> In the same essay, Merkle later says:
> While self replicating systems are the key to low cost, there
> is no need (and little desire) to have such systems function in the
> outside world. Instead, in an artificial and controlled environment
> they can manufacture simpler and more rugged systems that can then be
> transferred to their final destination.>
>
> Congratulations to Anders for coming up with a scenario that
> challenges this approach.
Thanks, although I must admit I wasn't interested (or even aware) of the
difference in approach. I have probably been dealing with the biosciences
too long :-)
I actually think we need to learn how to build general purpose nanites
that can work in complex environments, although it is a good idea to
shelter the assemblers. I'm more and more coming to think of my system as
an ant-colony: worker nanites dig our raw materials and extract energy to
feed a pampered central assembler making new hives. It works in nature
and ought to work well in regolith.
> I don't want to restart the flame wars over whether 'positional
> control' is practical for building macro-scale devices or not, and I
> guess I'll just have to wait for Anders to finish his article, but I
> would be very interested to know if he has found anyone working on the
> chemical-signaling approach to nano-construction that he was
> suggesting.
Me too :-) I know some alife people are working on ant-like simulations of
chemical signals, but I would like to do morphogenesis too. For example,
once the colony has reached sufficient size it should react and change its
behvior. This might be acheieved by having each nanite produce slight
amounts of a signal substance, and when the concentration goes above a
certain level the assembler begins to build nanites to build new hives, or
parts for a macroscopic project. Almost exactly what happens in slime
molds. Once the hives or parts are finished, a chemical signal would stop
their production and a new phase could begin. If a hive was damaged, it
would revert to the more basic rebuiilding level before working on the
macro level.
-----------------------------------------------------------------------
Anders Sandberg Towards Ascension!
nv91-asa@nada.kth.se http://www.nada.kth.se/~nv91-asa/main.html
GCS/M/S/O d++ -p+ c++++ !l u+ e++ m++ s+/+ n--- h+/* f+ g+ w++ t+ r+ !y