Yes, cryonics is a much more complex subject than many people give it credit for and many aspects get confused. Whenever someone mentions the brain’s electrical activity being switched off as a sign of irreversible death I think they must be a newbie to the topic. Hypothermia patients frequently lose electrical activity and recover just fine. Structure is the key.
There is in reality a spectrum of cryonics. On the “soft” side would be a future invention (e.g. a very nontoxic cryoprotectant, or a means of rapid perfusion that lets you lower temperatures quickly enough) that permits zero chemical and structural damage, much like is currently only achievable in thin slices. On the “hard” side there are sub-ideal vitrifications and hard freezes.
There’s a spectrum of probabilities of success. Zero damage would be about 100% likely to succeed, whereas hard freeze is probably less than 1%. (Perhaps the chance is higher than that, but the person would be almost completely amnesiac—like a clone but with macroscopic features of the brain preserved.) Ideal conditions achievable today have a significantly higher probability (or percentage of memories preserved) than hard freezing. Unfortunately the unpopularity of cryonics means there’s hardly any infrastructure for it, which means an ideal case is relatively unlikely to actually occur.
Right. I was assuming essentially no damage between death and preservation. Current practice is far from this ideal, as I understand it.
Yes, cryonics is a much more complex subject than many people give it credit for and many aspects get confused. Whenever someone mentions the brain’s electrical activity being switched off as a sign of irreversible death I think they must be a newbie to the topic. Hypothermia patients frequently lose electrical activity and recover just fine. Structure is the key.
There is in reality a spectrum of cryonics. On the “soft” side would be a future invention (e.g. a very nontoxic cryoprotectant, or a means of rapid perfusion that lets you lower temperatures quickly enough) that permits zero chemical and structural damage, much like is currently only achievable in thin slices. On the “hard” side there are sub-ideal vitrifications and hard freezes.
There’s a spectrum of probabilities of success. Zero damage would be about 100% likely to succeed, whereas hard freeze is probably less than 1%. (Perhaps the chance is higher than that, but the person would be almost completely amnesiac—like a clone but with macroscopic features of the brain preserved.) Ideal conditions achievable today have a significantly higher probability (or percentage of memories preserved) than hard freezing. Unfortunately the unpopularity of cryonics means there’s hardly any infrastructure for it, which means an ideal case is relatively unlikely to actually occur.