[extropy-chat] Why no assembler design?

[Eugen Leitl]

On Sat, Nov 15, 2003 at 09:47:12PM -0500, Dan Clemmensen wrote:
> Hal Finney wrote:
> 
> >4. Designing an assembler is relatively straightforward and it is clear
> >that it could be done today with a modest effort, but since there is no
> >way to build the resulting device, no one wants to go to the effort of
> >coming up with a complete assembler design.
> >
> >
> >Answers 3 and 4 assume that merely designing an assembler is pointless;
> >rather, effort should be devoted to designing an assembler which can be
> >built from simpler tools, which is much more difficult.  Nevertheless it
> >would seem that if the situation were close to case 4, it might be a
> >worthwhile exercise just to make the technological potential more obvious.
> >
> > 
> >
> I've always assumed point 4: simple to design, but we do not know how to 
> build it.
> 
> This changes the problem: dont merely design an assembler. Instead, 
> design an assembler that can be built with simpler tools.
> 
> This in turn means that your problem statement is not quite correct. We 
> should nto try for a complete design as a proof of concept and an 
> inducement. Rather, we should be specifically trying to generate a range 
> of assembler designs that may be achievable using simpler tools. If we 
> keep generating valid assembler designs, perhaps we will find one that 
> is buildable. Thus, we do not want the best assembler. Instead we want 
> an assembler that can be built, no matter how poor this assembler is, as 
> long as this assembler can build a better assembler.
> 
> Put it another way: the bootstrap problem is the only hard problem.
> 
> In particular, we do not need an sssembler that can operate in a hostile 
> envoronment. We are free to pick any arbitrary environment for the 

Unless you're trying to build a weapon ;)

> bootstrap, as long as we can create that environment using macro- or 
> micro- technology. Create the environmant, build the assembler using 
> micro techniques, and then use the assembler to build a more robust 
> assembler that can operate in more general environment.
> 
> For example, assume that the bootstrap assembler is built from nanotubes 
> and that it will only operate in a hard vacuum, on a perfect diamond 
> surface. Fine. We know how to create a hard vacuum and a diamond 
> surface. If we can use this incredibly expensive system to build a more 
> robust system, we win. I see a sequence of progressively more robust and 
> sophisticated systems, culminating in a system that can build the 
> critical elements of its own environment.
> 
> Here is a possible bootstrap sequence:
> 
> Nanotube assembler in a hard vacuum on a diamond substrate, with a 
> highly ordered feedstock (benzene precipitated on diamond?) controlled 
> and powered via an external laser and an external computer. This system 
> may use MEMS structures to create nanotube feedstock.

There are many designs possible. You could use a dip-pen lithography of
monomer, and photopolymerize with an UV SNOM head. Or even just try to
scale down an inkjet with a microfluidics head. 
You could feed monomer through
a bucky lumen, and use mechanical pressure and/or voltage spikes to
polymerize. You could just make SWNT/MWNT in a large continuous process
(electroheat a block of graphite (HOPG would be better, probably) and
quench it in cold water; lather, rinse, repeat: 40% yield), and
use chemical (aza-substitution), physical (charge-separation) and 
nanorobotics (well, grad students as flesh robots) means to sort them 
into bins.

This is off the top of my head, there must be zillions of other variants.
 
> Nanotube-based factory. Similar to the above, but with a number of 
> specialized nano-machines to generate functionalized nanotubes as 
> feedstock to the assemblers.

You can just use sorting here. Not too many kinds of a carbon nanotube are
there, if the size is small, and we're not looking for perfect specimens.
 
> Diamondoid-producing nanotube factory. The nanotube factory can now 
> generate a small set of diamondoid parts.

You can separate higher diamondoids from natural sources. It should be
possible to functionalize their surface to make them sticky, and use
nanorobotics to map a library and assemble those which are complementary.
 
-- Eugen* Leitl <a href="http://leitl.org">leitl</a>
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ICBM: 48.07078, 11.61144 http://www.leitl.org
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