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oge comments on We really need a "cryonics sales pitch" article. - Less Wrong
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CronoDAS, I'm glad you brought up this issue. Sadly, I don't think there's good evidence that cryo, as practiced today, works. I think it is reasonable (but of course, not ideal) for people to dismiss things which are only theoretically possible but not practically possible.
If we had verifiably working cryo today, it might be easier to change people's minds.
Cryonics is being deeply confused with suspended animation in this thread. Cryonics has nothing to do with cellular viability. It's only about preserving the wiring and physical structure of the brain by any means necessary. In current cryonics, all cells are totally and completely dead long before the procedure is finished. But we also have electron micrographs showing very good structural preservation of these dead cells. The cryonics revival technology will need to manipulate trillions of atoms inside of each of billions of cells. No low tech is going to be able to revive them.
Thank you for clarifying this point.
FYI I was referring only to "Cryonics" when I said cryo in the parent comment, not to "suspended animation".
I think your "might" is a severe understatement. If people could actually see other previously dead people walk, this would have an immediate and large effect.
If they could even just revive a mouse, that'd help a lot already.
What is the largest living thing that has been successfully pulled out of cryo? A single cell? Disconnected tissue? An organ?
I'd find a single cell not terribly convincing, a working organ much more so.
(context: I haven't signed up and don't currently intend to, but it's mentally marked as "keep an eye on this, additional information may change my mind.")
Technically, it's the frogs and fish that routinely freeze through the winter. Of course, they evolved to pull off that stunt, so it's less impressive.
We've cryopreserved a whole mouse kidney before, and were able to thaw and use it as a mouse's sole kidney.
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2781097/
We've also shown that nematode memory can survive cryopreservation:
http://www.dailymail.co.uk/sciencetech/article-3107805/Could-brains-stay-forever-young-Memories-survive-cryogenic-preservation-study-shows.html
The trouble is that larger chunks of tissue (like, say, a whole mouse or a human brain) are more prone to thermal cracking at very low temperatures. Until we solve that problem, nobody's coming back short of brain emulation or nanotechnology.
Nitpick: The article talks about a rabbit kidney, not a mouse one
It also isn't entirely clear how cold the kidney got, or how long it was stored. It's evidence in favor of "at death" cryonics, but I'm not sure how strong of evidence it is. Also, it's possible to survive with substantially more kidney damage than you would even want to incur as brain damage.
Waterbears routinely survive freeze-thaw cycles (and much more besides).