Abnormal Cryonics

Getting back down to earth, there has been renewed interest in medical circles in the potential of induced hibernation, for short-term suspended animation. The nice trustworthy doctors in lab coats, the ones who get interviews on TV, are all reassuringly behind this, so this will be smoothly brought into the mainstream, and Joe the Plumber can't wait to get "frozed-up" at the hospital so he can tell all his buddies about it.

Once induced hibernation becomes mainstream, cryonics can simply (and misleadingly, but successfully) be explained as "hibernation for a long time."

Hibernation will likely become a commonly used "last resort" for many many critical cases (instead of letting them die, you freeze 'em until you've gone over their chart another time, talked to some colleagues, called around to see if anyone has an extra kidney, or even just sleep on it, at least.) When your loved one is in the fridge, and you're being told that there's nothing left to do, we're going to have to thaw them and watch them die, your next question is going to be "Can we leave them in the fridge a bit longer?"

Hibernation will sell people on the idea that fridges save lives. It doesn't have to be much more rational than that.

If you're young, you might be better off pushing hard to help that tech go mainsteam faster. That will lead to mainstream cryo faster than promoting cryo, and once cryo is mainstream, you'll be able to sign up for cheaper, probably better cryo, and more importantly, one that is integrated into the medical system, where they might transition me from hibernation to cryo, without needing to make sure I'm clinically dead first.

I will gladly concede that, for myself, there is still an irrational set of beliefs keeping me from buying into cryo. The argument above may just be a justification I found t avoid biting the bullet. But maybe I've stumbled onto a good point?

An interesting comparison I mentioned previously: the cost to Alcor of preserving one human (full-body) is $150,000. The recent full annual budget of SIAI is on the order of (edit:) $500,000.

I haven't yet read and thought enough about this topic to form a very solid opinion, but I have two remarks nevertheless.

First, as some previous commenters have pointed out, most of the discussions of cryonics fail to fully appreciate the problem of weirdness signals. For people whose lives don't revolve around communities that are supportive of such undertakings, the cost of signaled weirdness can easily be far larger than the monetary price. Of course, you can argue that this is because the public opinion on the topic is irrational and deluded, but the point is that given the present state of public opinion, which is impossible to change by individual action, it is individually rational to take this cost into account. (Whether the benefits ultimately overshadow this cost is a different question.)

Second, it is my impression that many cryonics advocates -- and in particular, many of those whose comments I've read on Overcoming Bias and here -- make unjustified assertions about supposedly rational ways to decide the question of what entities one should identify oneself with. According to them, signing up for cryonics increases the chances that at some distant time in the future, in which you'll otherwise probably be dead and gone, some entity will exist with which it is rational to identify to the point where you consider it, for the purposes of your present decisions, to be the same as your "normal" self that you expect to be alive tomorrow.

This is commonly supported by arguing that your thawed and revived or uploaded brain decades from now is not a fundamentally different entity from you in any way that wouldn't also apply to your present brain when it wakes up tomorrow. I actually find these arguments plausible, but the trouble is that they, in my view, prove too much. What I find to be the logical conclusion of these arguments is that the notion of personal identity is fundamentally a mere subjective feeling, where no objective or rational procedure can be used to determine the right answer. Therefore, if we accept these arguments, there is no reason at all to berate as irrational people who don't feel any identification with these entities that cryonics would (hopefully) make it possible to summon into existence in the future.

In particular, I personally can't bring myself to feel any identification whatsoever with some computer program that runs a simulation of my brain, no matter how accurate, and no matter how closely isomorphic its data structures might be to the state of my brain at any point in time. And believe me, I have studied all the arguments for the contrary position I could find here and elsewhere very carefully, and giving my utmost to eliminate any prejudice. (I am more ambivalent about my hypothetical thawed and nanotechnologically revived corpse.) Therefore, in at least some cases, I'm sure that people reject cryonics not because they're too biased to assess the arguments in favor of it, but because they honestly feel no identification with the future entities that it aims to produce -- and I don't see how this different subjective preference can be considered "irrational" in any way.

That said, I am fully aware that these and other anti-cryonics arguments are often used as mere rationalizations for people's strong instinctive reactions triggered by the weirdness/yuckiness heuristics. Still, they seem valid to me.

I think cryonics is used as a rationality test because most people reason about it from within the mental category "weird far-future stuff". The arguments in the post seem like appropriate justifications for choices within that category. The rationality test is whether you can compensate for your anti-weirdness bias and realize that cryonics is actually a more logical fit for the mental category "health care".

This post, like many others around this theme, revolves around the rationality of cryonics from the subjective standpoint of a potential cryopatient, and it seems to assume a certain set of circumstances for that patient: relatively young, healthy, functional in society.

I've been wondering for a while about the rationality of cryonics from a societal standpoint, as applied to potential cryopatients in significantly different circumstances; two categories specifically stand out, death row inmates and terminal patients.

This article cites the cost of a death row inmate (over serving a life sentence) to $90K. This is a case where we already allow that society may drastically curtail an individual's right to control their own destiny. It would cost less to place someone in cryonic suspension than to execute him, and in so doing we would provide a chance, however small, that a wrongful conviction could be reversed in the future.

As for terminal patients, this article says:

Aggressive treatments attempting to prolong life in terminally ill people typically continue far too long. Reflecting this overaggressive end-of-life treatment, the Health Care Finance Administration reported that about 25% of Medicare funds are spent in the last 6 months of life (about $68 billion in 2003 or $42,000 per dying patient). Actually, the last 6 months of a Medicare recipient's life consumes about $80,000 for medical services, since Medicare pays only 53% of the bill. Dying cancer patients cost twice the average amount or about $160,000.

These costs are comparable to that charged for cryopreservation. It seems to me that it would be rational (as a cost reduction measure) to offer patients diagnosed with a likely terminal illness the voluntary option of being cryopreserved. At worst, if cryonics doesn't work, this amounts to an "assisted suicide", something that many progressive groups are already lobbying for.

This comment is a more fleshed-out response to VladimirM’s comment.

This is commonly supported by arguing that your thawed and revived or uploaded brain decades from now is not a fundamentally different entity from you in any way that wouldn't also apply to your present brain when it wakes up tomorrow. I actually find these arguments plausible, but the trouble is that they, in my view, prove too much.

Whether cryonics is the right choice depends on your values. There are suggestions that people who don’t think they value revival in the distant future are mislead about their real values. I think it might be the complete opposite: advocation of cryonics completely missing what it is that people value about their lives.

The reason for this mistake could be that cryonics is such a new idea that we are culturally a step or two behind in identifying what it is that we value about existence. So people think about cryonics a while and just conclude they don’t want to do it. (For example, the stories herein.) Why? We call this a ‘weirdness’ or ‘creep’ factor, but we haven’t identified the reason.

When someone values their life, what is it that they value? When we worry about dying, we worry about a variety of obligations unmet (values not optimized), and people we love abandoned. It seems to me that people are attached to a network of interactions (and value-responsibilities) in the immediate present. There is also an element of wanting more experience and more pleasure, and this may be what cryonics advocates are over-emphasizing. But after some reflection, how do you think most people would answer this question: when it comes to experiencing 5 minutes of pleasure, does it matter if it is you or someone else if neither of you remember it?

A lot of the desperation we feel when faced with death is probably a sense of responsibility for our immediate values. We are a bundle of volition that is directed towards shaping an immediate network of experience. I don't really care about anything 200 years from now, and enjoy the lack of responsibility I feel for the concerns I would have if I were revived then. As soon as I was revived, however, I know I would become a bundle of volition directed towards shaping that immediate network of experience.

Considering what we do value about life -- immediate connections, attachments and interactions, it makes much more sense to invest in figuring out technology to increase lifespan and prevent accidental death. Once the technology of cryonics is established, I think that there could be a healthy market for people undergoing cryonics in groups. (Not just signing up in groups, but choosing to be vitrified simultaneously in order to preserve a network of special importance to them.)

Reason #6 not to sign up: Cryonics is not compatible with organ donation. If you get frozen, you can't be an organ donor.

The most common objections (most of them about the infeasibility of cryopreservation) are simply wrong.

Thus triggering the common irrational inference, "If something is attacked with many spurious arguments, especially by religious people, it is probably true."

(It is probably more subtle than this - When you make argument A against X, people listen just until they think they've matched your argument to some other argument B they've heard against X. The more often they've heard B, the faster they are to infer A = B.)

I told Kenneth Storey, who studies various animals that can be frozen and thawed, about a new $60M government initiative (mentioned in Wired) to find ways of storing cells that don't destroy their RNA. He mentioned that he's now studying the Gray Mouse Lemur, which can go into a low-metabolism state at room temperature.

If the goal is to keep you alive for about 10 years while someone develops a cure for what you have, then this room-temperature low-metabolism hibernation may be easier than cryonics.

(Natural cryonics, BTW, is very different from liquid-nitrogen cryonics. There are animals that can be frozen and thawed; but most die if frozen to below -4C. IMHO natural cryonics will be much easier than liquid-nitrogen cryonics.)

I object to many of your points, though I express slight agreement with your main thesis (that cryonics is not rational all of the time).

"Weird stuff and ontological confusion: quantum immortality, anthropic reasoning, measure across multiverses, UDTesque 'decision theoretic measure' or 'probability as preference', et cetera, are not well-understood enough to make claims about whether or not you should even care about the number of 'yous' that are living or dying, whatever 'you' think you are."

This argument basically reduces to, once you remove the aura of philosophical sophistication, "we don't really know whether death is bad, so we should worry less about death". This seems to me absurd. For more, read eg. http://yudkowsky.net/other/yehuda .

"If people believe that a technological singularity is imminent, then they may believe that it will happen before they have a significant chance of dying:"

If you assume the median date for Singularity is 2050, Wolfram Alpha says I have a 13% chance of dying before then (cite: http://www.wolframalpha.com/input/?i=life+expectancy+18yo+male), and I'm only eighteen.

"A person might find that more good is done by donating money to organizations like SENS, FHI, or SIAI3 than by spending that money on pursuing a small chance of eternal life."

If you already donate more than 5% of your income or time to one of these organizations, I'll buy that. Otherwise (and this "otherwise" will apply to the vast majority of LW commenters), it's invalid. You can't say "alternative X would be better than Y, therefore we shouldn't do Y" if you're not actually doing X.

"Calling non-cryonauts irrational is not productive nor conducive to fostering a good epistemic atmosphere"

Why? Having a good epistemic atmosphere demands that there be some mechanism for letting people know if they are being irrational. You should be nice about it and not nasty, but if someone isn't signing up for cryonics for a stupid reason, maintaining a high intellectual standard requires that someone or something identify the reason as stupid.

"People will not take a fringe subject more seriously simply because you call them irrational for not seeing it as obvious "

This is true, but maintaining a good epistemic atmosphere and getting people to take what they see as a "fringe subject" seriously are two entirely separate and to some extent mutually exclusive goals. Maintaining high epistemic standards internally requires that you call people on it if you think they are being stupid. Becoming friends with a person who sees you as a kook requires not telling them about every time they're being stupid.

"Likewise, calling people irrational for having kids when they could not afford cryonics for them is extremely unlikely to do any good for anyone."

If people are having kids who they can't afford (cryonics is extremely cheap; someone who can't afford cryonics is unlikely to be able to afford even a moderately comfortable life), it probably is, in fact, a stupid decision. Whether we should tell them that it's a stupid decision is a separate question, but it probably is.

"One easily falls to the trap of thinking that disagreements with other people happen because the others are irrational in simple, obviously flawed ways."

99% of the world's population is disagreeing with us because they are irrational in simple, obviously flawed ways! This is certainly not always the case, but I can't see a credible argument for why it wouldn't be the case a large percentage of the time.

I don't know if this is a self-defense mechanism or actually related to the motives of those promoting cryonics in this group, but I've always taken the "you're crazy not to be signed up for cryonics" meme to be intentional overstatement. If the intent is to remind me that things I do may later turn out to be not just wrong, but extremely wrong, it works pretty well.

It's a good topic to explore agreement theory, as different declared-intended-rationalists have different conclusions, and can talk somewhat dispassionately about such disagreement.

I have trouble believing that anyone means it literally, that for most humans a failure to sign up for cryonics at the earliest opportunity is as wrong as believing there's a giant man in the sky who'll punish or reward you after you die.

On a side note, speaking of "abnormal" and cryonics, apparently Britney Spears wants to sign up with Alcor: http://www.thaindian.com/newsportal/entertainment/britney-spears-wants-to-be-frozen-after-death_100369339.html

I think this can be filed under "any publicity is good publicity".

I'm not sure if this is the right place to ask this or even if it is possible to procure the data regarding the same, but who is the highest status person who has opted for Cryonics? The wealthiest or the most famous..

Having high status persons adopt cryonics can be a huge boost to the cause, right?

Probably my biggest concern with cryonics is that if I was to die at my age (25), it would probably be in a way where I would be highly unlikely to be preserved before a large amount of decay had already occurred. If there was a law in this country (Australia) mandating immediate cryopreservation of the head for those contracted, I'd be much more interested.

I get the feeling that this discussion [on various threads] is fast becoming motivated cognition aiming to reach a conclusion that will reduce social tension between people who want to sign up for cryo and people who don't. I.e. "Surely there's some contrived way we can leverage our uncertainties so that you can not sign up and still be defensibly rational, and sign up and be defensibly rational".

E.g. No interest on reaching agreement on cryo success probabilities, when this seems like an absolutely crucial consideration. Is this indicative of people who genuinely want to get to the truth of the matter?

EDIT: Nick Tarleton makes a good point in reply to this comment, which I have moved to be footnote 2 in the text.

As yet another media reference. I just rewatched the Star Trek TNG episode 'the neutral zone' which deals with recovery of 3 frozen humans from our time. It was really surprising to me how much disregard for human life is shown in this episode. "Why did you recover them, they were already dead". "Oh bugger, now that you revived/healed them we have to treat them as humans". Also surprising is how much insensibility in dealing with them is shown. When you awake someone from an earlier time you might send the aliens and the robots out of the room.

Question for the advocates of cryonics: I have heard talk in the news and various places that organ donor organizations are talking about giving priority to people who have signed up to donate their organs. That is to say, if you sign up to be an organ donor, you are more likely to receive a donated organ from someone else should you need one. There is some logic in that in the absence of a market in organs; free riders have their priority reduced.

I have no idea if such an idea is politically feasible (and, let me be clear, I don't advocate it), however, were it to become law in your country, would that tilt the cost benefit analysis away from cryonics sufficiently that you would cancel your contract? (There is a new cost imposed by cryonics: namely that the procedure prevents you from being an organ donor, and consequently, reduces your chance of a life saving organ transplant.)

Thanks for this post. I tend to lurk, and I had some similar questions about the LW enthusiasm for cryo.

Here's something that puzzles me. Many people here, it seems to me, have the following preference order:

pay for my cryo > donation: x-risk reduction (through SIAI, FHI, or SENS) > paying for cryo for others

Of course, for the utilitarians among us, the question arises: why pay for my cryo over risk reduction? (If you just care about others way less than you care about yourself, fine.) Some answer by arguing that paying for your own cryo maximizes x-risk reduction better than the other alternatives because of its indirect effects. This reeks of wishful thinking and doesn't fit well with the preference order above. There are plenty of LWers, I assume, who haven't signed up for cryo, but would if someone else would pay the life insurance policy. If you really think that paying for your own cryo maximizes x-risk reduction, shouldn't you also think that getting others signed up for cryo does as well? (There are some differences, sure. Maybe the indirect effects aren't as substantial if others don't pay their own way in full. But I doubt this justifies the preference.) If so, it would seem that rather than funding x-risk reduction through donating to these organizations, you should fund the cryo preservation of LWers and other willing people.

So which is it utilitarians: you shouldn't pay for your own cryo or you should be working on paying for the cryo of others as well?

If you think paying for cryo is better, want to pay for mine first?

If people believe that a technological singularity is imminent, then they may believe that it will happen before they have a significant chance of dying

This only makes sense given large fixed costs of cryonics (but you can just not make it publicly known that you've signed up for a policy, and the hassle of setting one up is small compared to other health and fitness activities) and extreme (dubious) confidence in quick technological advance, given that we're talking about insurance policies.

Not signing up for cryonics is a rationality error on my part. What stops me is an irrational impulse I can't defeat: I seem to subsonsciously value "being normal" more than winning in this particular game. It is similar to byrnema's situation with religion a while ago. That said, I don't think any of the enumerated arguments against cryonics actually work. All such posts feel like they're writing the bottom line in advance.

I'm new here, but I think I've been lurking since the start of the (latest, anyway) cryonics debate.

I may have missed something, but I saw nobody claiming that signing up for cryonics was the obvious correct choice -- it was more people claiming that believing that cryonics is obviously the incorrect choice is irrational. And even that is perhaps too strong a claim -- I think the debate was more centred on the probability of cyronics working, rather than the utility of it.

Is it so irrational to not fear death?

I am not liking long term cryonics for the following reasons: 1) If an unmodified Violet would be revived she would not be happy in the far future 2) If a Violet modified enough would be revived she would not be me 3) I don't place a large value on there being a "Violet" in the far future 4) There is a risk of my values and the values of being waking Violet up being incompatible, and avoiding possible "fixing" of brain is very high priority 5) Thus I don't want to be revived by far-future and death without cryonics seems a safe way for that

Just noting that buried in the comments Will has stated that he thinks the probability that cryo will actually save your life is one in a million -- 10^-6 -- (with some confusion surrounding the technicalities of how to actually assign that and deal with structural uncertainty).

I think that we need to iron out a consensus probability before this discussion continues.

Edit: especially since if this probability is correct, then the post no longer makes sense...

This post seems to focus too much on Singularity related issues as alternative arguments. Thus, one might think that if one assigns the Singularity a low probability one should definitely take cryonics. I'm going to therefore suggest a few arguments against cryonics that may be relevant:

First, there are other serious existential threats to humans. Many don't even arise from our technology. Large asteroids would be an obvious example. Gamma ray bursts and nearby stars going supernova are other risks. (Betelgeuse is a likely candidate for a nearby supernova making our lives unpleasant. If current estimates are correct there will be substantial radiation from Betelgeuse in that situation but not so much as to wipe out humanity. But we could be wrong.)

Second, one may see a high negative utility if one gets cryonics and one's friends and relatives do not. The abnormal after death result could substantially interfere with their grieving processes. Similarly, there's a direct opportunity cost to paying and preparing for cryonics.

The above argument about lost utility is normally responded to by claiming that the expected utility for cryonics is infinite. If this were actually the case, this would be a valid response.

This leads neatly to my third argument: The claim that my expected utility from cryonics is infinite fails. Even in the future, there will be some probability that I die at any given point. If that probability is never reduced below a certain fixed amount, then my expected life-span is still finite even if I assume cryonics succeeds. (Fun little exercise, suppose that my probability of dying is x on any given day. What is my expected number of days of life? Note that no matter how small x is, as long as x>0, you still get a finite number). Thus, even if one agrees that an infinite lifespan can give infinite utility, it doesn't follow that cryonics gives an expected value that is infinite. (Edit: What happens in a MWI situation is more complicated but similar arguments can be made as the fraction of universes where you exist declines at a geometric rate so the total sum of utility over all universes is still finite)

Fourth, it isn't even clear that one can meaningfully talk about infinite utility. For example, consider the situation where you are given two choices (probably given to you by Omega because that's the standard genie equivalent on LW). In one of them, you are guaranteed immortality with no costs. In the other you are guaranteed immortality but are first tortured for a thousand years. The expected utility for both is infinite, but I'm pretty sure that no one is indifferent to the two choices. This is closely connected to the fact that economists when using utility make an effort to show that their claims remain true under monotonic transformations of total utility. This cannot hold when one has infinite utility being bandied about (it isn't even clear that such transformations are meaningful in such contexts). So much of what we take for granted about utility breaks down.

It would be interesting to see a more thorough analysis of whether the "rational" objections to cryo actually work.

For example, the idea that money is better spent donated to some x-risk org than to your own preservation deserves closer scrutiny. Consider that cryo is cheap ($1 a day) for the young, and that getting cryo to go mainstream would be a strong win as far as existential risk reduction is concerned (because then the public at large would have a reason to care about the future) and as far as rationality is concerned.

Here's another possible objection to cryonics:

If an Unfriendly AI Singularity happens while you are vitrified, it's not just that you will fail to be revived - perhaps the AI will scan and upload you and abuse you in some way.

"There is life eternal within the eater of souls. Nobody is ever forgotten or allowed to rest in peace. They populate the simulation spaces of its mind, exploring all the possible alternative endings to their life." OK, that's generalising from fictional evidence, but consider the following scenario:

Suppose the Singularity develops from an AI that was initially based on a human upload. When it becomes clear that there is a real possibility of uploading and gaining immortality in some sense, many people will compete for upload slots. The winners will likely be the rich and powerful. Billionaires tend not to be known for their public-spirited natures - in general, they lobby to reorder society for their benefit and to the detriment of the rest of us. So, the core of the AI is likely to be someone ruthless and maybe even frankly sociopathic.

Imagine being revived into a world controlled by a massively overclocked Dick Cheney or Vladimir Putin or Marquis De Sade. You might well envy the dead.

Unless you are certain that no Singularity will occur before cryonics patients can be revived, or that Friendly AI will be developed and enforced before the Singularity, cryonics might be a ticket to Hell.

Good post. People focus only on the monetary cost of cryonics, but my impression is there are also substantial costs from hassle and perceived weirdness.

One easily falls to the trap of thinking that disagreements with other people happen because the others are irrational in simple, obviously flawed ways. It's harder to avoid the fundamental attribution error and the typical mind fallacy, and admit that the others may have a non-insane reason for their disagreement.

Harder, not harder, but which is actually right? This is not about signaling one's ability to do the harder thing.

The reasons you listed are not ones moving most people to not sign up for cryonics. Most people, as you mention at the beginning, simply don't take the possibility seriously enough to even consider it in detail.

I think cryonics is a great idea and should be part of health care. However, $50,000 is a lot of money to me and I'm reluctant to spend money on life insurance, which except in the case of cryonics is almost always a bad bet.

I would like my brain to be vitrified if I am dead, but I would prefer not to pay $50,000 for cryonics in the universes where I live forever, die to existential catastrophe, or where cryonics just doesn't work.

What if I specify in my (currently non-existent) cryonics optimized living will that up to $100,000 from my estate is to be used to pay for cryonics? It's not nearly as secure as a real cryonics contract, but it has the benefit of not costing $50,000.

I'm surprised that you didn't bring up what I find to be a fairly obvious problem with Cryonics: what if nobody feels like unthawing you? Of course, not having followed this dialogue I'm probably missing some equally obvious counter to this argument.

Hi, I'm pretty new here too. I hope I'm not repeating an old argument, but suspect I am; feel free to answer with a pointer instead of a direct rebuttal.

I'm surprised that no-one's mentioned the cost of cryonics in relation to the reduction in net human suffering that could come from spending the money on poverty relief instead. For (say) USD $50k, I could save around 100 lives ($500/life is a current rough estimate at lifesaving aid for people in extreme poverty), or could dramatically increase the quality of life of 1000 people (for example, cataract operations to restore sight to a blind person are around $50).

How can we say it's moral to value such a long shot at elongating my own life as being worth more than 100-1000 lives of other humans who happened to do worse in the birth wealth lottery than I did?

Another argument against cryonics is just that it's relatively unlikely to work (= lead to your happy revival) since it requires several things to go right. Robin's net present value calculation of the expected benefits of cryonic preservation isn't all that different from the cost of cryonics. With slightly different estimates for some of the numbers, it would be easy to end up with an expected benefit that's less than the cost.

et cetera, are not well-understood enough to make claims about whether or not you should even care about the number of 'yous' that are living or dying, whatever 'you' think you are.

This argument from confusion doesn't shift the decision either way, so it could as well be an argument for signing up, or against signing up; similarly for immediate suicide, or against that. On the net, this argument doesn't move, because there is no default to fall off to once you get more confused.

I am kind of disturbed by the idea of cryonics. Wouldn't it be theoretically possible to prove they don't work, assuming that they really don't. If the connections between neurons are lost in the process, then you have died.

Interesting post, but perhaps too much is being compressed into a single expression.

The niceness and weirdness factors of thinking about cryonics do not actually affect the correctness of cryonics itself. The correctness factor depends only on one's values and the weight of probability.

Not thinking one's own values through sufficiently enough to make an accurate evaluation is both irrational and a common failure mode. Miscalculating the probabilities is also a mistake, though perhaps more a mathematical error than a rationality error.

When these are the reasons for rejecting cryonics, then that rejection is obviously incorrect.

That said, you are quite correct to point out that differing values are not automatically a rationality failure, and it is definitely good to consider the image problem associated with the niceness issues.

Perhaps the niceness and weirdness ought to not be jumbled together with the correctness evaluation question.

I have been heavily leaning towards the anti-cryonics stance at least for myself with the current state of information and technology. My reasons are mostly the following.

I can see it being very plausible that somewhere along the line I would be subject to immense suffering, over which death would have been a far better option, but that I would be either potentially unable to take my life due to physical constraints or would lack the courage to do so (it takes quite some courage and persistent suffering to be driven to suicide IMO). I see this as analogous to a case where I am very near death and am faced with the two following options. (a) Have my life support system turned off and die peacefully.

(b) Keep the life support system going but subsequently give up all autonomy over my life and body and place it entirely in the hands of others who are likely not even my immediate kin. I could be made to put up with immense suffering either due to technical glitches which are very likely since this is a very nascent area, or due to willful malevolence. In this case I would very likely choose (a).

Note that in addition to prolonged suffering where I am effectively incapable of pulling the plug on myself, there is also the chance that I would be an oddity as far as future generations are concerned. Perhaps I would be made a circus or museum exhibit to entertain that generation. Our race is highly speciesist and I would not trust the future generations with their bionic implants and so on to even necessarily consider me to be of the same species and offer me the same rights and moral consideration.

Last but not the least is a point I made as a comment in response to Robin Hanson's post. Robin Hanson expressed a preference for a world filled with more people with scarce per-capita resources compared to a world with fewer people with significantly better living conditions. His point was that this gives many people the opportunity to "be born" who would not have come into existence. And that this was for some reason a good thing.

I couldn't care less if I weren't born. As the saying goes, I have been dead/not existed for billions of years and haven't suffered the slightest inconvenience. I see cryonics and a successful recovery as no different from dying and being re-born. Thus I assign virtually zero positives to being re-born, while I assign huge negatives to 1 and 2 above. This is probably related to the sense of identity mentioned in this post.

We are evolutionarily driven to dislike dying and try to postpone it for as long as possible. However I don't think we are particularly hardwired to prefer this form of weird cryonic rebirth over never waking up at all. Given that our general preference to not die has nothing fundamental about it, but is rather a case of us following our evolutionary leanings, what makes it so obvious that cryonic rebirth is a good thing. Some form of longetivity research which extends our life to say 200 years without going the cryonic route with all the above risks especially for the first few generations of cryonic guinea pigs, seems much harder to argue against.

Reason #7 not to sign up: There is a significant chance that you will suffer information-theoretic death before your brain can be subjected to the preservation process. Your brain could be destroyed by whatever it is that causes you to die (such as a head injury or massive stroke) or you could succumb to age-related dementia before the rest of your body stops functioning.

Reason #5 to not sign up: Because life sucks.

Anyone else here more interested in cloning than cryonics?

Seems 100x more feasible.

I don't understand the big deal with this. Is it just selfishness? You don't care how good the world will be, unless you're there to enjoy it?

There's a much better, simpler reason to reject cryonics: it isn't proven. There might be some good signs and indications, but it's still rather murky in there. That being said, it's rather clear from prior discussion that most people in this forum believe that it will work. I find it slightly absurd, to be honest. You can talk a lot about uncertainties and supporting evidence and burden of proof and so on, but the simple fact remains the same. There is no proof cryonics will work, either right now, 20, or 50 years in the future. I hate to sound so cynical, I don't mean to rain on anyone's parade, but I'm just stating the facts.

Bear in mind they don't just have to prove it will work. They also need to show you can be uploaded, reverse-aged, or whatever else that comes next. (Now awaiting hoards of flabbergasted replies and accusations.)