[extropy-chat] Re: Self replication again (was MARS: ...

[Chris Phoenix]

Mike Lorrey wrote:
 > What is the real difficulty is the fact that you want to make your
 > stuff out of the hardest material around. You can't make parts out of
 > blocks of such raw material unless your tools are also of the same
 > material (or harder). This creates a chicken-egg problem: how are you
 > going to make tools at nano scale out of the hardest material around
 > unless you already have tools of the same material to make those tools,
 > and tools to make those tools, etc...
 >
 > At some point, you have to the hard work that diamond cutters do that
 > is little more than banging one rock against another. They are pretty
 > rocks, but rocks nontheless. In nano scales, you are going to have to
 > make those tools by hand.

Whoa.  Basic misconception here.  MNT is not about chipping away at a 
chunk of diamond to leave a shape.  It is about building a shape of 
diamond bit by bit from individual dimers (or whatever).  The deposition 
"tools" are not tools in the machine-tool sense.  They're closer to a 
hot-melt glue gun or an arc welding tip than to anything with a cutting 
edge.

Given that, I think you haven't challenged my assertion that if you can 
build diamond by MNT deposition, you can build programmable complex 
diamond parts simply by changing the sequence of depositions.

(By the way, I've been told by someone who knows how to machine tool 
steel that you can in fact use steel to cut steel, then use the part 
you've just cut to cut more steel, and rapidly build a very complex 
operation/part from very simple shapes.  Apparently you don't even have 
to mess with tempering and annealing the metal: it just behaves very 
differently under compression than under tension.  So your chicken-egg 
problem doesn't hold for that material.  But that's just a side note, 
because MNT is not about top-down or subtractive machining at all.)

Chris

-- 
Chris Phoenix                                  cphoenix at CRNano.org
Director of Research
Center for Responsible Nanotechnology          http://CRNano.org