Drexler’s Nanotech Forecast

It’s my opinion that Drexler simply underestimated the basic scientific problems that yet needed to be solved. The discrete nature of atoms and the limited range of geometries that can be utilised for structures at the nanoscale alone make complex molecular machine design extraordinarily challenging. Drug design is challenging enough and all we usually need to do there is create the right shaped static block to fit the working part of the target protein and stop it functioning (OK, I over-simplify, but a drug is a very long way from a molecular machine). Additionally the simulation tools needed to design molecular machines are only now becoming accurate enough, largely because it is only now that we have cheap enough and fast enough compute power to run them in reasonable real time.

It will happen, in time, but there is still a large amount of basic science to be done first IMO. My best guess is that self-assembling biomimetic molecular machines, based on polypeptides, will be the first off the blocks. New tools such as AlphaFold will play an important role in their design.

This took a weird turn in an article that I thought would explore the basic scientific challenges of nanotech and why we don't have it yet. I do think that the erosion of religion has some negative externalities in modern society (ie. lack of easy meaning and direction in life and downfall of local community kinship), but no I don't think that is the main reason why we don't have nanotech specifically. I don't even think that's the primary reason we are more polarized politically now (my current thoughts lean towards changes in information consumption, communication, and trust in institutions).

But specifically nano-printers? Of course people want that, as much as people want quantum computing, fusion energy, brain-computer interfaces, and life-extension. The benefits are obvious, from the money-making opportunities alone. Maybe reality is just disapointing: it's a harder problem than people originally expected without any economically viable intermediate steps (the kind that bolster AI reasearch now) so progress is stuck in a quagmire.  

Nope. Fusion is the tech you want if you want to make arguments like this. Nanotech has actual serious problems, and is going to have to look a lot more like life (using diffusion for transport, using reactions driven by entropy and small energy differences rather than large energy differences, probably some other compromises like modularity) because the world is simply too dirty and noisy machinery driven by large energy differences will find something unintended to react with, and break.

Did Drexler have a mechanism for his 30 year projection?

Let me give an example of the mechanism.  AGI is likely available within 10 years, where AGI is defined as a "machine that can perform, to objective standards, at least as well as the average human on a set of tasks large enough to be about the size of the task-space the average human can perform".

So the mechanism is: (1) large institutions create a large benchmark set (see Big Bench) of automatically gradable tasks that are about as difficult as tasks humans can perform (2) large institutions test out AGI candidate architectures, ideally designed by prior AGI candidates, on this benchmark.  (3) score on the benchmark > average human?  You have AGI.

This is clearly doable and just a matter of scale.

Contrast this to nanotechnology.

See here: 

A nanoassembler is a vast parallel set of assembly lines run by nanomachinery robotics.  So you have to develop at a minimum, gears and dies and sensors and motors and logic and conveyer lines and bearings and...

Note that reliability needs to be very high: a side reaction that causes an unwanted bond will in many cases "kill" that assembly line.  Large scale "practical" nano-assemblers will need redundancy.  

And at a minimum you need to get at least one functioning subsystem of the nano-machinery to work to start to produce things to begin to bootstrap.  Also you are simply burning money until you basically get a mostly or fully functioning nanoassembler - the cost to manipulate atoms is very high doing it with conventional methods, things like STM microscopes that each are very expensive and can only move usually a single head around.  

The problem statement is "build a machinery set of complex parts able to produce every part used in itself".

So it's this enormous upfront investment, it looks nothing like anything people have made before, we can't even "see" what we are doing, and the machinery needed is very very complicated and made using methods people have never used before.  

Note that we don't have macroscale assemblers.  3d printers can't copy themselves, nothing can.  We fill in the gaps in our industrial manufacturing lines with humans who do the steps robots aren't doing.  Humans can't be used to gap-fill at the nanoscale.

I don't see a basis for the "30 year" estimate.  The Manhattan project was "let's purify an isotope we know exists so it will chain react, and let's make another fissionable by exposing it to a neutron flux from the first reactor".  There were a lot of difficulties but it was a straightforward, reasonably simple thing to do.  "purify this isotope", "let nature make this other element (plutonium)", "purify that".  

There were several methods tried for each step and as it so happened almost everything eventually worked.  

Arguably if you think seriously about what a nanoassembler will require the answer's obvious.  You need superintelligence - a form of trees of narrow AI that can learn from a million experiments in parallel, have subgoals to find routes to a nanoassembler, run millions of robotic STM stations in parallel, and systematically find ways around the problems.

The sheer amount of data and decisions that would have to be made to produce a working nanoassembler is likely simply beyond human intelligence at all and always was.  You might need millions or billions of people or more to do it with meatware.

I notice that of the Manhatten and Apollo program, one is actively destructive, while the other is kind of pointless. So while the ability to work together on big projects might have been lost, arguably we were so bad at choosing the project that this is no bad thing.

Have you noticed that an offshoot of the company that makes Canada's bank notes, holds a number of recent patents concerning "mechanosynthesis"? 

Adding to my first comment, another basic problem that at least applies to organic chemical assemblies, is that easily constructed useful engineering shapes such as straight lines (acetylenes, polyenes), planes (graphene ) or spherical/ellipsoidal curves (buckminsterfullerene like structures) are always replete with free electrons. This makes them somewhat reactive in oxidative atmospheres. Everybody looked at the spherical buckminsterfullerene molecule and said “wow, a super-lubricant!” Nope, it is too darn reactive to have a useful lifetime. This is actually rather reassuring in the context of grey goo scenarios.

Excessive reactivity in oxidative atmospheres may perhaps be overcome if we use metal-organic frameworks to create useful engineering shapes (I am no expert on these so don’t know for sure). But much basic research is still required.

To me, bacteria are also nanotech. There is already "Grey Goo" trying to dissolve us and make us into copies of itself...