Cryonics Information

It can be hard to get factual information about Cryonics and most wiki pages appear as if they were written by Cryonics Enthusiasts or PR men - Below is a comprehensive list of the most factual websites. The main body of text is from:

"Cryonics is the practice of freezing clinically dead people in liquid nitrogen with the hope of future reanimation.

Presently-nonexistent nanotechnology or mind uploading are the favored methods envisioned for revival.

Scientists will admit that some sort of cryogenic preservation and revival does not provably violate known physics. But they stress that, in practical terms, freezing and reviving dead humans is so far off as to hardly be worth taking seriously; present cryonics practices are speculation at best, and quackery and pseudoscience at worst.

Nevertheless, cryonicists will accept considerable amounts of money right now for procedures based only on vague science-fiction-level speculations, with no scientific evidence whatsoever that any of their present actions will help achieve their declared aims. They sincerely consider this an obviously sensible idea that one would have to be stupid not to sign up for.

Cryonics should not be confused with cryobiology (the study of living things and tissues at low temperatures), cryotherapy (the use of cold in medicine) or cryogenics
(subjecting things to cold temperatures in general).

Scientific evidence for efficacy of current practice

There is no scientific evidence whatsoever that any of what cryonicists currently do will make revival any easier, or even that it does preserve the neural information — they just think it sounds like a plausible hypothesis that it will.

There is no scientific evidence that it will be more effective than the preservation technology the ancient Egyptians used on their pharaohs, viz., taking the brain out in pieces via the nose and putting it in a jar next to the mummy for safekeeping — with their knowledge and beliefs at the time suggesting a non-zero probability that this would work. They could just as easily have said, "In 6000 years we'll be able to do anything!" But even the so-called technological singularity won't be enough to get the pharaohs back.

Ben Best, CEO of the Cryonics Institute, supplies in Scientific Justification of Cryonics Practice a list of cryobiology findings that suggest that cryonicists might not be completely wrong; however, this paper (contrary to the promise of its title) also contains a liberal admixture of "then a miracle occurs." His assertions as to what cited papers say also vary considerably from what the cited papers' abstracts state.

Alcor Corporation calls cryonics "a scientific approach to extending human life" and compares it to heart surgery. This is a gross misrepresentation of the state of both the science and technology and verges on both pseudoscience and quackery.


Keeping the head or body at -196°C stops chemistry, but causes massive damage to the cells. The following problems (many of which are acknowledged by cryonicist) would all need to be solved to bring a frozen head or body back to life. Many would need breakthroughs not merely in engineering, but in scientific understanding itself, which we simply cannot predict.

  • Freezing frozen organs recoverably. (We already do this routinely with embryos and there's good work on freezing and recovering organs.)
  • Cloning most of a body from recoverable DNA. (We're closer to this one than any of the others below.)
  • Nanobots. Present nanotechnology has no idea how to get there from here. Computer-controlled nanoscopic miracle workers violate physics. Nanobots won't resemble the popular image of macroscopic industrial robots a millionth of the size with their own built-in supercomputers — they'll be carefully designed chemicals, much like cells or enzymes (the real-life examples of nanobots). Things are different at nanoscale.
    • "Nanobots!" is not the magic answer to everything any more than "really small tweezers!" is. Fixing the damage would have to be physically possible — which it may not be — and humans would still need to know how to actually fix whatever it was in order to program the nanobots.
  • Fixing the freezing damage to the original frozen brain. The dendrites (10,000 connections for each of the 100 billion neurons — that's 1015 dendrites to check) are cracked badly by the freezing process — "acoustic fracturing events," like when you drop an ice cube into a drink. What is the process for fixing a frozen brain that's cracked into several, or hundreds of, pieces, with dendrites shattered at a microscopic level? This is a problem even with vitrification.
    • The damage may not be mappable, let alone repairable. Damaging energies are required to scan at 5 nm resolutions, where things start going quantum
  • Reattaching a severed head or transplanting the brain.
    • Alternately: reading the patterns from the original brain and writing those to the cloned brain (uploading and downloading minds). Cryonicists speak of mind-uploading as if it's a mere technical detail that's just around the corner, rather than something we don't even know can meaningfully be discussed.
  • The cryopreservatives, that prevent ice crystal damage, are themselves toxic and would need to be removed from the tissues. (This is really a pretty minor problem compared to everything else listed herein.)
  • Preserve neurons at ~100% viability. 99% won't cut it. As those who work with stroke victims (1.2 billion neurons, or about 1%, lost in a severe stroke know, large chunks of personality and memory can go out the window and the sufferer is frequently quite disabled afterwards. Stroke victims are presently considered to be the same person afterward (occupying the same body and all that), but cryonics needs to preserve pretty much the entire person if it is to live up to its promise. 0.03% loss would be consistent with the neuron loss from aging one year.
  • Once you've fixed the body cells and the brain paths, you have a recovered corpse. Your next task is to resurrect the dead.
  • The two existing cryonics facilities are charities with large operational expenses run by obsessive enthusiasts. They are small and financially shaky. In 1979, the Chatsworth facility (Cryonics Company of California, run by Robert Nelson) ran out of money and the frozen bodies thawed. The cryonics movement as a whole was outraged and facility operators are much more careful these days. But it's an expensive business to operate as a charity.

  • Of the early frozen corpses, only James Bedford remains, due to tremendous effort on the part of his surviving relatives. Though they didn't do anything to alleviate ice crystals, so his remains are likely just broken cell mush by now.

  • William T. Jarvis, president of the National Council Of Health Fraud said, "Cryonics might be a suitable subject for scientific research, but marketing an unproven method to the public is quackery."

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