b)*P(success_c)*... This seemed to me to be the only way to do it, so I didn't remark on it. Is this actually the right way to do it? Are there other ways that I should have considered? (I tried to deal with independence in footn
I'm not aware of any such cases. Perhaps someone more involved with cryonics can comment on this? As to accidental death and related issues- I'm not sure. Given your analysis you've added in this comment I'm more inclined to accept your original number. Well, if something killed a lot of people it would likely be a heavily traumatic event, so that would be already accounted for. Even a sudden plague would create disruption. So I don't think that there's any at all likely scenario where there's a disaster that causes a sudden influx of cryopatients and doesn't trigger one of the other failure modes. I have trouble even imagining what that sort of situation would look like- maybe an meteorite striking a cryonics convention? Unsure. The cryonics law seems to be a fluke, and see the other reply to my remark which notes how the law in practice isn't nearly as restrictive as one might think. I don't think that direct revival seems substantially more impractical than uploading. I suspect that uploading will likely come first, but I don't see why sufficiently advanced nanotech couldn't handle direct revival. There's also a non-trivial number of cryonauts and people considering cryonics who are more comfortable with revival than uploading. Well, yeah this works if they are all independent probabilities. But some of them are clearly not. For example, a lot of the worst case post-preservation problems are likely to be correlated with each other (a lot of them have large scale catastrophes as likely causes). Those should then reduce the chance of failure. But at the same time, other possibilities are essentially exclusive- say dying from Alzheimer's or dying from traumatic brain injury at a young age. That sort of thing should result in an increased total probability. Working out how to these all interact might require a much more complicated model (you mentioned the Drake equation as an inspiration and it is interesting to note that it runs into very similar issues). But
How about a deliberate attack at a cryonics convention? There was stuff about nanotech researchers getting bombs in the mail, I don’t see why it wouldn’t happen to cryonicists, especially a couple of decades from now when it cryonics might be more popular (i.e., higher on the public radar) than now. On that note, at first thought it doesn’t seem like it would take enormous effort for someone to sabotage a cryonics facility. (Remember, you don’t have to destroy it completely, you just need to partially thaw for a short while or otherwise damage the what I imagine are closely-packed brains; given they’re stored in liquid nitrogen, even just fracturing the dewars might be enough: you can’t quite send someone to fix them until the temperatures rises a lot.) This might not be a big risk today, but if cryonics does get even a little bit mainstream in the future it’s easy to imagine all sorts of people who might want to do that. (A well-meaning if not quite reasonable person who just wants to save the thousands of frozen people from missing on Heaven is what my brain popped out right now. I’m sure reality will find something even sillier.)
That's a really good set of points. This almost suggests that a sufficiently selfish cryonist might want to optimize how popular cryonics becomes. Popular enough to provide longterm security and pull but not so popular to be a target.
The other benefit would be on the revival side. My brain's information is more interesting the fewer peers I have from my own era. These revival problems are actually one of my larger concerns. I can't imagine why anyone would want to run an upload for more time than it would take to have a few conversations.
I tried to define them to be independent: So my probabilities were supposed to be like: P(failure1) P(failure2|-failure1) P(failure3|-failure2&-failure1) P(failure4|-failure3&-failure2&-failure1) In some cases they are probably unrelated. Then we can simplify: P(society falls apart | nothing goes wrong in freezing you) can be almost perfectly approximated as P(society falls apart)
Right, but some of them are clearly not independent. See my example of forms of deaths where they are essentially exclusive.

You seem to be assigning a high probability to exotic problems (information isn't preserved by freezing, global apocalypse) and a low probability to mundane problems (you die of Alzheimer's, cryonics companies go out of business). The reverse seems more likely to me.

The nice thing about these mundane probabilities is that we have precedent and can calculate them. Not that many people die of Alzheimers; it's pretty rare. We don't have a reason to think it's going to get more common, do we? But new technology I know little about could kill everyone. Or there could be something (electrical?) needed for the brain to work, and freezing doesn't capture it. Without data that we don't have yet (actually reviving a vitrified brain, seeing what gets invented and how it is applied) I don't think it makes sense to assume bad outcomes are unlikely. I think you (and several other people) are right that the company going out of business is more likely than I have it; one already did.
It's worth noting they went out of business due to very bad financial practices, and all the major firms take a pretty paranoid view of economics to ensure this doesn't happen again. My gut instinct is that it's now a lot LESS likely than it used to be, because of the precautions it inspired.

You die of something like Altzheimers where the brain is degraded at death

Not all of what makes you you is encoded in the physical state of the brain

The current cryonics process is insufficient to preserve everything

You've then got to weight these things against how much you would count a less-than-perfect revival as a partial success. The me that's alive today, after all, is not the same person, in opinions, memories, even abilities, as the me of twenty years ago, but I still count both as "me".

I took your estimates, and sorted them into categories. These are the categories I came up with and their total probability of failure, by your estimate:

0.90 Insurmountable technical obstacle (cryonics process at the time you die (not necessarily today) doesn't preserve everything, or technological development stops prior to development of molecular nanotech, or molecular nanotech doesn't do what we think it does and no substitutes exist)
0.74 Other (wtf?)
0.625 Society chooses to let you die or not resurrect you (companies go bankrupt and no one takes over the maintenance; or no one does the resurrection, conditional on no legal problems)
0.56 Societal collapse or human extinction
0.27 Cryonics or resurrection is banned (but I think this is strongly correlated with societal collapse - they're both caused by insanity)
0.27 You aren't actually frozen or your brain is badly damaged first
0.24 Cryonics companies screw up (improper freezing or later thawing)
0.2 You are not your brain
Overall probability of failure: 0.998

This is wildly, wildly pessimistic. Here are my estimates for the same categories:

0.3 Insurmountable technical obstacle
0.0 Other (this list is exhaustive)
0.05 Cryonics o

... (read more)
I believe that the point of "other" is some sort of Black Swan event that isn't anticipated by his list. By nature such things are difficult to estimate. I agree that the parent's estimate for this looks way too high. (Part of why humans have trouble dealing with Black Swan events is that they are so rare.) But I'm not sure rounding this down to 0.0 seems good.
That strikes me as an astonishingly high estimate for "You are not your brain." Care to elaborate? Agreed that the list overall is pessimistic, but I would have revised that one way lower.

That strikes me as an astonishingly high estimate for "You are not your brain." Care to elaborate?

I was going to say something about matrix universes and the possibility that I'm systematically deceived, but then I realized that the real answer for why I gave such a high estimate (0.05) is that I started with Jeff's estimate of 0.2 as an anchor.

(I think jfaufman was originally thinking of the possibility that the spine and peripheral nervous system are important, but you can get those frozen too.)

Why do you think its only a 10% chance your cryonics company will screw up? That has happened before. Same with Cryonics being banned - it has happened! Over the course of a lifetime and all the time you are in hibernation you think there is only a 5% chance of that happening where you live? Yes its insane to ban Cryonics, and people are not getting any saner as technology improves. 80% chance that you are so awesomecool that future society wants to run your upload for a long time? I think its at least as likely that instead of running a simulation of every corpsicle from our Era, just the most interesting ones are run a lot of times by a lot of different people who want to interact with those simulations. Yes we're talking about a future with fantastic amounts of computing resources so it wouldn't cost much, but one problem is that a lot of resources are going to be spent working out new projects to run; I'm sure there will always be more computing people would like to do than they actually can do.
I assume you're referring to the Chatsworth disaster in 1979 where after CSC's first body in 1967, it ultimately failed and let the bodies thaw. Let's do some quick figuring. So Chatsworth ran 12 years (1979 - 1967) and had 1 major failure. ALCOR's first body was in 1976, and it has never failed, so that's 37 years of operation so far with 0 major failures. CI got its first body in 1977, so that's 36 years of operation with similarly 0 major failures. This sums to 12+36+37=85 years of operation with 1+0+0 major failures or 1 failure over 85 operation-years. Xachariah uses the nice round figure of 100 years before revival in his comment, so I'll just use that. If the risk of failure is 1/85, then the odds of going 100 years without any failures is (1-(1/85))^100 or 30% rate of success or a 70% risk of a screwup. And obviously it goes down each year that passes without CI or ALCOR screwing up so badly as to let bodies thaw, so next year it'll look more like a 68% chance (1 - (1-(1/87))^100) and then 67% and then 66% etc. I personally don't expect to need cryonics before 2060, so if we hypothesized that CI & ALCOR make it until then with no Chatsworths, then that alone will drive it down to 42% (1 - (1-(1/(85+((2060-2013)*2))))^100). And of course 70% is a crude upper bound, because Chatsworth failed early on compared to CI or ALCOR (indicating that the survival curve does not look like a constant exponential risk), those were designed in response to Chatsworth and were intended to avoid the same problem so they aren't in the same reference class, this weights the groups equally so it ignores how CI & ALCOR have hundreds of bodies rather than the 9 that CSC had, this doesn't take into account the arrangements between organizations to take bodies if one of them fails, and I haven't included any other cryonics groups (I haven't heard of any disasters elsewhere so I assume if there are active organizations besides CI & ALCOR, they must not have failed yet). Taking the
The alternatives to not waking people up, if the technology exists to do so, are to either keep them frozen or let them die. At some point in time the former is probably going to cost more than revival. We can't discount the possibility that they will just let everyone who's not interesting die, but that would be a strange future indeed, and not one that I personally would like to be revived in.
I doubt "interesting" will be the metric, but is that substantially worse than our current scenario, where we let people die as a result of them having insufficient funds to direct resources towards themselves even when said resources are in fact available?
Well, I'd chalk up today's lack of enthusiam towards cryonics as more ignorance than anything else. You do have a point though; we do not seem to be very enthusiastic about keeping people from dying. If anything, we seem to embrace it.
Cryonics is also an instance of this, but I actually had more vanilla sorts of altruism in mind when I wrote the comment, such as medical care, clean water, mosquito nets...the resources to prevent premature death exist, I don't think ignorance is really an issue, and the average citizen even agrees that we aught to do more, and no one really embraces pre-mature death...and yet it doesn't always happen, largely because of the idiosyncrasies of our resource allocation system. So my meaning is, in the future, if some frozen corpses fall through the cracks of the future resource allocation system, I wouldn't consider that as evidence that this future is inferior to the present, nor would I consider it a strange future with alien values. Our present age allows people to fall through the cracks in much more egregious ways.
Perhaps people signed up for cryonics should try to make themselves as interesting as possible as publicly as possible?

I'd like to see more emphasis on the question: What do we have to do to make cryonics work?

The critics who dismiss cryonics for reasons like the failure points mentioned above have a defensible point of view, given how they've framed the problem.

Someone who thinks like an inventor knowledgeable about biology, by contrast, could say, "No, no, no! Cryonics won't work if you do it THAT way!" He might then try to imagine end results of successful revival from cryostasis, then work backwards based on current scientific knowledge and a parsimonious use... (read more)

How exactly have you arrived at these probabilities ? For example, why is the probability of "all people die" 0.3, as opposed to 0.01 or 0.9 ? These numbers seem to be completely arbitrary to me, but maybe I'm missing something.

Any summary report of probabilities is going to sound arbitrary in some sense. I'd prefer a norm that doesn't demand an impossible standard of detail to state current views for every point, which discourages people from making themselves clear in this way. Instead, people who disagree for communicable reasons can challenge particular premises and the poster can engage on them. This role, of making beliefs explicit so as to focus discussion on productive areas, seems worth protecting.

Fair enough, but surely there's some room between "an impossible standard of detail" and "totally arbitrary". I could very easily produce a table of probabilities similar to jkaufman's (or, presumably, yours, if you have one) simply by rolling a d100 a bunch of times. Then, I'd multiply all the numbers together and proclaim, "ah hah, there's a 1 in 234 chance that cryonics won't work for me". I think we can both agree, though, that such a process of assigning probabilities to events doesn't have much predictive power. So, can you suggest a better process ? How would you go about determining the probability of, say, "all people die" or "the cryonics company takes your money and runs", or whatever ? Note, I'm not asking for a specific number (yet), but only for the process that you'd use to arrive at an estimate. Of course, I'd be interested in hearing about jkaufman's method, as well.
For some of the cases where I can look up data (chance of altzheimers, etc) I did so. For most of the other things I gave rough guesses.
Ok, that makes sense. I think it would be useful if you could annotate your list with references where possible, for things like the chance of Alzheimer's, cancer, etc. This way people who disagree with your probabilities have something to go on. As for the rough guesses, I'm still unclear what they're based on -- can you elaborate ? In addition, many of the items on your list depend on the time span. To use a trivial example, the probability of "all people die" approaches 1.0 as time goes on, culminating in the heat death of the Universe. Thus, it would be helpful if you provided the rough amount of time you expect to spend frozen, along with an explanation of why you picked this time span in particular.
Amen. (I wish I could hyper-mega-upvote this.)

The probability that cryonics will work likely exceeds 85%, discounting dystopian futures, assuming a good quality of cryopreservation, and assuming that MNT is developed more or less as expected.

The usual error made in these analyses is to imagine many different kinds of "disasters", all correlated, that could cause cryonics to fail, and then multiply their probabilities together. But because all the probabilities are correlated, the resulting overall probability is unrealistically low, often by orders of magnitude.

The only real problems are (a)... (read more)

You write off as 0% likely a whole lot of things I would put at at least 20%, such as alcor falling apart and nanotechnology not being developed. Those things a̶d̶d̶ multiply up. I have a vague impression that "the laws of physics are reversible" is not actually true.

I have a vague impression that "the laws of physics are reversible" is not actually true.

Well, it's not like the Second Law of Thermodynamics is a law of physics. It'd be in the title or something.

Two meanings of "reversible" here: 'can be run in reverse' vs 'from looking at the current state we can determine all prior states'. I believe merkle was using the second meaning and you're arguing against the first. Though I don't know very much about this.
The 2nd law doesn't argue against the first meaning, that microscopic events look the same in both time directions. That's true. The reason that doesn't generalize to macroscopic events (i.e. the 2nd law arguing against the second meaning) is illustrated by diffusion. Suppose you have a sufficiently hot interface between two pure metal slabs- there's lots of vacancies and the atoms are dancing around in the crystal structure. At the interface, you might have a vacancy surrounded by three atoms of metal A and two atoms of metal B. Each atom is roughly equally likely to hop to that vacancy, but it's 60-40 that an atom of metal A will move there instead of an atom of metal B. The result is that a sharp interface becomes a diffuse interface until eventually you have one slab of both A and B, with local distributions of A and B in thermal equilibrium with each other. Once this has happened, you won't be able to tell which side of the slab was originally A and which side was B. What makes cryonics work is that it's very cold, which means that diffusion happens on massive timescales. The main question I have about information-theoretic death is how long someone's brain has to be dead at room temperature for information to be permanently lost. The long-term damage of even a few minutes of anoxic deprivation before standard revival is massive. What information you need from a frozen dead cell to make a functional live cell isn't well known- if it's just the knowledge that neuron A is connected to neuron B, we're in good shape. If it's what the local ion distributions were in the cellular soup and you let them diffuse for thirty minutes, it might be impossible.
Well, there's also acoustic fracture events, which Alcor cops to in their FAQ but sort of downplays the significance of. Even though vitrification prevents ice crystal formation, fractures occur at just a few degrees below the glass transition. Feeling lucky about the odds of checking and correcting the damage to 10^15 unmapped connections?
If cryonics is not performed extremely quickly, ischemic clotting can seriously inhibit cortical circulation, preventing good perfusion with cryoprotectants, and causing partial information-theoretic death. Being cryopreserved within a matter of minutes is probably necessary, barring a way to quickly improve circulation.

Can I suggest putting this calculation in a google doc so it's easy for people to copy and work out their own estimates?

That's a good idea. I'll do that and add it to the post.

I upvoted because this is a good effort to make your probabilities explicit.

One meta point: A lot of this seems a bit too nihilistic. Cryonics is small, very small. If you, Jeff Kaufman, decide (and actually go through with the process) of signing up, that act non-trivially decreases the probability that cryonics will be outlawed. If you decide to contribute even in some small way to the (non-profit) org, that act decreases the probability that the org will fail, scaled (enormously) by how actively you engage. If you move closer to the org you sign up wit... (read more)

Most of the activities you propose increase the cost (non monetary) of cryonics to me. If I actively engage in cryonics organizations, it becomes more likely to work, but I'd rather spend the time playing music. Similarly, does it take more than an additional $300/year to double my chances of revival? If not, it's still not worth it for me. Treating it as a charity make sense to me. Me signing up helps other people who sign up. Unfortunately for cryonics, it has tough competition as a charity. I don't think it comes anywhere close to givewell's top charity.
I don't know, what do you think? It seems to me that if you can figure out some way to help the brain preservation foundation (http://www.brainpreservation.org/) develop a non-cryogenic (i.e., room temp) method of preservation, it could much more than double your chances. Looking back on it, which activity has had more benefit over its lifespan, the development of antibiotics in the 1930's, or the development and enactment of the US welfare state in the 1930s? Which one cost more money?
I don't understand how this is relevant. The money I donate (1) does not go to the US welfare state. Do you think that $1K spent on cryonics saves an expected life? If not, I don't think it beats village reach as a charity. (1) I take donation and charity seriously. I believe I should earn as much money as I can so that I can give away as much as I can. In 2010 my wife and I gave away $45K, spending $22K on us.
OK, I update my "surprise" based on this info that you donate so much to charity. Good stuff. I was using that as an example of how 1) donations to well-meaning and efficacious current charities can have unintended negative consequences in the long run (i.e., make people dependent), and 2) investments in scientific research (including the societal infrastructure to support it) tend to pay off great dividends in the long run.
I've never heard anybody claim welfare was "efficacious." Comparing public health charities to welfare rather than antibiotics seems pretty goofy to me.
I agree that plastification or something existing would more than double my chances. But a lot of work needs to go into that. I'm not at all convinced that me giving them $300 would come close to doubling my chances.
I agree that $300, with no concomitant time investment, would probably not be enough. I guess I'm just surprised that a (smart) person could read all of this information about a potentially hugely transformative technology, assign such a low probability (20%) to the likelihood that "not all of what makes you you is encoded in the physical state of the brain," and still just generally not care much and prefer to go play music instead. I just don't get it. Maybe I'm weird.
It seems unlikely to me that I can have a large effect on the probabilities; they will probably stay very small even if I put in a lot of work. So I think time spent on music will make me happier than time spent on cryonics.

There has been some discussion on this thread about who would revive you once you were cryopreserved, and how they would pay for it.

This is covered in the Alcor FAQ (which is really excellent, and well worth browsing):

Q: Who will revive the patients?

A: The short answer is "Alcor will revive them."

The third item in Alcor's mission statement is: "Eventually restore to health all patients in Alcor's care."

Reviving the patients is also required by Alcor's contracts with members: "When, in Alcor's best good faith judgement, it is determ... (read more)

I think there's a decent chance that even if some of us are revived we won't have any ability to create anywhere near the economic value needed to revive others. We'd probably be pretty useless to the future, so that if reviving people is at all expensive the people revived first would not be able to continue the process.

If an American signs up for cryonics and pays their ~$300/year, what are their odds of being revived?

Don't know, "sufficiently small" about covers it. If you have a better ~$300/year bet to gain the whole future, this question would be worth answering.


"the payoff is really high

and more "the payoff is in a different class to anything else that's within a modest salary's reach".

Like, if there were no computers, and everyone did math in their head, and we were still stuck bartering between villages - cryonics is not a sho... (read more)

The research suggests that winning the lottery, etc. doesn't tend to make you happier long-term. What makes you think that the years you spend with trucks and gasoline are going to be significantly better than the years you spent bartering between villages? I'm not aware of any evidence that happiness has grown to a "different class to anything else" in the history of human civilization. The percent of people in seriously messed up situations may have dropped, but the standard of happiness for a well-off moderate-status individual doesn't seem like it's changed that extremely. (Note that I am referring to happiness, not "standard of living"; it's easy to imagine being miserable back in 50 AD now that you've experienced the future, but that doesn't mean everyone back then was miserable just because they lacked World of Warcraft) Even if you just value years lived, we're only talking two or three orders of magnitude here. "Cryonics will revive you" is an easier claim than "Cryonics will revive you and keep you alive for another thousand years", which is still easier than "Cryonics will revive you and give you a perfect Fun Theory utopia where you live for $MAX_PLEASANT_LIFESPAN" I think trying to turn cryonics in to a Pascal's Wager really doesn't do a lot to convince people to sign up. I also think it relies on hooks that most people don't really have - most people seem to value "average quality of life" a lot more than the actual length.
That improvements generally do not translate to improved happiness in humans, a la is in my mind a serious flaw, right up there with scope insensitivity. To me, arguing that cryonics isn't worth it because humans can't really feel improvements in quality of life is like arguing that the Make-a-Wish foundation and VillageReach are of equal value as charities because humans can't really feel the difference. Sure, maybe we can't, but... VillageReach is still better than Make-a-Wish, and future life (conditioned on being revived) is better than present life.
You're committing fallacious reasoning here. Just because I'm saying "increased future happiness is not a good argument for cryonics", does NOT mean that I think there are no good arguments for cryonics. I just think that yours is not one of them. I'm specifically critiquing your phrasing of "the payoff is in a different class to anything else". You can make some additional assumptions that lead to "Cryonics + Fun Theory Utopia", but it's fundamentally less likely to occur than just "Cryonics" by itself. Equally, million year lifespans are less likely than thousand year lifespans. Cryonics, by itself, is not in a different class; it's just waking up from a coma after years of being clinically dead.

The fact that some of Harvard's brain collection just thawed makes me think it's likely to eventually happen to other institutions, too.

Alcor seems to think of frozen brains as having high moral weight, similar to living people. I don't think Harvard values them anywhere near as much, so it may not indicate so much that they screwed up.

0.30 No one is interested in my brain's information

0.40 It is too expensive to extract my brain's information

I always assumed that the cryonics companies would pay for that with the extra interest. I suppose the second one could still be true if it takes a noticeable portion of the economy.

I would put those at significantly more likely than even the pessimistic author had. After all, where on earth would the money come from to bring you back?

Imagine that your favorite cryonics company (Alcor/TransTime/CryonicsInstitute/etc) existed back in 1911 and has finally discovered how to thaw people, 100 years later. They magically came across the process back then and there's warehouses full of people who can come back if the company spends a modest sum of $50,000 on the revival (which is a way, way, way, way low estimate). Their contracts back in 1911 were exactly the same as current ones.

The first couple would get thawed out as proof the tech works; the next few would be celebrities or people who have still-surviving rich family; after that nobody else would get thawed. Why would they? Nobody's going to care about the rights of someone 100 years dead. There wouldn't be a huge interest group interested in bringing back hundred year old corpses. Modern society wouldn't want these people, who are racist, sexist, superstitious, have zero job skills, have zero life skills, and would cost enormous amounts to social services before they're productive members of society (if ... (read more)

Not just some stranger; as you point out they'll definitely do that. What I am skeptical they will do is revive and support millions of such people who are all needy in the same boring and tedious ways.
Yes, people might not try to thaw random people from a hundred years ago. But people who have been unthawed will have some interest in unthawing other people they know. Moreover, each set of cryopatiens will want to unthaw other people they knew. And the most recent cryopatients who are preserved will be people who still have living familes who will have an interest in them. I think you overestimate the problems.
Alcor doesn't set aside funds for thawing. Even if Alcor wanted to, they wouldn't be able to bring you back until things were post scarcity. The money you pay goes to 1) Paying to prepare/transport you when you die, 2) Freezing you, 3) Keeping you frozen. That's it. They're basically banking on a post-scarcity society to handle paying for your resurrection. The saved $25,000 is definitely not enough to pay for the medical procedure and a nice new vat-form body unless we're seriously on the way to being post-scarcity anyways. Maybe if you've got still-living family they could all pool their entire earnings for a couple decades to bring back Grandpa, but I still wouldn't count on it. I definitely wouldn't count on a chain of thawed people to spend decades of work each step to get the money to thaw me out.
Go to http://www.alcor.org/Library/html/CostOfCryonics.html and search for the header "Determining Safety Reserves For Long-Term Care". Specifically: "Clearly some additional money held in trust is needed to provide for contingent costs such as moving the patients, moving Patient Care Fund (PCF) money overseas in the event of inflation, and covering the costs of revival."
That's a good point but it makes more sense as a comment to Daniel above. I didn't say anything about the cryonics orgs thawing people.
The money would come from interest. Presumably, the company would be set up in such a way that they can't use the money for thawing until they thaw you out. If Alcor doesn't set aside money, and doesn't let the money set aside for freezing that doesn't end up being used get used as such, I'd suggest either finding a place that does, or just setting up a trust yourself. Make it accrue interest until it reaches a given amount accounting for deflation, and donate the interest to charity or something, then make it pay off to Alcor, or whoever thaws you, when they do. If these people really aren't planning ahead that much, should some of us get together and start a fund like that? That way, you hire a company to freeze you, and join one of the funds to thaw you. A few other ways you could get thawed: A charity starts thawing people. People who have been thawed will tend to be willing to donate. At some point, the cost of thawing gets low enough compared to keeping frozen, and the interest rate reduces enough, that it becomes cheaper to thaw people than to keep them frozen. This won't work if the interest rate falls enough to make the cryonics companies go out of business before that's possible. On the other hand, if they figure out how to thaw people before that happens, the government will likely step in to keep them from dying.
That's not quite how interest rates work. To put it another way, the $25,000 Alcor has in interest will end up as $25,925. Inflation will bring this down to $25,146. Which means that Alcor can afford to spend about $150 dollars each year keeping you frozen before it starts cannibalizing the saved money. That strikes me as rather low, but according to Alcor they've budgeted to keep you frozen indefinitely. Realistically, I'd expect zero money left over as interest. Charities strike me as unlikely. We already have trouble saving African children for $500 a life; I doubt donors would give hundreds of thousands of dollars per life to thaw out people who lived full lives already. Hell, I want to get cryonics and I'd still donate to a more efficient charity. The only way you'd get thawed is if thawing costs + doctor costs + the cost for a new body + physical therapy costs ended up at roughly what you have saved now in real purchasing power. That means roughly, 7000 big macs, the average price of a new car, or about half a year's work. And if we're at the point where the average family can afford multiple back-up bodies (like we have multiple cars today), we're probably damn near to a post-scarcity society anyways. I mean, we're talking about a future where it's cheaper to upload your consciousness to the office and inhabit a temporary shell while you work than it is to drive (though at that point I doubt labor would look anything like what we're used to). If that doesn't qualify as post-friendly-singularity than I don't know what does.
Savings accounts aren't exactly known for having a high return on investment. Accept a little risk, and spread out the investment so it won't all get lost. Also, keep enough extra to survive recessions. The people saved by it can't easily donate to it. People thawed out can.
What matters is what alcor etc are actually doing. Alcor has this on their website on the distribution of their investment fund: This doesn't look very risky, which is good in that they're unlikely to lose it but bad in that they're unlikely to do much above inflation in the long term.
Did they not mention how much interest they've been getting? From that link: They understand that the money is supposed to eventually pay for you revival. But as you seemed to show, they're likely being stupid with it so it won't be there.
Yes: "The Investment Account had a total annual return of 17.01% for 2009 and 6.18% for 2010". Which is well above inflation. Though I think the market as a whole also might have done well over that period? I don't know enough about what they are doing or about what is good to say whether they are being stupid. But if they are being conservative, as trusts and foundations tend to, then there is a good chance they won't make much if any money in the long term.
Keeping people frozen is cheap: you just need to top up the liquid nitrogen once in a while to compensate for evaporation; and I guess that as they make better and better dewars and better and better technology for liquefying nitrogen, the storage prices per year will fall even more.
Exponential economic growth can't continue forever, which would suggest that the interest rate will fall arbitrarily low, so the cost of keeping someone frozen forever will increase. But yeah, I think significantly underestimated the time until it would be worth while. Come to think of it, there might be a point where it's cheaper to wake you and then put you in debt for a while, but that's a legal and ethical tricky area unless the user signs a contract before-hand. Edit: I should probably practice being a bit more straightforward with admitting errors. You are right. I was wrong.

Too high:

You mess up the paperwork, either for cryonics or life insurance

Some law is passed that prohibits cryonics (before you're even dead)

Not all of what makes you you is encoded in the physical state of the brain

All people die (nuclear war? comet strike? nanotech?)

The technology is never developed to extract the information

It is too expensive to extract my brain's information

Running people in simulation is outlawed

It is too expensive to run me in simulation (if we get this far I expect cheap powerful computers)

Far too low:

You die suddenly or in a

... (read more)
What if we add in "your ugh field around immediate paperwork is bigger than the one around distant death"? Speaking from an empirical sample of one, .03 is far too low in that case.
OK, I thought from how it was spoken about that the category was for an unknown error causing a problem after the fact. If it's for the ugh field, it's too low, if it's for an undiscovered error causing problems, it's too high.
Do you have better numbers? Ideally with reasons why you think mine are too low or too high?
Other people have done it. You fill in blanks. It just seems too high. It would be difficult to block someone with such a law because one could always be transported. Will Federal laws be passed in the US, and Canada? Probably not. US, Canada, and Anguilla? No chance. What are the other options? Sure, if I had a wound to my stomach I might "feel anxiety" differently, or something. Nuclear war would not kill everyone. Comet strike defenses are getting better and the risk is low. Nanotech...factory produced things will be more efficient than self-replicators, I do not expect self-replicators to be where investment is put. It is easier to break things than fix them, self replicators are breaking things not too hard to break, as they are practically alive. Humans with no technology survived the ice age. Someone's surviving whatever we do in a bomb shelter with a million cans of tuna, or on Tasmania, or something. Take thin slices, print it. Conceptually it's not hard, even if technologically impossible. It doesn't seem outlandish or as a thing in kind that must be invented, like nanotechnology is. Things get cheap. Weirdly specific, but you could be revived as well. Just go slower, and run on a Pentium III at one second per decade or whatever. Far too low: I didn't look at actuarial tables, but head trauma is not a good thing, more than time is involved. Much probability mass taken from "All people die" (you had it at .3, I have it about .01), but still more than your .2+.3. More like .8. Societies fail. They just do. That's what they do. If the society isn't basically stable, it will change until it eventually dies. The society will have institutions poorly designed for past circumstances (as overreactions to even older circumstances) persist and be less and less appropriate. The society will consume resources until they are gone. The society will have cooperative morals decay and become a mass of individuals. Societies...for these things death is natural mo
Not anymore. Societies fall, but they fall a fixed distance before they restructure and recover, and they start a little higher every year.
I look at the failed states index and it makes me pessimistic.
If you really want to get pessimistic, read Collapse, by Jared Diamond. It shows how a complex, apparently functioning society can totally fall apart in way less time than you might expect.
I read that book a while ago. My memory is that the societies he examined were in very fragile environments, much more fragile than most places people are.
He argues that how fragile an environment is, depends on the demands placed on it by it inhabitants. The Mayan Yucatan, Haiti, and Rwanda were not particularly fragile, but every place has a limit.
You're right; I was just remembering the easter island and greenland bits.
Many of those failed states are states which have been failed for quite a long time. It is extremely rare for a state to be in good shape and then get to very bad shape.
It's not the ones at the bottom I'm concerned with. Many of the ones rated "Moderate" don't seem stable for our purposes here, which are slightly different than the list's compilers'. We want to see countries that are unlikely to have a sufficiently bad shock over the next century and a half or so, the index is concerned with related but different things including refugees and factionalization of elites. A good example of what I'm talking about is Kuwait. As far as I can tell it deserves its place in the same category as the United States, near the bottom of it with the US near the top. But its geographical position makes it extremely unreliable as a possibly stable place for the next few centuries.

The choice to suspend yourself is strictly personal and highly speculative at best despite what you might hear from the various organizations out there or other "true believers". The honest organizations will tell you there are no guarantees and the process is entirely speculative, however if you don't have yourself frozen upon "deanimation" (their word for death) there's a 100% certainty you will not be "reanimated". I first learned about cryonics preservation in 1968 when the movement's founder Robert C.W. Ettinger appeared with Johnny Carson on the Ton... (read more)

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I really like that you did this, jkaufman - it's good to see a couple breakdowns like this. However, I think this would be best setup as the chance of post-cryonics disasters happening on a yearly basis, so you could modify the final outcome based on a prediction of how long it will take for reviving crynoics patients to be viable. This is harder to do, obviously, but I think it would give a better outcome. The chance of some X-risk before revival are greater if you expect to be preserved for 500 years than if you think we'll be able to revive cryonics patients in 100 years.

If an American signs up for cryonics and pays their ~$300/year, what are their odds of being revived?

This may just be my own intuition running away on me, but it seems like there are two different answers to that question.

In an absolute sense (as in, percentage of everett branches where you are revived from cryonics), the chances are probably pretty slim.

However, in a subjective sense. ("You" experience waking up from cryonics), the chances seem near certain. It's not like you'd be aware of any of the universes where you weren't revived, after all.

Doesn't this same argument say that the chances are certain that some branch of you keeps happening not to die anyway?
Not really. I think there is a difference betwween your consciousness existing in a branch where the casual chains leading to its destruction merely haven't reached your senses yet, and your brain existing in an unchanging state for a long period of time that would stretch the possible restoration of "you" over all branchings forward from the time of successful preservation. Your consciousness not "running" at all seems like a very different thing from it merely not knowing which branch(s) it is "running" in.

I think only a tiny minority of lesswrong readers, believe in cryopreservation. If people genuinely believed in it then they would not wait until they were dying to preserve themselves, since the cumulative risk of death or serious mental debilitation before cryopreservation would be significant, the consequence is loss of (almost) eternal life, while by early cryopreservation all they have to lose is their current, finite life, in the "unlikely" event that they are not successfully reanimated. If people were actually trying to preserve themselve... (read more)

Humans are not totally rational creatures. There are a lot of people who like the idea of cryonics but never sign up until it is very late. This isn't a sign of a lack of "belief"(although Aris correctly notes below that that term isn't well-defined) but rather a question of people simply going through the necessary effort. Many humans have ugh fields around paperwork, or don't want to send strong weirdness signals, or are worried about extreme negative reactions from their family members. Moreover, there's no such thing as "almost" eternal life. 10^30 is about as far from infinity as 1 is. What does however matter is that there are serious problems with the claim that one would get infinite utility from cryonics. There have been some actually extremely tragic cases involving people with serious terminal illnesse such as cancer having to wait until they died (sometimes with additional brain damage as a result). This is because the cryonics organizations are extremely weak and small. They don't want to risk their situation by being caught up in the American euthanasia debate. This is one of the weakest arguments against cryonics. First of all, some human predictions have been quite accurate. The main weakness comes from the fact that almost every single two-bit futurist feels a need to make predictions, almost every single one of which goes for narrative plausibility and thus has massive issues with burdensome details and the conjunction fallacy. In looking at any specific technology we can examine it in detail and try to make predictions about when it will function. If you actually think that humans really bad at making predictions, then the you shouldn't just say "we simply don't now" instead you should adjust your prediction to be less confident, closer to 50%. This means that if you assign a low probability to cryonics working you should update towards giving it an increased chance of being successful.
"The main weakness comes from the fact that almost every single two-bit futurist feels a need to make predictions, almost every single one of which goes for narrative plausibility and thus has massive issues with burdensome details and the conjunction fallacy." - no. The most intelligent and able forecasters are incapable of making predictions (many of them worked in the field of AI). Your argument about updating my probability upwards because I don't understand the future is fascinating. Can you explain why I can't use the precise same argument to say there is a 50% chance that Arizona will be destroyed by a super-bomb on January 1st 2018?
Yes. precisely because they suffer from the biases mentioned. Sure predicting the future is really tough. But it isn't helped by the presence of severe biases. It is important to realize that intelligent doesn't mean one is less likely to be subject to cognitive biases. Nor, does being an expert in a specific area render one immune- look at the classic conjunction fallacy study with the USSR invading Poland. It is true that even taking that into account predicting the future is really hard. But if one looks for signs of the obvious biases then most predictions problems show up immediately. Well, you should move your uncertainty in the direction of 50% probably. But there's no reason to say exactly 50%. That's stupid. Your starting estimate for probability of such an event happening is really small, so the overconfidence adjustment won't be that large and will likely still keep the probability negligible after the adjustment. This isn't like cryonics at all. First, the relevant forecast time for cryonics working is a much longer period and it extends much farther into the future than 2018. That means the uncertainty from prediction the future has a much larger impact. Also, people are actively working on the relevant technologies and have clear motivations to do so. I don't in contrast even know what exactly a "super-bomb" is or why someone would feel a need to use it to destroy Arizona. So the adjustments for predictive uncertainty and general overconfidence should move cryonics a lot closer to 50% than it should for your super-bomb example.
I think you need to define your usage of the term "believe in" slightly better. Belief for what percentages of cryo success rate qualify for "belief in cryopreservation"? If you're talking about percentages over 90% -- indeed I doubt that a significant number of lesswrong readers would have nearly that much certainty in cryo success. But for any percentages below that, your arguments become weak to the point of meaningless -- for at that point it becomes reasonable to use cryopreservation as a last resort, and hope for advancements in technology that'll make cryopreservation surer -- while still insuring yourself in case you end up in a position that you don't have the luxury of waiting any more.
Belief is pretty unambiguous - being sure of (100% probability, like cogito ergo sum), or a strong trust (not nearly 90% probability is not belief). So it seems we are in agreement, you don't believe in it, and neither do most less wrong readers. I agree that based on that argument, whether the probability is 10^-1000 or 75%, is still up for debate.
If that's your definition of belief then it may not be that relevant. If I there's a game where someone roles a pair of fair six-sided dice and will give me five dollars if I can guess their sum, my best strategy is to guess 7 even though I don't by your definition believe that 7 will turn up. In this context this becomes a less than helfpul notation. Also, if this is what you meant, I'm a bit confused by why you brought it up. Many prominent cryonics proponents give estimates well below 90%. So what point were you trying to make?