lsparrish's comments

It's just a bunch of automated drones flying in formation. Trying to calculate their orbits ahead of time in any kind of detail would be a fool's errand, instead we'd just use solar light pressure to steer them as needed (they would be very thin, there's no point to making them thick).

With really thin sails (0.78 g/m^2) they don't even need to orbit, as they can use light pressure to compensate for gravity (what Robert Forward termed a 'statite'). The light they reflect hits other sails on the other side, but this isn't a problem if they are distributed uniformly.

Nobody is making use of this service yet. However, if they were, why would it be ghastly for them to voluntarily trade a small number of days worth of terminal decline for a substantially better quality preservation and thus correspondingly higher chance of revival in the future? To me it sounds like an obvious utilitarian tradeoff, like any reasonable person who was well informed about the situation and averse to dying might choose to make.

I'm not sure why people seem so convinced that MNT is a hard requirement here. To be sure there are some components that require fine micrometer to nanometer level precision, but existing mechanical and/or chemical approaches do work, otherwise we wouldn't have things like computer chips

You can draw fibers, use cantilevers, exploit the wavelength properties of laser light, electromagnetically control the path of ionized materials in a vacuum, use piezoelectric actuators that convert current to angstrom level movements, and so on. Not to mention the many approaches to coating a surface with a very thin layer: vacuum deposition, spin coating, electroplating, etc.

You might find this interesting: http://gravitationalballoon.blogspot.com/2013/03/introductio...

> Aldehydes covalently bond and crosslink the proteins and irreversibly kill all of the fixed cells.

That is the textbook answer, however these bonds are only "irreversible" as a matter of biochemistry. You can actually break any chemical bond by increasing the temperature enough. The problem for our purposes is that this means destroying the structure.

> There is zero hope that this provides a solution to cryopreservation except in the slice it up and look at it under the microscope sense.

The trick to reversing the bond without damaging the structure would be in delivering high enough amounts of energy with high enough precision to have only the intended effects. This may or may not be physically possible. However, to rule out the possibility completely, we would need to consider a wide variety of physical interactions that are well outside the range of biology and wet-solvent chemistry, in addition to the full spectra of potential biomimetic and biological approaches.

This technique is useful for general neuroscience purposes, yes. My point was just that it isn't what is critical to preserve for the sake of cryonics.

> The bag with the remains of the watches gets carefully pocketed and some of the money goes towards ordering a round of drinks for everybody.

I might have misunderstood this bit (in which case, oops). I see way too many people making the assumption that cryonics is somehow primarily profit motivated. Taking money out of the cryonics trust to "buy drinks" would potentially cost the lives of patients, as the organization must remain stable in addition to the revival being achievable to begin with. The incentive is towards long term savings.

> So, how about my watch, asks one of the people that handed over his watch and his money. "Oh, that's the hard part, I haven't really studied that yet, come back in a few 100 years and I might have your watch again. But I'm getting better at smashing watches, that's for sure."

This analogy doesn't make much sense to me. Cryonics is about trying to prevent something that will inevitably be smashed from being smashed as badly. Saying cryonics is about smashing things is like saying seat belts are about cars crashing into each other.

His criticism bad (as ever), since he assumes all information needed for nervous system function is the same as all information needed to replicate a given nervous system. Most of the information needed for function in any system is generic across similar systems. We are only interested in the information that is specific to the individual.

Cool story, bro. Cryonics as it currently exists being profitable is 1) irrelevant to whether it works or not, and 2) a persistent myth.

I should also mention that the wood frog is really more a counterexample of vitrification. It forms ice (which they are adapted to tolerate, unlike us), but the interior or the cells remains a slightly more concentrated liquid. It is nowhere near the concentrations used in cryonics, which are high enough to prevent freezing entirely (50-80%). A wood frog cannot survive any temperature below around -5 C.

It's interesting that the comments by cell biologist Len Ornstein in that thread completely omit any mention of high osmolality vitrification, which is what is practiced in cryonics. I get the impression he is not aware of Fahy's approach at all. It probably is not used in his specialty.

HOV is using extremely high concentrations of solutes to reduce the freezing point (a colligative property). That is the only way to vitrify something big like the brain. At least, until some super material is invented that lets us pull out lots of heat really fast. The trouble is that it is toxic to cells to be exposed for very long. With rabbit kidneys and small slices of brain tissue, the exposure time at warm temperatures can be very brief. So with current cryonics we can only make a morphological argument for information theoretic preservation.

With better materials that enable faster cooling, prevent the toxicity mechanisms of the cryoprotectant, and/or block ice formation non-colligatively (certain polymers do this), it is theoretically possible that we could get to a point where the cells are still viable. In that event, it would be like placing the brain in an "off state". You wouldn't be able to resume it again without a body to implant it in, but that's more likely to be on the 200-year radar than nanorepair, so the chances would be improved quite a bit. Also, I suspect more people would sign up for a process that does not involve "killing" their brain cells.

Um. You also stop poverty and wars. That is also your duty.

Not at all what was said. In fact, the whole criticism you linked to is about structure, and ways in which it is supposedly altered beyond repair. The notion that we are transient electric fields that fade the moment the brainwave goes flat is long discredited.

If you think the pursuit of immortality causes mental breakdowns, can you substantiate this with evidence from psychology journals? If not, this strikes me as unreliable folk wisdom.

There is a lot of possible change that does not involve death. I used to buy your argument, but upon reflection I've decided that it does not automatically follow from simple considerations. We need to be a lot smarter to know the answer for sure. Just as negative temperatures are possible, death-free eternities may also be possible.

Lifespan increase is certainly a stronger possibility than immortality, and is therefore a stronger motive to pursue cryonics. So why is so much space wasted talking about it every time someone suggests cryonics? The thousand year or so extension we could reasonably expect with a good aging cure and decent public safety is pretty significant regardless of eternal considerations.

My gut estimate is that the chance is somewhere in the 1-10% range. I've been thinking about it for around 5 years. Part of why that number is so high is the relative lack of coherent and nuanced counterargument that demonstrates the critic at least understands the issue (not just one aspect, but the whole huge convoluted topic) well. I may end up becoming such a critic myself, eventually, but so far things aren't looking so bad for cryonics.

It is true that chances can't just be "non-zero" and be rational, nor simply based on faith, because that's basically Pascal's Wager. However I think my 1-10% gut feeling is something that I could probably be talked out of if it were really arbitrarily low like people keep assuming.

Assuming that probability range, I think selling to ordinary people is pretty defensible at $50k-$500k rates, because we already spend around $5M to avoid accidental deaths via regulatory tradeoffs. If it is lower (0.1% say) and yet still not arbitrarily low, we would then need to restrict to either very rich or very desperate people (where the ratio of marginal utility of life to marginal utility of a dollar differs significantly from the norm). Arbitrarily low chances literally on level with egyptian mummification or worshipping a random god is definitely not something that should be sold to anyone (except as a novelty maybe).

Note also that cryonics storage cost is influenced by economies of scale, so mass-produced cryonics is likely to be a lot less expensive per person than the cost you see on the market today. If you could seriously measure a non-arbitrary 0.01% it wouldn't necessarily be impossible to justify even on the mass market and even to relatively death-complacent people -- it would just have to be very cheap for them. Granted, gut feelings are hard to calibrate well to reality at such extremes (hence lottery tickets) so I'm not going to seriously argue that, I'm just saying this to give you a feel for why I think there's a need for fairly strong counterargument before you can reasonably take the position that cryonics is just innately bad/fraudulent business.

I also anticipate various positive externalities from the cryonics business, such as sooner (eventual) development of suspended animation of the damage-free variety, which has potential to save a lot of lives and spare a lot of suffering. These too should be accounted for as part of a robust criticism.

Personally, I'm glad to see cryonics being given more attention and discussion. It is a subject not well understood, even among biologists. If you think people undergoing it today are wasting their money (arguable, though I don't concede to it being obvious), there is still something of value to be gained by discussing the specific obstacles it faces, particularly in a technically inclined entrepreneurial crowd like HN. Many of us are younger, and will benefit from technological development that is only in the beginning stages at this point.

By all means, please, show us peer reviewed sources that contradict it.

> Nanobots cannot repair angstrom-scale freeze damages.

Vitrification avoids ice. Nanobots could e.g. remove toxic compounds from extracellular areas and replace them with nontoxic solutions, and deliver yet-to-be-invented drugs that would activate upon thawing.

> Even biocompatible antifreeze proteins found in arctic oceans have a thermal threshold of 269K, which is no where near cryogenic temperature.

The stuff invented by 21st Century Medicine and used to successfully cryopreserve a rabbit kidney is a combination of the ordinary kind of penetrating antifreeze that depresses the freezing point (glycerol, EG, DMSO, and the like) with polymers that inhibit ice nucleation (functionally similar to antifreeze proteins). It has been known for a while that you can vitrify slowly by using high concentrations of the former kind of solute (depress the freezing temperature to below the glass transition temperature and the cooling rate no longer matters) but the latter lets you get away with somewhat more water in the mix, is my understanding.

There's a tradeoff when you cool things, where if you get cold enough it slows toxicity. They don't perfuse with the stuff until the brain is already cooled to near 0 degrees C, and it is ramped in concentration over time to prevent osmotic shock.

> Understanding "biology 101" means understanding that biology is about experiments, everyth is empirical (and will be for quite some time I guess), nothing can be said that "it works" in biology or medicine until you experimentally prove it does.

Part of this isn't really biology (as we know it) though, so I'm not sure that biologists who criticize are seeing the whole picture. Look at it like a cryptographer: Is putting a brain in liquid nitrogen a secure erasure method against all future attacks from a determined opponent with lots of resources? Would you trust your financial data to such a method of data erasure?

> "Nature"/"The universe"/"God" is NOT on our side on this path, so there's no room for optimistic thinking, we can only rely on cold (literally) hard science and math!

I like this sentiment, I wish more cryonics people took it to heart, but at the same time I don't believe that "The Force" is actually against us. There is some reasonable burden of proof on the assertion that the data is is utterly gone and out of reach of all realistic future technology.

> (since you are dead).

IMHO this is the cryo equivalent of an ethnic slur. Cryophobia, if you will. It meets the "you can't change this thing about yourself so we outsiders are going to make fun of you for it, nyah nyah" pattern while being devoid of useful information content. Cryonics proponents do not readily concede the point that patients are technically dead, based on the evidence available.

The legal status (which is a fully independent use of the term "dead" and can be readily conceded with absolutely zero consequence to the technical argument) is something else, but if you are implying that cryonics companies would therefore be within their legal rights to dump their patients, that could just as easily be seen as a problem with the law (i.e. it fails to adequately protect cryonics patients). So it's not clear to me why you would think this is an innate ethical shortcoming of the choice to practice cryonics in the first place.

> companies that are under no obligation to actually do what you paid them to do

It certainly would contradict the purpose, and likely the bylaws, of a cryonics organization to fail to keep patients safe, for at least the period of time that is realistic given the limits of initial funding and uncontrollable factors world economic stability. (100 years is definitely more reasonable than a million.) Assuming the funds set aside experience real growth above the rate of inflation, the risk could actually decline over time because the financial safety net would be larger.

One possible approach if you think the time is going to be long before the needed technology is available, would be to allocate funding towards measures designed to stabilize the economy, avoid war, and/or prevent natural disasters. The other approach would be to try and create disaster-proof cryobunkers (but there's physical limits, as always).