In my earlier post, I argued that cryonics is a kind of emergency medicine. As with all emergency medicine, nobody wants to have to use it. Cryonauts, as the pioneering souls who go into this state of suspended animation are sometimes called, would prefer that cures for aging and age-related diseases be found before they meet their end. But today, when all else fails, cryonics is the best that medicine has to offer.
But if that if so, why do so few people want the procedure for themselves? I do not think it is just a matter of practical concerns such as cost, and I won’t attempt to deal with easily quashed myths that are addressed elsewhere. (For the record, the procedure is usually paid for with a life insurance policy and is affordable for any middle class American that can afford to drink Starbucks coffee twice a week.)
Instead, I want to deal with some of the objections that might give an already informed, life-loving person some pause. I will start with the one which worries me the most: cryonics is hopeless because it fails to maintain the continuity of consciousness. Even if doctors can jumpstart your brain at some point in the future, that will do you no good because you have already vanished out of existence. The revived person will be a new person. Sure, they will be physiologically and psychologically very similar to you, but they will not be you.
Comparing cryonics to general anesthesia may be instructive. When people are put to sleep, they lose all awareness and wake up a few hours later as if no time has passed. I would expect the experience of cryonics to be very much like this, but there is an obvious difference in what is mechanically going on in the brain. The brain under anasthesia is still very much active; the brain of a cryonaut is a motionless piece of glass.
Most cryonicists say that this does not matter. All that matters is whether the information about you is preserved. Since the information—your memories, beliefs, character traits, etc.—is encoded in the structure of the brain, not in its continued activity, we only need continuity of structure. When the activity of that structure resumes, your consciousness will resume. Perhaps we could compare this to a computer that is turned off. Accordingly, those who are vitrified are neither living nor dead, but are rather in a state of suspended animation. They are potentially living but currently inactive.
But my concern with my own continued survival is not about preserving the information stored in my brain. That is such an impersonal way of thinking about the desire to keep on living. I know that some would disagree, and I can’t yet explain the disagreement, but I would very much look forward to living for hundreds of years even if I forgot everything about my past and had to forge a new identity. As it is, I already have a horrible memory of my childhood. This is a sign to me that I care less about who I am than with the fact that I am.
Let us call the hypothesis that cryonic revival results in a duplicate of your old self the Cryonic Duplication hypothesis. A possible response to my concerns is that this hypothesis cannot in principle be tested. Whether it is true or false, we would expect to observe the same things: vitrification -> suspended animation -> repair and revival -> conciousness. Even the revived cryonaut could not answer my concerns because he would be qualtiatively indistinguishable from his old self, whether he was a new person or not.
For some philosophers, this would be the last nail in the coffin where my concerns should be laid to rest. Untestable hypotheses are commonly regarded as pseudo-scientific mumbo-jumbo. If we are going to entertain the Cryonic Duplication hypothesis, we might as well entertain the hypothesis that you are constantly being replaced by duplicates from one moment to the next all throughout your life. And that is a hypothesis which will clearly get us nowhere.
All the same, continuity of activity matters to me, and I can’t entirely explain why. I do not think it is just because the fate of the cryonaut is outside their own hands, or because revival is not guaranteed. Maybe it is because turning to glass, even for a time, falls quite short of the fate I would want for myself. It is possible my confusion—if it is a confusion—is more about time than about consciousness. From the perspective of a being who could perceive a trillion years as if it were a second, the cryonaut would maintain continuity of consciousness. Maybe I am appealing to intuitions rooted in premises that I ought to check, and I welcome such premise-checking in the comments.
But here’s the thing. Even if I am right, cryonics is still a reasonable option. I may not care as much about being revived when I am unsure whether it will be me that is revived, but I find some comfort in the possibility of revival nonetheless. If I were on an exploding Starship Enterprise and the transporter were my only way out, I would use it, even though in that case I am very confident that the person on the other side will be a duplicate.
Even if it is a duplicate in some sense of that term, it is surely better than the alternative.