The probability that cryonics will work likely exceeds 85%, discounting dystopian futures, assuming a good quality of cryopreservation, and assuming that MNT is developed more or less as expected.
The usual error made in these analyses is to imagine many different kinds of “disasters”, all correlated, that could cause cryonics to fail, and then multiply their probabilities together. But because all the probabilities are correlated, the resulting overall probability is unrealistically low, often by orders of magnitude.
The only real problems are (a) information theoretic death occurs for one reason or another or (b) the necessary technology to restore you to full health is never developed and applied.
Causing information theoretic death is actually a lot harder than people think. Scrambling information is not destroying information, as cryptanalysis tells us, and the laws of physics are reversible. This whole issue is discussed in Cryonics, Cryptography, and Maximum Likelihood Estimation.
The ability to arrange the atoms from which you are made as might be required to restore you’re cryopreserved self to a fully functional and healthy state should be developed in the next several decades. Betting your life that Molecular NanoTechnology (MNT) will not be developed seems singularly foolish given the available evidence.
In today’s modern cryopreservations carried out under reasonable conditions the patient’s brain is vitrified, making it hard to argue that information theoretic death occurs during cryopreservation. Likewise, it is hard to argue that information theoretic death could occur during storage at the temperature of liquid nitrogen. This leaves us arguing over whether cryonics will work when the cryopreservation is carried out under unreasonable (poor) conditions, if Alcor itself will survive, or if the future will suffer from some dystopian disaster so awful that it makes all our efforts moot.
The most effective way to insure a good cryopreservation is to move close to Alcor before being cryopreserved. Betting your life that Alcor will spontaneously crash and burn seems remarkably pessimistic when the historical record shows that a much smaller Alcor successfully survived many challenges since 1972 and today’s Alcor is much better able to survive any future challenges. This is even more true when we can shift the odds in our favor by pitching in and helping insure that Alcor survives, rather than sitting on the sidelines and simply hoping. Dystopian futures seem to be more a projection of an individual’s own depression, rather than accurate forecasts of the future.
Which leads to the conclusion that cryonics actually has a high probability of success.
You write off as 0% likely a whole lot of things I would put at at least 20%, such as alcor falling apart and nanotechnology not being developed. Those things add multiply up.
I have a vague impression that “the laws of physics are reversible” is not actually true.
Two meanings of “reversible” here: ‘can be run in reverse’ vs ‘from looking at the current state we can determine all prior states’. I believe merkle was using the second meaning and you’re arguing against the first.
The 2nd law doesn’t argue against the first meaning, that microscopic events look the same in both time directions. That’s true. The reason that doesn’t generalize to macroscopic events (i.e. the 2nd law arguing against the second meaning) is illustrated by diffusion. Suppose you have a sufficiently hot interface between two pure metal slabs- there’s lots of vacancies and the atoms are dancing around in the crystal structure. At the interface, you might have a vacancy surrounded by three atoms of metal A and two atoms of metal B. Each atom is roughly equally likely to hop to that vacancy, but it’s 60-40 that an atom of metal A will move there instead of an atom of metal B. The result is that a sharp interface becomes a diffuse interface until eventually you have one slab of both A and B, with local distributions of A and B in thermal equilibrium with each other. Once this has happened, you won’t be able to tell which side of the slab was originally A and which side was B.
What makes cryonics work is that it’s very cold, which means that diffusion happens on massive timescales. The main question I have about information-theoretic death is how long someone’s brain has to be dead at room temperature for information to be permanently lost. The long-term damage of even a few minutes of anoxic deprivation before standard revival is massive. What information you need from a frozen dead cell to make a functional live cell isn’t well known- if it’s just the knowledge that neuron A is connected to neuron B, we’re in good shape. If it’s what the local ion distributions were in the cellular soup and you let them diffuse for thirty minutes, it might be impossible.
Well, there’s also acoustic fracture events, which Alcor cops to in their FAQ but sort of downplays the significance of. Even though vitrification prevents ice crystal formation, fractures occur at just a few degrees below the glass transition. Feeling lucky about the odds of checking and correcting the damage to 10^15 unmapped connections?
If cryonics is not performed extremely quickly, ischemic clotting can seriously inhibit cortical circulation, preventing good perfusion with cryoprotectants, and causing partial information-theoretic death. Being cryopreserved within a matter of minutes is probably necessary, barring a way to quickly improve circulation.
The probability that cryonics will work likely exceeds 85%, discounting dystopian futures, assuming a good quality of cryopreservation, and assuming that MNT is developed more or less as expected.
The usual error made in these analyses is to imagine many different kinds of “disasters”, all correlated, that could cause cryonics to fail, and then multiply their probabilities together. But because all the probabilities are correlated, the resulting overall probability is unrealistically low, often by orders of magnitude.
The only real problems are (a) information theoretic death occurs for one reason or another or (b) the necessary technology to restore you to full health is never developed and applied.
Causing information theoretic death is actually a lot harder than people think. Scrambling information is not destroying information, as cryptanalysis tells us, and the laws of physics are reversible. This whole issue is discussed in Cryonics, Cryptography, and Maximum Likelihood Estimation.
The ability to arrange the atoms from which you are made as might be required to restore you’re cryopreserved self to a fully functional and healthy state should be developed in the next several decades. Betting your life that Molecular NanoTechnology (MNT) will not be developed seems singularly foolish given the available evidence.
In today’s modern cryopreservations carried out under reasonable conditions the patient’s brain is vitrified, making it hard to argue that information theoretic death occurs during cryopreservation. Likewise, it is hard to argue that information theoretic death could occur during storage at the temperature of liquid nitrogen. This leaves us arguing over whether cryonics will work when the cryopreservation is carried out under unreasonable (poor) conditions, if Alcor itself will survive, or if the future will suffer from some dystopian disaster so awful that it makes all our efforts moot.
The most effective way to insure a good cryopreservation is to move close to Alcor before being cryopreserved. Betting your life that Alcor will spontaneously crash and burn seems remarkably pessimistic when the historical record shows that a much smaller Alcor successfully survived many challenges since 1972 and today’s Alcor is much better able to survive any future challenges. This is even more true when we can shift the odds in our favor by pitching in and helping insure that Alcor survives, rather than sitting on the sidelines and simply hoping. Dystopian futures seem to be more a projection of an individual’s own depression, rather than accurate forecasts of the future.
Which leads to the conclusion that cryonics actually has a high probability of success.
You write off as 0% likely a whole lot of things I would put at at least 20%, such as alcor falling apart and nanotechnology not being developed. Those things
addmultiply up.I have a vague impression that “the laws of physics are reversible” is not actually true.
Well, it’s not like the Second Law of Thermodynamics is a law of physics. It’d be in the title or something.
Two meanings of “reversible” here: ‘can be run in reverse’ vs ‘from looking at the current state we can determine all prior states’. I believe merkle was using the second meaning and you’re arguing against the first.
Though I don’t know very much about this.
The 2nd law doesn’t argue against the first meaning, that microscopic events look the same in both time directions. That’s true. The reason that doesn’t generalize to macroscopic events (i.e. the 2nd law arguing against the second meaning) is illustrated by diffusion. Suppose you have a sufficiently hot interface between two pure metal slabs- there’s lots of vacancies and the atoms are dancing around in the crystal structure. At the interface, you might have a vacancy surrounded by three atoms of metal A and two atoms of metal B. Each atom is roughly equally likely to hop to that vacancy, but it’s 60-40 that an atom of metal A will move there instead of an atom of metal B. The result is that a sharp interface becomes a diffuse interface until eventually you have one slab of both A and B, with local distributions of A and B in thermal equilibrium with each other. Once this has happened, you won’t be able to tell which side of the slab was originally A and which side was B.
What makes cryonics work is that it’s very cold, which means that diffusion happens on massive timescales. The main question I have about information-theoretic death is how long someone’s brain has to be dead at room temperature for information to be permanently lost. The long-term damage of even a few minutes of anoxic deprivation before standard revival is massive. What information you need from a frozen dead cell to make a functional live cell isn’t well known- if it’s just the knowledge that neuron A is connected to neuron B, we’re in good shape. If it’s what the local ion distributions were in the cellular soup and you let them diffuse for thirty minutes, it might be impossible.
Well, there’s also acoustic fracture events, which Alcor cops to in their FAQ but sort of downplays the significance of. Even though vitrification prevents ice crystal formation, fractures occur at just a few degrees below the glass transition. Feeling lucky about the odds of checking and correcting the damage to 10^15 unmapped connections?
If cryonics is not performed extremely quickly, ischemic clotting can seriously inhibit cortical circulation, preventing good perfusion with cryoprotectants, and causing partial information-theoretic death. Being cryopreserved within a matter of minutes is probably necessary, barring a way to quickly improve circulation.