Within the immortalist community, cryonics is the most pessimistic possible position. Consider the following superoptimistic alternative scenarios:

  1. Uploading will be possible before I die.
  2. Aging will be cured before I die.
  3. They will be able to reanimate a whole mouse before I die, then I'll sign up.
  4. I could get frozen in a freezer when I die, and they will eventually figure out how to reanimate me.
  5. I could pickle my brain when I die, and they will eventually figure out how to reanimate me.
  6. Friendly AI will cure aging and/or let me be uploaded before I die.

Cryonics -- perfusion and vitrification at LN2 temperatures under the best conditions possible -- is by far less optimistic than any of these. Of all the possible scenarios where you end up immortal, cryonics is the least optimistic. Cryonics can work even if there is no singularity or reversal tech for thousands of years into the future. It can work under the conditions of the slowest technological growth imaginable. All it assumes is that the organization (or its descendants) can survive long enough, technology doesn't go backwards (on average), and that cryopreservation of a technically sufficient nature can predate reanimation tech.

It doesn't even require the assumption that today's best possible vitrifications are good enough. See, it's entirely plausible that it's 100 years from now when they start being good enough, and 500 years later when they figure out how to reverse them. Perhaps today's population is doomed because of this. We don't know. But the fact that we don't know what exact point is good enough is sufficient to make this a worthwhile endeavor at as early of a point as possible. It doesn't require optimism -- it simply requires deliberate, rational action. The fact is that we are late for the party. In retrospect, we should have started preserving brains hundreds of years ago. Benjamin Franklin should have gone ahead and had himself immersed in alcohol.

There's a difference between having a fear and being immobilized by it. If you have a fear that cryonics won't work -- good for you! That's a perfectly rational fear. But if that fear immobilizes you and discourages you from taking action, you've lost the game. Worse than lost, you never played.

This is something of a response to Charles Platt's recent article on Cryoptimism: Part 1 Part 2

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I like this post. Upvoted.

On a tangiential node, I had an experience today that made me take cryonics much more seriously. I had a (silly, in retrospect) near-miss with serious injury, and I realized that I was afraid. Ridiculously, helplessly, calling-on-imaginary-God-for-mercy afraid. I had vastly underestimated how much I cared about my own physical safety, and how helpless I become when it's threatened. I feel much less cavalier about my own body now.

So, you know, freezing myself looks more appealing now that I know that I'm scared. I can see why I'd want to have somewhere to wake up to, if I died.

Your comment suggests a convenient hack for aspiring rationalists to overcome their fear of cryonics.

I wonder if cryonicists (before signing up) are more likely than cryocrastinators to have experienced an "oh jeez I almost died" moment. Anecdotal evidence: I'm signed up and someone once tried to rob me at gunpoint. It would also be interesting to know how many close friends or relatives of cryonicists have died compared to cryocrastinators.
Anecdotal evidence: although sympathetic to the idea, I am not signed up, and have had two close brushes with death (that I know of).
Not in my case for the original plan. I decided to sign up for cryonic suspension some day at age 14 (1974), after reading Robert Ettinger's Man Into Superman (an underappreciated book, in my opinion). I followed through in 1990 with Alcor. This November 2 (coincidentally my 51st birthday) marks the 20th anniversary of my suspension membership. I did have an health issue recently which has motivated me to get more involved in trying to untangle the cryonics clusterfuck (long story). I had a branch retinal vein occlusion in my right eye back in June (basically a stroke in that retina), which has caused some vision loss. Since then I've lost about 40 lbs. and I take Lisinopril to lower my blood pressure (116/80 this morning).
Datapoint: I didn't have such an experience before deciding to sign up.
I've had a fair number of relatives die. This is actually one reason I'm delaying on cryonics right now. I first got strongly interested in cryonics about 6 months ago. Then shortly after that, multiple relatives of fairly young ages died fairly suddenly. They weren't the first such deaths in my family by any means. And a family friend died at about the same time from cancer that he had had for a very long time. The initial reaction was that I should run off and sign up for cryonics right now. So I'm now delaying in part to make sure that I am making the decision more rationally and not just based on sudden recent events clouding my judgment. That and the whole thing with cryonics being fairly expensive for a grad student budget are the main causes of not signing up at this point.
I've been scared shitless all my life but it gradually gets better. I stopped caring that much and am much happier now. I'm at the point where I'm really too lazy to go for Cryonics now. Although note that I never doubted that Cryonics could work or that it is worth it if you care. But really the more I learn the less I fear not being around. Of course I do want to be around, I don't want to die. But I'm just not going wear a helmet while driving a car, if you see what I mean. I learnt that there are so many possibilities, MWI, the Mathematical Universe etc. and most of all you people. If I'm not around then someone like you or EY will be who pretty much contain all awesomeness I could ever mobilize. I know many people wouldn't even be satisfied by having a perfect copy around, because it's not them. I'm pretty much the other extreme who's already satisfied with having people around who I believe are at least as worthy as I am so to not fear death anymore. Further there are the possibilities that the future will suck anyway :-)
It actually didn't occur to me to wear a helmet in a car. For me this was sort of the dividing line between "I'm young, I'll live forever" and "Wait, shit, I won't, I really do need to do all those boring things like use hand sanitizer and look both ways before crossing the street and take my vitamins."
Wait, should I wear a helmet in my car? :) It sounds plausible. I'd say no, because of reduced visibility increasing odds of accident, and already ample protection from airbags, seatbelt, and crumple-zone into rigid structure protecting against crushing.
A good motorcycle helmet provides well over 180 degrees of side vision, while your peripheral vision can only reach about 160 degrees. While I can't find a reference, IIRC the percentage of motorcycling fatalities resulting from head injuries is around 50%, and the percentage of car fatalities resulting from head injuries is considerably higher. So, disregarding the vastly diminished prior probability of all-cause fatalities in a car, you should actually be more adamantly in favor of helmet use in a car than on a motorcycle.
Why would we disregard that?
I'd rather wear a helmet than signing up for cryonics. But most people who sign up for cryonics probably do not wear helmets.

Since you mentioned Benjamin Franklin, apparently when he died he left two trust funds to demonstrate the power of compound interest over a couple of centuries. The example of these trusts shows that the idea of a reanimation trust staying intact for centuries doesn't sound absurd:



You forgot the most optimistic of all:

  1. I could do absolutely nothing, get cremated and the eventual Friendly AI will still be able to reanimate me, via time-travel or equivalent.
Before I saw your comment I made the same one. Now I deleted mine and I'll upvote yours.
Well, she forgot beta-level simulations too. The AI resurrecting you by interpreting recorded behavioral patterns and your DNA.
Is this a standard term? I've only seen it in Alastair Reynolds's writing.
Me too, but I think resurrection without a backup should be seriously considered given the possibility of superhuman AI. That is, a simulation based on modelling the behavioural patterns of the person copied, attempting to predict their reactions to a given stimulus. If there are enough records of the person and by the person plus their DNA, given sufficiently powerful AI, such a beta-level simulation might be sufficiently close so that only a powerful posthuman being could notice any difference compared to the original. I'm not sure if Reynolds was the first person to consider this, I doubt it, but I deem the term beta level simulation adequate.
I think this should be considered conceivable, but not in the same realm of plausibility as cryonics working. If you rate cryonics chances of working low, this is much lower. If you rate its chances extremely high, this possibility might be in a more moderate range. My favorite idea is to scan interstellar dust for reflected electromagnetic and gravitational data. Intuitively, I imagine this would lead first to resolving only massive objects like stars and planets, but with time and enough computation it could be refined into higher details.
This is also the approach they take on the TV show Caprica.
It was my understanding that this is one of Kurzweil's eventual goals: reconstructing his father from DNA, memories of people who knew him, and just general human stuff.
As we move farther away it becomes harder to self-identify. I have some difficulty self-identifying with an upload but there's still a fair bit. I have a lot of trouble identifying with a beta copy. In fact, I imagine that an accurate beta version of me would spend a lot of time simply worrying about whether it is me. (Of course now putting that in writing means that out super friendly AI will likely only make a beta of me that does do that worrying is potentially counterproductive. There's a weird issue here where the more the beta is like me the more it will worry about this. So a beta that was just like me but didn't worry would certainly not be close enough in behavior for me to self-identify with it. So such worrying in a beta is evidence that I should make the self-identification with that beta.)
You will get over it fast. Ever experienced a few hours of memory loss of found some old writing of yours that you can not recall? The person you are changes all the time. You will be happy to be there, and probably find lots of writing about how/why an upload you enough by other minds.
Yes. And this bothers me a bit. Sometimes I even worry (a teeny tiny bit) that I've somehow switched into a parallel universe where I've wrote slightly different things (or in some cases really dumb things). When I was younger I sometimes had borderline panic attacks about how if I didn't remember some event how could I identify as that individual? I suspect that I'm a little less psychologically balanced about these sorts of issues than most people...
Most people maybe, but not most LWers I bet. I have had such attacks too...
I am deeply frightened by the fact that most important developments in my live are accidents. But well, there is little use in being afraid. You could try to figure out how much you actually change from time unit to time unit by journaling, or by tracking mental changes. Maybe you also find a technique that can be adapted to measure your discomfort and to try out ways to reduce it. I externalize some of my brainpower into note-files, with some funny results.
One way to resolve the dissonance this produces is to quit identifying with yourself from one point in time to the next. Me-from-yesterday can be seen as a different self (though sharing most identity characteristics like values, goals, memories, etc.) from me-from-today.
I dislike this concept, but that is what with. Identity breaks down, and personhood ends.
That's an interesting way of thinking about it. My take on it is the opposite. If an accurate copy of me was made after my death, I am pretty sure the copy wouldn't care if it was me or not, just as I don't care if I am as my past self wished me to be. If the copy was convinced it was me, there would be no problem. If it was convinced it wasn't, than it wouldn't think of my death as any more important than the deaths of everyone else throughout history.

Within the immortalist community, cryonics is the most pessimistic possible position.

Indeed; I think the cryonics organizations themselves have a saying, "Cryonics is the second worst thing that can happen to you."

Cryonics can work even if there is no singularity or reversal tech for thousands of years into the future.

This doesn't alter your overall point much but this seems unlikely. Aside from the issue of the high probability of something going drastically wrong after more than a few centuries, low-level background radiation as well as intermittent chemical reactions will gradually create trouble. Unfortunately, estimating the timespan for when these will be an issue seems difficult but the general level seems to be somewhere between about 100 to a 1000 years... (read more)

8Paul Crowley
How Cold is Cold Enough? estimates that 1 second at body temperature is equivalent to 24.628 million years at LN2 temperatures, as far as chemical reactions are concerned. The speed of nuclear processes isn't changed of course.
Hmm, that's a much tighter estimate. (The page is poorly written (and frankly comes across as condescending(telling people that "exp" is some mathematical operation is not helpful) and poorly formatted. This is not good when cryonics already triggers some peoples' crank warning detectors) The math seems correct. That gives a much better bound for when chemical reactions will be an issue. It seems strongly then that my initial estimate that chemical reactions prevent kiloyear preservation is pretty wrong.
Isn't that a trivial engineering detail to be solved by liquid helium and lots of radiation shielding?
Well, no. You can't put a body at liquid helium temperatures without massive damage (the whole vitrification trick doesn't work as well). And liquid helium is also much harder to get and work with than liquid nitrogen. Helium is in general much rarer. The radiation shielding also will only help with background radiation. It won't help much with radiation due to C-14 decay or due to potassium decay. Since both are in your body naturally there's not much to do about them.
I don't know so much about C-14, but wouldn't potassium decay's effects be small on timescales ~10,000 years? The radioactive natural isotope K-40 has a ridiculously long half life (1.25 billion years, which is why potassium-argon dating is popular for dating really old things) and only composes 0.012% of natural potassium. Potassium's also much less abundant in the body than carbon - only about 140g of a 70kg person is potassium, although admittedly it might be more concentrated in the brain, which is the important part. ETA - I did calculations, and maybe there is a problem. Suppose 0.012% of K is K-40 by mass. Then I get 0.0168 grams of K-40 in a body, which comes out as 0.00042 moles, 2.53e20 K-40 atoms. With a 1.25 billion year half life that makes 1.40e15 decays after 10,000 years. In absolute terms that's a lot of emitted electrons and positrons. I don't know whether the absolute number (huge) or the relative number (miniscule) is more important though.
I don't have enough background to estimate how serious the decay would be. But with 1.40e15 decays after 10,000 years that's around 3000 decay events a second (in practice most of that will be in the first few thousand years given that decay occurs exponentially). It seems that part of the issue also is that there's no repair mechanism. When something is living it can take a fair bit of radiation with minimal negative results. In some circumstances living creatures can even benefit from low levels of radiation. But radiation is going to be much more damaging to cells when they can't engage in any repairs. Edit:Also note that the majority of the radiation that people are subject to is from potassium 40 so if this is ok then we're generally ok. It seems that radiation is not a major limiting factor on long-term cryonic storage.
It's true that radiation is more damaging to cells when they can't engage in repairs. But damage is nothing to worry about in this case. When e.g. a gamma ray photon breaks a protein molecule, that molecule is rendered nonfunctional; enough such events will kill a cell. But in the context of cryonics, a broken molecule is as good as an intact one provided it's still recognizable. Rendering it impossible to tell what the original molecule was, would take far more thorough destruction. From Wikipedia, "The worldwide average background dose for a human being is about 2.4 millisievert (mSv) per year." Even a lethal prompt dose is a couple of thousand times this quantity. And you can take maybe 10 times the lethal dose and still be conscious for a little while. So that's 20,000 years of background radiation verified to not even significantly damage, let alone erase, the information in the brain. I'd be surprised if the timescale to information theoretic death by that mechanism was very much less than a billion years.
The lack of an automatic repair mechanism makes things hairier, but while frozen, the radiation damage will be localized to the cells that get hit by radiation. By the time you get the tech to revive people from cryonic freezing, you'll most likely have the tech to fix/remove/replace the individual damaged cells before reviving someone. I think you're right that radiation won't be a big limiting factor, though it may be an annoying obstacle.
Ok, not so trivial. The isotope breakdown issue might be unsolvable (unless you have nanobots to go in and scrub out the unstable isotopes with?) but I would imagine that to be quite a bit less than you get from solar incidence. Liquid helium cooling doesn't seem like it would cause information-theoretic damage, just additional cracking. Ice crystal formation is already taken care of at this point. But liquid helium level preservation tech really does not seem likely to be needed, given how stable LN2 already gets you. The only reason to need it is if technological progression starts taking a really long time.
If you've got good enough nanobots to remove unstable isotopes you almost certainly have the tech to do full out repair. I don't know if the radiation less than what you get from solar incidence. I suspect that it is but I also suspect that in a general underground environment much more radiation will be due to one's own body than the sun. Cracking can include information theoretic damage if it mangles up the interface at synapses badly enough. We don't actually have a good enough understanding of how the brain stores information to really make more than very rough estimates. And cracking is also a problem for the cryonics proponents who don't self-identify with a computerized instantiation of their brain.

Good post, upvoted.

I think that your remark

But the fact that we don't know what exact point is good enough is sufficient to make this a worthwhile endeavor at as early of a point as possible. It doesn't require optimism -- it simply requires deliberate, rational action.

assumes a utility function which may not be universal. In particular, at present I feel that the value of my personal survival into transhuman times is dwarfed by other considerations. But certainly your points are good ones for people who place high value on personally living into transhuman times to bear in mind.

Indeed, I always feel there is too much ought on LW. After all rationality is about winning and if I don't care that much about my personal survival then Cryonics is a waste of money.

Although it's not marked as the inspiration, this post comes straight after an article by many-decades cryonicist Charles Platt, which he wrote for Cryonics magazine but which was rejected by the Alcor board:

Cryoptimism Part 1 Part 2

Platt discusses what he sees as the dangerously excessive optimism of cryonics, particularly with regard to financial arrangements: that because money shouldn't be a problem, people behave as though it therefore isn't a problem. When it appears clear that it is. To quote:

In fact their determination to achieve and defend their

... (read more)
Correct. I will add the links in the article.
1Paul Crowley
Hey David, welcome to Less Wrong, and thanks for the link to these articles!
Count yourself as having other-optimised ;-p
0Paul Crowley
Marvellous :-) Does that mean you've started looking at the Sequences?
Glanced over them. I started with the Intuitive Explanation and my brain slid off it repeatedly. I fear that if that's the "intuitive" explanation, then all the merely quite bright people are b*ggered. Needs rewriting for the merely quite bright, as opposed to the brilliant. This is what I meant about how, if you have a pitch, it better target the merely quite bright if you have any serious interest in spreading your favoured ideas. This ties into my current interest, books that eat people's brains. I'm increasingly suspecting this has little to do with the book itself. I realise that sentence is condensed to all but incomprehensibility, but the eventual heartbreaking work of staggering genius will show a lot more of the working.
Writing accessible math stuff is pretty hard, since sometime after you've figured out the basic math, you start getting blind to what was difficult in the first place. I suppose you'd need a continuous supply of math-naive test readers who you could A-B test continuing iterations of the text with, trying to come up with one that presents the easiest path to actually making the content comprehensible. I'm having trouble coming up with any articles that try to present some abstract mathematical concept in anything resembling the form actual mathematicians work with, and wouldn't be pretty tough to work through with no preknowledge of learning and working with abstract math concepts. Maybe it's just hard to do. On a quick glance, the intuitive explanation article seems several times longer than people who would want to get a quick idea about what all the Bayes stuff is about would be prepared to read. I'm guessing this refers to books that start cults, not just books that will consume limitless amount of brainpower if you let them? In any case, quite interested in hearing more about this.
That's another factor. But I just couldn't get a feel for the numbers in the breast cancer example. This is noting that I found Bruce Schneier's analogous numbers on why security theatre is actively damaging [couldn't find the link, sorry] quite comprehensible. (I certainly used to know maths. Did the Olympiad at high school. Always hated learning maths despite being able to, though, finally beaching about halfway through second-year engineering maths twenty years ago. I recently realised I've almost completely forgotten calculus. Obviously spent too long on word-oriented artistic pursuits. I suppose it's back to the music industry for me.) As someone who is definitely smart but has adopted a so far highly productive life strategy of associating with people who make me feel stupid by comparison, I am happy to be a test stupid person for these purposes. More a reference to how to cure a raging memetic cold. Cults count (I am/was an expert on Scientology ), Ayn Rand sure counts (this being the example that suggests a memetic cold is not curable from the outside and you have to let the disease run its course). What struck me was that quite innocuous works that I don't get a cold from have clearly caused one in others. "Memetic cold": an inadequate piece of jargon I made up to describe the phenomenon of someone who gets a big idea that eats their life. As opposed to the situation where someone has a clear idea but is struggling to put it into words, I'm not even entirely sure I'm talking about an actual phenomenon. Hence the vagueness. Possible alternate term: "sucker shoot" (Florence Littauer, who has much useful material but many of whose works should carry a "memetic hazard" warning sign). It's full of apparent life and vitality, but sucks the energy out of the entire rest of your life. When you get an exciting new idea and you wake up a year later and you've been evicted and your boyfriend/girlfriend moved out and your friends look at you like you're crazy beca
Another thing re. the Bayesian explanation. It's probably quite a bad place to start reading LW content. It seems to really aim to get the reader to be able to do the math instead of just presenting the general idea. I find the newer sequence stuff a lot more approachable. Haven't ever bothered to go through the Bayes article myself. The memetic cold thing is interesting, in particular, like you said, because there isn't a foolproof way of telling if the all-consuming weird preoccupation is fundamentally flawed, on the right track but most likely going to fail, or going to produce something genuinely useful. Recognizing mathematics in general as something other than a memetic cold before mathematics established itself as something useful might not have been entirely easy, and there's still the tension between math obsession that gets you the Fields medal, math obsession that makes you write angry handwritten letters about your disproof of Cantor's diagonalization argument for decades, and math obsession that makes you correlate numerological sums of the names of Fortune 500 CEOs with charts made from the pages of the Hebrew Bible to discover the identity of the Antichrist. This also reminds me a bit of Robert Pirsig, both in the Motorcycle book and in Lila. Pirsig talks about the difficulty of discerning good stuff from bad stuff when the stuff goes outside a preset framework to evaluate it in, describes his personal sucker shoot episodes, and the books have probably started more than a few memetic colds themselves.
You can get a bad memetic cold by deliberately compromising your memetic immune system: decompartmentalising too aggressively, getting a not quite so magical click and it all becomes terribly clear: the infidel must die! That's an extreme failure mode of decompartmentalisation, of course. (Some lesser ones are on RationalWiki: Engineers and woo.) But when you see a new idea and you feel your eyes light up with the realisation that it's compelling and brilliant, that’s precisely the time to put it in a sandbox. Maybe. I'm not sure yet. It feels a bit like deliberate stupidity. On the other hand, we live in a world where the most virulent possible memes are used to sell toothpaste. Western civilisation has largely solved food and shelter for its residents, so using infectious waste as a token of social bonding appears to be what we do with the rest of our lives.
0Paul Crowley
My video lecture you've found also includes a brief introduction to Bayes' Theorem.
If interpreted in that way, it fails completely. It doesn't respond in any way to Pratt's argument that the cryonics industry does not have the financial resources to deliver on its promises, and that the shortfall gets larger as more people sign up. Isparrish simply advises people to ignore this and to optimistically sign up anyways. Since Isparrish does not seem to be irrational, I have to assume he is not attempting to respond to Platt. Edit: Whoops. Bad assumption.
I should clarify that it was not his main point about shortfalls due to signups, but the peripheral point about cryonics being optimistic that I was replying to. I disagree with his main point to a limited degree, i.e. I consider it probable that Alcor is not going to go bankrupt, though I recognize the need to be alert to the possibility. As he said, money has shown up in the past from wealthy donors who don't want it to fail. I'm not upset at the inequity there because the donors are purchasing social status, and I don't have a problem with paying slightly more (or, if I can afford it, a lot more) to help cover someone else's expenses. (I am more open to socialistic logic than most current cryonicists.)

After reading Eliezer on it, I with certainty to sign up for cryonics, but I figured I'd wait until I had a more stable lifestyle. I'm currently traveling through Asia - Saigon, Vietnam right now, Kuala Lumpur, Malaysia next. I figure if the lights go off while I'm here, it's not particularly likely I'd make it to a cryonics facility in reasonable time.

Also, it's the kind of thing I'd like to research a bit, but I know that's a common procrastination technique so I'm not putting too much weight on that.

Nice post, though it avoided the reason why I don't intend to get cryopreserved. That is, because it's way too expensive.

I think cryonics is a waste of money unless you want to make living copies of a dead person or otherwise have a reason to preserve information about the dead. Cryonics does not prevent the death of you, it just prevents the destruction of the leftovers as well.

You come off as assuming that the people in this thread are not aware of the personal identity debate. That doesn't really strike me as productive. David Chalmers did go into this in his Singularity analysis paper. In chapter 10, he basically noted that both the standard stances lead into unintuitive results in scenarios that seem physically possible. The interesting thing about the personal identity discontinuity stance is to imagine growing up in a world where reviving people from something that very obviously halts all their bodily functions for a nontrivial duration, such as cryonics or uploading, is commonplace. All your life you see people getting killed, have their heads vitrified, and then the mind-states get reinstated in new bodies and these new people are in all appearances the same as the ones that died. How would people develop the intuition that the metabolic cessation leads to personal death, and the revived people are new individuals with false memories, in this world?
I know the debate exists, I just think the wrong side is winning (in this little corner of the Internet). These discussions usually occur in an atmosphere where there is far more presumption than there is knowledge, regarding the relationship between the physical brain and elements of personhood like mind, consciousness, or identity. The default attitude is that a neuron is just a sort of self-healing transistor, that the physical-computational reality in the brain that is relevant for the existence of a person is a set of trillions of physically distinct but causally connected elementary acts of information processing, that the person exists in or alongside these events in some vague way that is not completely specified or understood, and that so long as the cloud of information processing continues in a vaguely similar way, or so long as it is instantiated in a way with vaguely similar causality, the person will continue to exist or will exist again, thanks to the vague and not-understood principle of association that links physical computation and self. The view of the self which naturally arises subjectively is that it is real and that it persists in time. But because of the computational atomism present in the default attitude (described in the previous paragraph), and also because of MWI dogma and various thought-experiments involving computer programs, the dominant tendency is to say, the natural view is naive and wrong, there's no continuity, you are as much your copies and your duplicates elsewhere in the multiverse as you are this-you, and so on ad infinitum, in a large number of permutations on the theme that you aren't what you think you are or what you appear to be. Another reason that people are willing to sacrifice the natural view wholesale has to do with attachment to the clarity that comes from mathematical, physical, and computational concepts. These concepts also have an empirical side to their attraction, in that science has validated their
Thank you for the thoughtful reply. I see the problem with overly cavalier attitudes to personal identity as a reproducible pattern, but I'm not quite willing to let the continuous process view out of the hook that easily either. It seems awfully convenient that your posited process of personal identity survives exactly those events, blinking ones eyes, epileptic fits, sleep, coma, which are not assumed to disrupt personal identity in everyday thought. Unless we have some actual neuroscience to point to, all I know is that I'm conscious right now. I don't see why I should assume that whatever process creates my conscious feeling of self is tied exactly to the layer of physical metabolism. It could be dissolved and created anew several times a second, or it could vanish whenever I lose consciousness. I (or the new me) would be none the wiser, since the consciousness going away or coming into being doesn't feel like anything by itself. Assuming that the continuity of a physical system is indeed vital, it could be that it's tied to cellular metabolism in exactly the convenient way, but I'm not buying an argument that seems to basically come down to an appeal to common sense. This is also why I'm a bit wary of your answer to the thought experiment. I'm not entirely sure how the process of discovery you describe would happen. Suppose that people today do neuroscience, and identify properties that seem to always be present in the brains of awake, alert and therefore supposedly conscious people. These properties vanish when the people lose consciousness. Most likely scientists would not conclude that the dissolution of this state intrinsically tied to consciousness means that the subject's personal identity is gone, since common-sense reason assures us that we retain our personal identity through unconsciousness. I don't see any way of actually knowing this though. Going to sleep and waking up would feel exactly the same for the sleep-goer and up-waker if the unconscious
The philosophical habit of skeptically deconstructing basic appearances seems to prepare people badly for the task of scientifically understanding consciousness. When considering the relationship between mind and matter, it's a little peculiar to immediately jump to complicated possibilities ("whatever process creates my conscious feeling of self ... could be dissolved and created anew several times a second") or to the possibility that appearances are radically misleading (consciousness might be constantly "going away or coming into being" without any impact on the apparent continuity of experience or of personal existence). Just because there might be an elephant around the next corner doesn't mean we should attach much significance to the possibility. It is unlikely that society would develop the capacity for mind uploading and cryonic resurrection without also coming to understand, very thoroughly, how the brain works. We may think we can imagine these procedures being performed locally in the brain, with the global result being achieved by brute force, without a systemic understanding. But to upload or reanimate you do have to know how to put the pieces back together, and the ability to perform local reassembly of parts correctly, in a physical or computational sense, also implies some ability to perform local reassembly conceptually. In fact it would be reasonable to argue that without a systemic understanding, attempts at uploading and cryonic restoration would be a game of trial and error, producing biased copies which deviate from their originals in unpredictable ways. Suppose you use high-resolution fMRI time series to develop state-machine simulations of microscopic volumes in the brain of your subject (each such "voxel" consisting of a few hundred neighboring neurons). You will be developing a causal model of the parts of the subject's brain by analysing the time series. It's easy to imagine the analysis assuming that interactions only occur between ne
It wasn't philosophers who came up with general relativity and quantum mechanics when everyday intuition about nature didn't quite add up in some obscure corner cases. Coming up with a simple model that seems to resolve contradictions even if it doesn't quite fit everyday intuition seems to be useful in gaining a better understanding of things. I'm also having genuine difficulties going anywhere past the everyday intuition with the idea of the discontinuity of personal identity separate from the discontinuity of mindstate. The idea of there being only a sequence of conscious moments instead of an intrinsic continuity doesn't present any immediately obvious contradiction and doesn't have the confusion of exactly what the mindstate-independent component of continuous personal is really supposed to be. Of course going with the mindstate history view, now the difference becomes the sliding scale of possible differences from the previous state. It looks like personal continuity would become a matter of degree rather than a binary thing, which pushes things further into the unintuitive. I'm afraid I don't understand what that means. Can you give more concrete examples of physical things that do or don't have this property?
It contradicts the experience of time passing - the experience of change. The passage of time is an appearance, and an appearance is something stronger than an intuition. An intuition is a sort of guess about the truth, and may or may not be true, but one normally supposes that appearances definitely exist, at least as appearances. The object implied by a hallucination may not exist, but the hallucination itself does exist. It is always a very radical move to assert that an alleged appearance does not exist even on the plane of appearance. When you deny the existence of a subject which persists in time and which experiences time during that persistent existence, you are right on the edge of denying a fundamental appearance, or perhaps over the edge already. Normally one supposes that there is an elemental experience of time flowing, and that this experience itself exists in time and somehow endures through time. When you disintegrate temporal experience into a set of distinct momentary experiences not actually joined by temporal flow, the most you can do to retain the appearance of flow is to say that each momentary experience has an illusion of flow. Nothing is ever actually happening in consciousness, but it always looks like it is. Consciousness in every moment is a static thing, but it always has an illusion of change embedded in it. (I suppose you could have a wacky theory of dynamic momentary experiences, whereby they're all still distinct, but they do come into and then go out of existence, and the momentary appearance of flow is somehow derived from this; the illusion would then be the illusion of persistent flow.) To sum up, it's hard to have an actual experience of persistent flow without actually persisting. If you deny that, then either the experience of persistence or the experience of flow has to be called an illusion. And if one becomes willing to assert the persistence of the perceiver, the one having the experience, then there's no particular reas
I'm curious: do you consider sleeping, or falling unconscious after hitting your head, to be as deadly as cryonics?
No. See this discussion, including the spinoff discussion with a now-invisible Roko.
Beautifully put. Thank you.
I go to sleep every night. It doesn't halt my bodily processes, but I become less intelligent then animals. People largely don't seem concerned with animals dying, so the logical conclusion is that someone reduced to such low intelligence is effectively already dead.
This argument is weird, because it implies that you are 100% willing to consider clinical death as 100% dead with no chance of being wrong. What gives you such incredible confidence in your ability to judge the situation correctly at this early stage in the game?
This isn't confidence in present-day criteria of clinical death, it's confidence that completely freezing your brain breaks whatever form of continuity is responsible for persistence of personhood through ordinary life changes. I'm not 100% sure about it, but that is a radically pulverizing transformation compared to just about anything that a brain can live through. Making a new brain in the image of the old brain and from the pieces of the old brain doesn't change that.
First off, if you can't be very nearly 100% sure of failure, you should do cryonics anyway -- as long as your expected value of survival is greater than cost times probability. If you are still only 99% sure cryonics would fail, you should still be willing to bet up to $50,000 on it if your life is worth $5 million. Second off, your argument seems to include damage and suspension under the same umbrella. Suspension as a problem for personhood doesn't make much sense, unless you are willing to admit to there being a real a risk that people who undergo extreme hypothermia also actually reanimate as a different person. Third, repair scenarios as a risk to personhood make sense only if you apply the same criteria to stroke, dementia, and trauma victims who would benefit from similar extreme advances in brain repair technology.
Please be more clear. Are you attacking cryonics based on the amount of brain damage, or the fact that the brain undergoes suspended animation?
So you don't consider a restored body the same as you? I can see why one might not self-identify with a physical copy but most cryonists plan on having their current body restored. Do you not identify with such an entity?
I identify with some forms of restoration but not others. If I cut off all my hair and then it grows back, I have been "restored" without having ever gone away. If I get vaporized now, and then a trillion years later I happen to live again as a Boltzmann brain, that's clearly a copy. There are many conceivable transformations between those two extremes, and as I said to Risto in my first reply, I believe I am something, and that consequently there is an objective fact as to whether a particular transformation just changes me, or whether it actually destroys me (though a substitute may later be created). I think cryonics (and uploading) fall into this latter category. It's not certain but it's likely.

What about - The SAI can reborn me no matter how long I will be dead and how poor my remains will be then?