The nanotechnology bet

Of all the speculative technologies, the one tied most directly to whether cryonics ever works is molecular nanotechnology.

It is called a bet here on purpose. It is a wager that a capability which is possible in principle, and does not exist, eventually arrives.

Why repair at molecular scale is the linchpin

Revival by either route in how we might achieve revival ends up requiring action at the scale of cells and molecules.

Undo the cause of death. Reverse the preservation damage. Strip the cryoprotectants out during rewarming before they can act.

Each of those means working where the damage actually is, which is inside cells, at the scale of individual structures.

That is the promise of nanotechnology: control over matter at the nanometer scale, a billionth of a meter.

At that scale a small, precise change to a cell can alter its whole fate. It is also the scale at which a synapse is a large object rather than a small one.

Nothing else currently proposed operates there with that kind of precision. Bulk chemistry reaches everywhere and controls nothing; surgery controls precisely and reaches nothing small enough.

The appeal of molecular machinery is that it would be the first tool with both properties at once, which is why so much of the revival argument leans on it.

The clearest example is rewarming. Heat applied from outside arrives unevenly, and that unevenness is the core difficulty in reversible cryopreservation.

A tool acting from inside the tissue does not have that problem, because there is no outside for the heat to travel from.

From a 1959 lecture to a research field

The idea is older than it sounds. In 1959 the physicist Richard Feynman sketched the concept of manipulating matter atom by atom.

His argument was that nothing in physics forbids building and repairing things from the bottom up. It stayed mostly dormant for a quarter of a century.

In 1986 K. Eric Drexler's book Engines of Creation put molecular nanotechnology on the map and gave the field its name.

In its full form it means machinery that positions individual atoms to build, repair or regenerate almost anything, including structures inside a living cell.

Distinguishing what exists from what is promised matters here. Real nanoscale engineering is a working field today.

DNA origami folds molecules into designed shapes. Molecular motors run. Targeted delivery puts drugs where they are needed.

What does not exist is the general-purpose molecular assembler, the machine that could repair arbitrary damage in arbitrary tissue.

The distance between those two things is the whole bet. Everything below depends on which side of that line the future lands on.

What it would buy cryonics

If mature molecular repair ever arrives, the payoff is large and direct.

• Reversing preservation damage. Imperfect vitrification leaves cellular damage that molecular repair could in principle fix before revival.
• Solving rewarming and toxicity together. Warming too slowly lets ice form on the way up, and the agents that prevent ice are themselves toxic. Molecular control addresses both at once.
• Curing the original cause of death. Disease treated at the level of individual cells would make many of today's fatal conditions tractable.
• Reversing the damage of aging. Repair at cellular level could restore tissue to a younger state rather than patch it.

Notice that these are four different problems with one shared solution. That is unusual, and it is why the technology gets so much attention in this field.

It is also why the bet is worth stating plainly rather than assuming. A single capability carrying four problems is a concentrated risk.

Why it is called a bet

The honest part of this article is that the bet can lose, and serious people have argued it will.

The most substantial criticism, argued publicly by chemists in the early 2000s, is that a general-purpose assembler may be unachievable.

The objections were concrete: positioning individual atoms is hindered by the chemistry of the tools doing the positioning, and by how reactive atoms are at that scale.

That debate was never settled by experiment, because the machine at issue was never built by either side. It remains open.

So the correct posture is a wager, not a forecast, and it should be sized like one.

Two things soften the risk. The first is that revival does not depend on this technology alone. The scan-and-rebuild route leans on imaging and computation instead, and where it leads is covered in mind uploading.

If the assembler never arrives, that route is unaffected. A bet with an independent second path is not the same bet as one without.

The second is that partial capability may be enough. Repairing specific, well-characterised damage in preserved tissue is a far smaller ask than a universal assembler.

The most detailed published attempt to specify what would actually be required is Robert Freitas's Cryostasis Revival, which is worth reading precisely because it refuses to hand-wave.

Whether that specification is buildable is the open question, and honest advocates say so. Progress on the pieces is tracked in advancing the field and in our research and development initiatives.

Treating the whole thing as an engineering programme rather than a prophecy is the discipline that keeps this honest, and it is the same stance the field takes toward preservation itself.

An engineering programme can report what it has not achieved. A prophecy cannot, which is the practical reason the distinction matters.

Like every part of the revival story it rests on the same foundation, which is that revival is currently not possible.

What the bet offers is a concrete, physically allowed reason to think the far bank of the bridge can eventually be built. Not a reason to think it already has been.

Further reading

• How we might achieve revival
• Why is revival currently not possible?
• When can we expect revival to happen?
• An engineering approach to a biological problem