Does Cryonics Offer False Hope?

by Ralph Merkle, Ph.D.

Critics say cryonics gives “false hope.” Michael Hendricks, in an article in MIT Technology Review, said

While it might be theoretically possible to preserve these features in dead tissue, that certainly is not happening now. The technology to do so, let alone the ability to read this information back out of such a specimen, does not yet exist even in principle.

...reanimation or simulation is an abjectly false hope that is beyond the promise of technology and is certainly impossible with the frozen, dead tissue offered by the “cryonics” industry.


Unfortunately his piece gave no references, so his words, while bold, lacked any support. I sent him an email and asked “Are there any references you can cite in support of this claim?”

He replied with a comment from... someone. A critical, unattributed someone. But no references.

I asked again, explaining that anonymous critics weren’t exactly what I was interested in.

This time, he sent me a much longer email which provided no references. It was a very nice email, which started by saying “I think we share an understanding of the issues here...” and opined that “ of the last good things we do for future generations is unburden them by getting out of the way.” But still, no references.

I persisted. Finally, he sent me a reference! A link to the site

Wait, what? Michael Hendricks, who said cryonics is an “abjectly false hope” is backing up his claim by giving me a link to the Brain Preservation Foundation? Which recently gave their prize for essentially perfect brain cryopreservation (Aldehyde-Stabilized Cryopreservation, or ASC) to a team from 21st Century Medicine consisting of Robert L. McIntyre and Gregory M. Fahy (

What does the Brain Preservation Foundation say?

It now seems clear that, if the medical and scientific communities were to expend a modicum of effort, a reliable, inexpensive, and scientifically proven procedure for brain preservation could be made available, in short order, in hospitals to all terminal patients that might desire it over the current alternatives (i.e. burial and cremation).

At this point one can only smile. The Brain Preservation Foundation wants the world to adopt ASC, a method developed by 21st Century Medicine that uses glutaraldehyde followed by vitrification. Alcor, on the other hand, uses the vitrification method developed by 21st Century Medicine without using glutaraldehyde. For the non-expert, we’re arguing over which one of two methods, both of which were developed by 21st Century Medicine, we should use. What’s the difference between the two methods? Let’s read the article that won the Brain Preservation Foundation’s prize to find out:

Successful vitrification protocols must therefore make a compromise between minimizing exposure to toxic CPAs (by minimizing CPA equilibration times) and minimizing exposure to dehydration and osmotic stress (by maximizing CPA equilibration times) [17]. For cryoprotecting the brain, the problem of dehydration is particularly severe because of the blood-brain barrier (BBB), which limits the rate at which cryoprotectants can enter the brain, thus causing major osmotic brain shrinkage [10]. For the purposes of connectomics, this dehydration is undesirable because it distorts the brain's ultrastructure and causes difficulties in tracing fine neural processes.

To address the limitations of the previous methods discussed, we conceived of a simple solution that meets our four brain banking goals: aldehyde-stabilized cryopreservation (ASC). We fixed brains using aldehyde perfusion, then gradually perfused those brains with sufficiently high concentrations of cryoprotectant to enable vitrification. The aldehydes immediately stabilize the fine structure of the brain to an extent sufficient for connectomics research, meeting our goal of highquality preservation. Once the brain is fixed, cryoprotectant toxicity and other chemical insults are of minimal concern. Therefore we were able to add cryoprotectant more gradually and to include a surfactant to accelerate CPA introduction by breaking down the BBB, allowing us to achieve dehydration-free vitrification.

Rather obviously, if you want to cryopreserve someone you’d rather not perfuse them with glutaraldehyde. It’s a fixative. On the other hand, if you don’t use glutaraldehyde, then you’re going to get dehydration and shrinkage, which means you won’t get the pretty pictures that neuroscientists like.

So, what’s your preference? Better pictures, or better biological viability? The neuroscientists want the pictures. Alcor has traditionally worked to achieve better biological viability.

Ultimately, Alcor members are going to make the choice. So, what do you, the members of Alcor, want? Do you want Alcor to add glutaraldehyde to our solutions, and deliver the better pictures that Michael Hendricks wants? Or do you prefer our current protocol, without glutaraldehyde, which results in dehydration and shrinkage? To quote the article that describes the winner of the Brain Preservation Foundation’s prize: Alcor’s current protocol “...causes difficulties in tracing fine neural processes.” Or, to be more accurate, Alcor’s current protocol makes it more difficult for existing technologies to trace fine neural processes. Molecular nanotechnology based methods should have no difficulty in tracing fine neural processes, whether or not they suffer from dehydration and shrinkage.

Also, Alcor and associated laboratories are currently exploring methods to deliver vitrification solutions to the brain without shrinking and dehydration by modifying the blood brain barrier. If this work is successful, we may be able to offer better biological viability and better pictures.

As an expert in molecular nanotechnology, I’m happy to say we should be able to revive you whichever protocol Alcor chooses. The cryobiological experts who advise Alcor favor the use of Alcor’s current protocol (or we would have changed it). I hesitate to name those experts, as officially the Society for Cryobiology still has bylaws that call for the expulsion of members who are “engaged in or who promote” “...any practice or application of freezing deceased persons in anticipation of their reanimation.”

As for the critics: now you’ve seen what happens when you ask one to back up his claim that cryonics offers “false hope.” He cites the research done by the cryonics community, research which favors cryonics. In my experience, Hendricks is one of the more honest and scientifically educated critics. When asked to provide references, he understands what he needs to provide and realizes he has nothing. Less educated or less honest critics would have provided “references” to substandard or dishonest articles.

But the fact remains: there are no published articles in the scientific literature that provide even one technical reason for believing that cryonics won’t work. Not one. Hendricks couldn’t find any. Neither has anyone else (see Alcor FAQ item What do experts say?). The simplest explanation for this remarkable absence is that cryonics, when carried out under reasonable conditions, actually works.

Someday, Alcor’s patients are going to start waking up. I wonder what the critics will say then? Perhaps they’ll retract their claims that cryonics offers “false hope.” Unfortunately, by that time many people will have died of the false despair being spread by the critics.