Singularitarians frequently lament the irrevocably dead and the lack of widespread application of cryonics. Many cryonocists feel that as many lives as possible should be (and in a more rational world, would be) cryopreserved. Eliezer Yudkowsky, in an update to the touching note on the death of his younger brother Yehuda, forcefully expressed this sentiment:

"I stand there, and instead of reciting Tehillim I look at the outline on the grass of my little brother's grave. Beneath this thin rectangle in the dirt lies my brother's coffin, and within that coffin lie his bones, and perhaps decaying flesh if any remains. There is nothing here or anywhere of my little brother's self. His brain's information is destroyed. Yehuda wasn't signed up for cryonics and his body wasn't identified until three days later; but freezing could have been, should have been standard procedure for anonymous patients. The hospital that should have removed Yehuda's head when his heart stopped beating, and preserved him in liquid nitrogen to await rescue, instead laid him out on a slab. Why is the human species still doing this? Why do we still bury our dead? We have all the information we need in order to know better..."

Ignoring the debate concerning the merits of cryopreservation itself and the feasibility of mass cryonics, I would like to question the assumption that every life is worth preserving for posterity.

Consider those who have demonstrated through their actions that they are best kept excluded from society at large. John Wayne Gacy and Jeffrey Dahmer would be prime examples. Many people write these villains off as evil and give their condition not a second thought. But it is quite possible that they actually suffer from some sort of mental illness and are thus not fully responsible for their crimes. In fact, there is evidence that the brains of serial killers are measurably different from those of normal people. Far enough in the future, it might be possible to "cure" them. However, they will still possess toxic memories and thoughts that would greatly distress them now that they are normal. To truly repair them, they would likely need to have many or all of their memories erased. At that point, with an amnesic brain and a cloned body, are they even really the same person, and if not, what was the point of cryopreserving them?

Forming a robust theory of mind and realizing that not everyone thinks or sees the world the same way you do is actually quite difficult. Consider the immense complexity of the world we live in and the staggering scope of thoughts that can possibly be thought as a result. If cryopreservation means first and foremost mind preservation, maybe there are some minds that just shouldn't be preserved. Maybe the future would be a better, happier place without certain thoughts, feelings and memories--and without the minds that harbor them.

Personally, I think the assumption of "better safe than sorry" is a good-enough justification for mass cryonics (or for cryonics generally), but I think that assumption, like any, should at least be questioned.