Cryonics is not Science Fiction

Cryonics is not Science Fiction


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How to solve problems 🦢Why I’m solving Aging

Fiction 📓The Hike

Other Projects Arcadia DEEPWAVE

You can comment on everything. Or give me (harsh) personal feedback.

Made with 💙 by me (how to).

Dedicated to my family.

Status: Draft Half rant, half serious technical discussion

Against Freezing People, or the failure of marketing


I’m a big fan of cryonics. If you aren’t, read this:

I’ve been signed up since there was a European provider - heck, my all-time favorite book is all about it. Short: I love cryonics, and I thought the case for it was made clearly. So I thought.

But the fact is: none of my friends is signed up. Probably the best of the providers, has ~ 500 members. 500! Wait But Whys article was read by probably a million people, and still there is literally 0 money in the field.

I kinda blame him.

Or rather I blame cryonics proponents in general. Let me explain.


When I first stumbled across the website of Tomorrow Biostasis - the first to offer cryonics in Europe, I was excited. I liked a lot of what I was seeing: very simple sign-up, storage in Switzerland, and good company structure. Someone clearly knew what they were doing. But there was one word that stood out to me: “rewarming” (don’t know if it’s still mentioned, but it was there on first launch). I was confused. Isn’t that impossible? I thought we would have to wait for some future nano-wizard-AI-dyson-sphere civilization to upload us? How could they haphazardly make such a promise? I was skeptical.

Pascals Mugging

Cryonics is usually introduced in the following form: You’re gonna die. You could now either burn your body or freeze it. If you burn it, all is lost. If you freeze it, there might be a chance someone could restore the damage - both that coming from the freezing, as well as the one that originally killed you.

Do you see why so few people have done this? It’s the same argument religious groups have made for eons. Give us resources now and we might give you the afterlife.

I’d argue that the problem with this is that normies (non-weird people) have very good intuitions against these kinds of arguments.

Can we warm a cube really fast?

Cryonics is considered sci-fi because reviving a corpse that’s stored in liquid nitrogen sounds hard. So people wave their hands and say “uploading” or “nanobots”.

But fundamentally it’s a very easy engineering and physics problem: the corpse is not frozen (in ideal cases of vitrification (fast cooling) we do not observe ice crystals), so it’s reasonable to claim that there aren’t many differences between you, me and that corpse - it just runs slower. And given that we have brought back people with no brain activity whatsoever, we know for certain that consciousness is ONLY in the structure, not the dynamics of the brain (this was weird for me to accept, but it happens too often in the clinic to be ignored).

So all we have to do is to make the slow corpse run fast again without structural change, a.k.a. we have to heat up this block of stuff, without ice formation.

That’s it.

Just to repeat: we have to figure out how to heat up an arbitrary object of roughly 2m by 50cm by 50cm, that’s -196° C cold to 37° C without any small part either freezing or getting too hot.

You tell me that can’t be done by a small team of good engineers?

Given that the goal is to add a very specific amount of heat energy - not more, not less - to every voxel of the corpse, and we only have two places from which we can intervene - either in time, before the vitrification, and in space, outside the body, I see two general approaches:

Approach 1: Thermal packs

The problem with adding energy from the outside is fundamental: it’s quite hard to add energy to the center, without burning the outside. An oven won’t work, and even microwaves have the same problem. We have to solve a surface-to-volume problem.

But what if we don’t? What if all the thermal energy is stored in the voxel, and released on command? Remember those heat packs in high school? Now it should be possible to build an enzyme or (lipid-based) nanoparticle that changes confirmation on a signal and then releases a bunch of energy. If you tweak the energy release per particle and spread them homogenously in the tissue, you could in principle get very accurate warming.

Approach 2: Thermal thresholds

If it’s too hard to build a thermal battery that remains stable at low temperatures (you don’t want your body to thaw accidentally!), the problem becomes one of adding large amounts of energy from the outside - while avoiding overheating. We basically have to convert a 1 / x function into a straight line, creating a uniform maximum temperature.

I can think of three approaches right now, but there are probably more:

  1. Dampen overheating: embedding the heat source (a particle that converts light, radio, magnetic field change, sound) into a phase change material. PCMs absorb heat while changing phases without increasing the temperature, so they can act like a buffer, and there are a couple of biocompatible ones already in use (maybe not in the high concentration one would need).
  2. Threshold conversion: Imagine a compound that becomes transparent if it gets hot. If you try to heat it by shining light it at, you’ll never reach a very hot state. There are such compounds - called thermochromics - for example, vanadium dioxide has this property, just in the opposite direction of what we want: at higher temperatures, it absorbs infrared light, at lower it lets it through.
  3. image

One molecule that does have what we’re looking for is chlorophyll - yes, the one that plants use to convert light into energy. This is exactly what we’re looking for: a heat source that, as any protein would do, breaks down at high temperatures and becomes transparent. As a protein, it might also break up too late, but it illustrates the principle - thermochromic nanomachines are plentiful and easy to understand. Now we just need to find one that absorbs in spectra where little else of a body does, is widely and homogenously absorbed, biocompatible, and breaks at a temperature between -10 and 30 degrees.