Our minds are not alike on this. You’ve explained and I still don’t know what you’re saying in enough detail to respond. Please use more explicit language. How cold of a primate are you talking about? With cryoprotectant or without? How do you propose we avoid cryoprotectant toxicity in the primate study you suggest?
I am not proposing any specific path. I agree with the importance of not forgetting cryonics #2.
Original post mentions “bring someone back from low-damage cryo-preservation” and I tried to add a disambiguation that first “someone” would probably have to be a primate, not human (for various reasons).
Common sense suggests that probably “a mammal”, “a large mammal” and a “primate” could be turning points: until we reach each one, anything beyond that point (like predicting practical applications for humans) is too uncertain to predict.
I think that treating them as prediction-crushing points is safe, because it seems very likely that to revive a large mammal one would need all the knowledge learned from revivial of a small mammal and some more.
I am not sure what should be threshold for true preservation; probably something like long time (hours? days? duration of 10000 normal heartbeats?) without any blood circulation.
Ok, sounds like you are modeling this a bit different from me, probably because I have had relatively more exposure to cryonics ideas. Cryonics (#1) involves perfusion with high concentrations of cryoprotectant to prevent ice formation, and cooling to either −135 C or cooler. Liquid nitrogen is cheap and abundant, so its boiling point is preferable (-196 C) for long term storage. As much as feasible, damage is avoided, but we can’t avoid enough that we can possibly bring people back. So to me cryonics #2 is mainly just an extension of cryonics #1, only the idea is to avoid damage completely—an unachieved goal thus far.
That said, there are other takes on cooling mammals. Hibernation is seen in mammals in nature, and with less concentrated cryoprotectants you can temporarily lower the temperature of mammals to below the ordinary freezing point of water. Some animals such as wood frogs have high ice tolerance, and while their cells don’t freeze there are compartments of their body that do while the cells become concentrated with salts and sugars (and thus relatively dehydrated). But a wood frog cannot handle liquid nitrogen or the glass transition temperature and come back alive.
The chance that cryonics #2 is not achievable by damage reduction (assuming damage reduction is possible) is something I rate rather low, it would require rewriting what we think we know about the brain. Cryonics #1 might be unachievable because of too much damage to be recovered from, but that is uncertain.
I know the pitch and the current practices of cryonics #1. What you said is not new factual information for me, but the way you present it surely helps to understand your point of view.
It is just that with cryonics #2 we can know whether we are succeeding, and with cryonics #1 we can never be sure (and that’s why it can only be applied to dead patients without being considered murder). Personally, I would support legalization of cryonics treatment before natural death—on equal ground with all other forms of assisted suicide (with same informed consent requirements—some safeguards are needed).
I think that scientific development of cryonics #2 would benefit from explicitly saying that it doesn’t know when (and whether) it will be able to offer a verified way to do what cryonics #1 (blindly) tries to do now (maybe succesfully, maybe not—we have no way to find out it yet).
Our minds are not alike on this. You’ve explained and I still don’t know what you’re saying in enough detail to respond. Please use more explicit language. How cold of a primate are you talking about? With cryoprotectant or without? How do you propose we avoid cryoprotectant toxicity in the primate study you suggest?
I am not proposing any specific path. I agree with the importance of not forgetting cryonics #2.
Original post mentions “bring someone back from low-damage cryo-preservation” and I tried to add a disambiguation that first “someone” would probably have to be a primate, not human (for various reasons).
Common sense suggests that probably “a mammal”, “a large mammal” and a “primate” could be turning points: until we reach each one, anything beyond that point (like predicting practical applications for humans) is too uncertain to predict.
I think that treating them as prediction-crushing points is safe, because it seems very likely that to revive a large mammal one would need all the knowledge learned from revivial of a small mammal and some more.
I am not sure what should be threshold for true preservation; probably something like long time (hours? days? duration of 10000 normal heartbeats?) without any blood circulation.
Ok, sounds like you are modeling this a bit different from me, probably because I have had relatively more exposure to cryonics ideas. Cryonics (#1) involves perfusion with high concentrations of cryoprotectant to prevent ice formation, and cooling to either −135 C or cooler. Liquid nitrogen is cheap and abundant, so its boiling point is preferable (-196 C) for long term storage. As much as feasible, damage is avoided, but we can’t avoid enough that we can possibly bring people back. So to me cryonics #2 is mainly just an extension of cryonics #1, only the idea is to avoid damage completely—an unachieved goal thus far.
That said, there are other takes on cooling mammals. Hibernation is seen in mammals in nature, and with less concentrated cryoprotectants you can temporarily lower the temperature of mammals to below the ordinary freezing point of water. Some animals such as wood frogs have high ice tolerance, and while their cells don’t freeze there are compartments of their body that do while the cells become concentrated with salts and sugars (and thus relatively dehydrated). But a wood frog cannot handle liquid nitrogen or the glass transition temperature and come back alive.
The chance that cryonics #2 is not achievable by damage reduction (assuming damage reduction is possible) is something I rate rather low, it would require rewriting what we think we know about the brain. Cryonics #1 might be unachievable because of too much damage to be recovered from, but that is uncertain.
I know the pitch and the current practices of cryonics #1. What you said is not new factual information for me, but the way you present it surely helps to understand your point of view.
It is just that with cryonics #2 we can know whether we are succeeding, and with cryonics #1 we can never be sure (and that’s why it can only be applied to dead patients without being considered murder). Personally, I would support legalization of cryonics treatment before natural death—on equal ground with all other forms of assisted suicide (with same informed consent requirements—some safeguards are needed).
I think that scientific development of cryonics #2 would benefit from explicitly saying that it doesn’t know when (and whether) it will be able to offer a verified way to do what cryonics #1 (blindly) tries to do now (maybe succesfully, maybe not—we have no way to find out it yet).