I purchased a book titled "Entering Space: Creating A Spacefaring Civilization"

by author Robert Zubrin, author of "The Case for Mars" (Fascinating side note:
I saw a paper on Foresight.org listed The Case Against Mars by Drexler, in
which he shows the Moon is a better nearer term target, and I am in agreement
with that).

Mr Zubrin has a chapter which includes Molecular Nanotechnology and how it can
be utilized for space-based programs and colonization. Chapter 10:
Extraordinary Engineering. Pages 235-240 discuss robotics, nanotechnology,
bioengineering, and picotechnology.

Mr Zubrin at first makes a very good description of molecular manufacturing
systems, discussing in depth (albeit without the equations you'd find in a
textbook like Nanosystems) molecular machine systems, gears, etc etc etc
constructed from diamondoid and other ultrahard materials, and their use for
space colonization.

He mentions how the macroscopic self replicating system, while in principle
feasible, is majorly challenged with the need for prefabricated parts, as it
would be far more difficult to implement as you would need machines to smelt
steel and produce wire, whereas, he goes on to show, that nature with cells and
nanomachines would be using (And in the case of cells, currently do) the
natural prefabricated atoms and molecules as their starting points.

Now we get to the part of the chapter that made me go "WHAT??? Is this
serious???"  

I will now quote him:

he starts off here with a positive and realistic statement:

"It certainly sounds like fantasy, but is it? In defense of the nanotechnology
thesis, one can advance the statement that it does not defy any known laws of
physics, and therefore, given sufficient technological advance, it should
become possible. Against it, one can easilly point out the enormous
technological difficulties that must be mastered before nanotechnology becomes
a reality. Furthermore, while nanotechnology may not violate any laws of
physics, controllable (he italicizes this word) self-replicating robots may
well violate the laws of (again italics) biology. Consider that small
replicating micromachines will unquestionably undergo random  alterations, or
mutations, if you will. (He should have noted that synthetic machines that
require special feedstocks and working in industrial vats won't just "mutate")
Those mutations that produce strains that reproduce more rapidly will swiftly
outnumber to insignificance those that don't. Clearly, if the goal is to
reproduce rapidly, it would be to a nanomachine's advantage not to have to
bother with doing work for the benefit of human masters. (Again, he is assuming
out of nowhere, that nanomachines and assemblers will have the capacity to
think on their own, and have desires to disobey 'masters'-humans, which is
unfounded.)

more of his quotes: "Instead, evolutionary pressures will dictate that
nanorobots attend only to their own needs. Those nanorobots that continue to
slave away in obedience to their human-directed programs will not be able to
compete with the wild varieties, and will rapidly go extinct. As the saying
goes, "Live free or die."

Now the following is what MAJORLY caught my eye, and this is the main purpose
of this post, read this:  He goes on to say " There is another reason to hold
nanorobots suspect- we don't observe them. If diamond-geared self-replicating
assemblers could be built, they would be ideally suited for dispersal across
interstellar space using microscopic solar sails for propulsion. If, in the
vast sweep of past time, a single species anywhere in the Milky Way developed
such microautomatons, it long since would have been able to use them to
colonize the entire galaxy. All life on Earth would be based on nanorobots. But
since this is not observed, we are driven toward concluding that either (a)
there is no other intelligent life in the galaxy or (b) non-organic
nanotechnology of the self-replicating micro-Babbage-robot type described by
Drexler is impossible. Since we know that the evolution of intelligent life is
possible, but we do not know that nanotechnology is, I must consider (b) the
more likely alternative. "

Can you believe that??? He is basically saying that since diamondoid
nanotechnology "beings" have not landed on earth and said "Hello!", nanotech of
this type is not possible.

He then discusses biological systems more, and the next time he mentions
nanotechnology, is here:

"For our purposes here, however, it suffices to say that the omnipresence of
organic self-replicating nanospacefarers (bacteria) and the absence of
non-organic nanoassemblers is strong evidence for doubting the feasibility of
Drexler-style nanotechnology."

Then he says: "But maybe nanotechnology isn't impossible; maybe it's just
incredibly difficult. Maybe the reason why nobody else has invented it (he is
again assuming the universe has intelligent, tool using people) is because they
weren't smart enough, or didn't try long and hard enough, or were scared of the
consequences of it getting out of control. Maybe there really is a way to
initiate and control nanotechnology, and it's just waiting for someone to
invent. In every fielkd of endeavor, someone has to be first. Maybe that
someone could be us. Maybe."

Next he goes on to discuss again the positive uses of nanotech for space, ie
the manufacturing of low cost items, and then he says:

"And who knows? Perhaps, in the still more distant future, even greater
capabilities could become possible- building machines not out of atoms or
molecules but from the subatomic particles such as atomic nuclei. Operating on
a scale thousands of times smaller and faster than even nanomachines, such
(italics) picotechnology might draw its energy not from chemical reactions, but
from far faster and more powerful nuclear reactions. The capabilities that such
picomachines would make available could only be described today as sheer magic.
In the meantime, however, my bet is on bioengineering. Life offers us a
tried-and-true type of self-replicating micromachine, and the programming
manual is already in our hands. With our brains and their muscle,
human-improved microorganisms will do some very heavy lifting in the hard work
required to bring dead worlds to life."

I would very much appreciate your comments and critics on his statements.

This is a variant on Tipler's ``answer'' to the Fermi Paradox, which that
the reason why aliens are not trying to communicate with us because Earth
must be the first planet in the galaxy to have evolved self-aware life
capable of high technology and space-travel.  

Tipler observers that the cheapest way for a long-lived technological
civilization to explore the galaxy is to build a few self-replicating
robots (AKA ``von Neumann machines'') who will build and dispatch more
self-replicating robots in every star-system they come across that has
the appropriate materials. (The method is cheap, because once the initial
robots are launched, the only cost to the home system is to wait around
listening for the data to be radioed or lasered back to the home system.)
Since it would only take about ten or twenty million years for such self-
replicating robots to explore the entire galaxy even if they can only
achieve a paltry 0.01 c, and since 10 million years is a miniscule amount
of time compared to even the age of the Earth, let along the galaxy,
Tipler argues that the mere fact that the the galaxy has not been
completely overrun by self- replicating robots, and our asteroid belt
has not been strip-mined out of existence to make more of the thingies,
implies that therefore we are the first self-aware life-forms whose
civilization has evolved to the point of being capable of making said
thingies.

Personally, I consider Tipler's argument to be an extremely weak one ---
about as weak as the so-called ``Anthropic Principle.'' It is a ``Just So''
story that explains away the problem without actually solving it. In my
opinion, Zubrin's extension of Tipler's argument is at least as weak.

-- Gordon D. Pusch  

perl -e '$_ = "gdpusch\@NO.xnet.SPAM.com\n"; s/NO\.//; s/SPAM\.//; print;'

"Gordon D. Pusch" <gdpu...@NO.xnet.SPAM.com> wrote in message
news:a6lf2c0264a@enews1.newsguy.com...

<snip>

Another hole in this argument is the assumption that we would even be aware
of the current or former presence of such exploring machines.

For all we know the asteroid Toro is a Von Neumann machine/complex right
now, and has been for millions of years.  Could we tell?  Similarly,
nano-devices could easily surround us disguised as parts of our biosphere.

[Another hole in his arguement is that all life on earth IS based on
 nanorobots.  e.g.  http://www.nanoword.net/library/def/nanomachine.htm
 -SL]

--
G. Waleed Kavalec
-------------------
Do not act in response to how you wish the world was.
Act in response to how the world is.

news:a6jkt902hlk@enews2.newsguy.com...

This is a false analogy. It is true that living systems do undergo
such random mutations, and that some are beneficial. However, DNA
is a material particularly prone to such alterations (a fact that
may be one of the reasons for its evolutionary success as a coding
mechanism.) There is no particularly good reason to imagine that
nanomachine programs will be similarly prone. Oh, I should say, by
prone I mean both likely to mutate, and likely that a mutation will
be functional and beneficial. Computer programs are orders of
magnitude less prone to mutation than DNA. I would say then that
the likelihood of mutant species of nanomachines that are functional
is vanishingly small, and the likelihood of them overwhelming
the original designed species even smaller. (Especially so with
high grade error checking and correction.)

c) we are the first species to develop nanotech
d) we are the first species to develop nanotech close enough
   to earth for such species to get here.
e) Other intelligent lifeforms are not interested in colonizing
   the universe
f) Other intelligent species have a prime directive -- don't
   violate emerging civilizations
g) Other intelligent species have motives and reasons far beyond
   out possible comprehension.
and so forth.

This statement reminds me of that old question: "have you stopped
beating your wife yet?" If you ask the question in a dumb enough
way you can force an unthinking respondent to answer however you
like. His question is a false dichotomy.

That is an equally dumb statement. We know that both are possible,
so in the absence of any other evidence, we have no idea which is
more likely. It just goes to show that philosophy is rarely a useful
tool for predicting scientific progress.

I just wanted to say that I checked out his book and read the first
part about drexlerian nanomachines not really being possible because
of the need for prefabricated parts; i put the book down then because
that is a point that Drexler uses in his favor and seems right to me.

But, thanks for telling me the rest of his folly!LoL  I think I'll
post this at a seti board!LoL

On 12 Mar 2002 19:06:05 GMT, "G. Waleed Kavalec"

These "counter arguments" all miss an important point I
think. Certainly there could have been undetectable
nanotechnological probes, many civilizations would refrain
from eating up the galaxy with self-reproducing machines,
etc.

The point is that it could only take ONE such civilization
to do this, once, in the entire history of the galaxy, for
the effects to be obvious. This constrains the total number
of civilizations that have existed.

It seems likely that the lifetime of many such civilizations
would be very short compared to the age of the galaxy. The
probability of there being many coincident in time with ours
is therefore low.

--
John Devereux

j...@devereux.demon.co.uk

Well it seemed that at first he was speaking positively about MNT, ie the
prefabricated parts issue makes it easier to build Self-Replicating machines at
the molecular level than at the macro level because we can work with molecules
and atoms.

One idea I read about a macroscale Santa Claus Machine was fascinating: Instead
of molecular mechanical assemblers, it would use huge mass spectrometers, solar
ovens to break the matter down, and electromagnetic fields to join them
together, I don't think that is as producable as mechanosynthesis machinery,
though.

"mutate")"

You've already spotted the flaw in his logic. His entire argument rests
on the
assumption that nanomachines must necessarily be subject to the same
sort of
evolution that governs DNA-based organisms. As others have pointed out,
DNA is
easily prone to mutation, and enough of those mutations are
non-destructive
that evolution works.

Many excellent proposals have been put forth to specifically prevent
evolution
in rationally designed nanomachines. Besides, there are already plenty
of very
complex human artifacts (microprocessors, the Space shuttle, the
Internet) and
none of them mutate.

There's one other weak assumption behind the idea that the nanobots of
other
civilizations should already be here. As Steve Lenhert already pointed
out, we
are already made up of nanobots which have extended their reach to every
reasonable corner of the planet. But only a small number of us has ever
gone
into space. Leaving gravity wells is hard!

Evolution depends on local gradients in the fitness function. There's no
local
gradient for biology that favors going into space. A superbird with a
rocket
engine in his rear end, who could tolerate vacuum, would not enjoy
greater
reproductive success by leaving the atmosphere. We only get there
because we
consciously plan, and even then, it's not always easy to find good
reasons to
do it.

There's a guy named Tom Knight who is researching the area of
engineering
bacteria. He's studying lots of simple bacteria, learning all about what
kinds
of sensors and actuators they have, and learning all about all the
different
chemical processes inside them. His intention is to create a new branch
of
engineering, where we can (within whatever limits biology dictates)
design
bacteria to do all sorts of different stuff: medical treatments, oil
spill
cleanup, very big very slow computers, fun with materials, etc.

news:a6s3aa01d09@enews4.newsguy.com...

What limits would engineered bacteria have? Could they be used to create the
first assemblers?

On 15 Mar 2002, William R. Cousert wrote:

Some of the bootstrap scenarios involve self-assembled biological systems,
produced by whole bacteria or isolates. A lot of this hinges on the
inverse protein folding problem, if you can predict the sequence from a 3d
structure, you can do some very funky stuff already.

I would very much like to see an engineered enzyme, capable of
synthesizing an infinite cumulene strand.

Their direct products will be proteins, and things proteins can
easily make. Proteins are limited in their stiffness, otherwise this
would be the preferred route for nanotechnology in general. Various
other deficiencies of proteins are that they break down when you cook
them, and they melt when you get acid on them, and that sort of thing.
Because they're not stiff, you can't use them to position atoms
precisely. Imagine if you built yourself a drill press and a lathe
and a table-saw out of Play-Doh. You could maybe use those to make
other Play-Doh things, but you couldn't work metal or wood with them.

I don't think they'll be sufficient by themselves, but they might
help. They can manufacture stuff, within the limits mentioned above,
and manufacturing large quantities of stuff (for instance, fuel) could
be a very helpful thing. I remember reading once that somebody had
genetically engineered a bacterium that produces hydrogen. One can
imagine a pond of this stuff in the backyard under a plexiglass dome,
producing the hydrogen to run your car the next day. Actually, I think
the hydrogen yield is actually too small to be practical.

The one addendum to all this is that there are a small number of
cases where cells produce things stiffer than proteins. Animal bodies
synthesize bone, spiders make silk, and there are bacteria that make
little hexagonal metal crystals. How these things are done, I don't
know. Maybe if we can figure out how these tougher materials are made
by a DNA/protein machine, we can do something interesting with that
knowledge. Nobody is doing it that I am aware of, and the idea isn't
that difficult to come up with, so I suspect there's some practical
problem that I don't know about.

[Here is an introduction to "biomolecular Self-assembly"
 http://www.nanoword.net/library/weekly/aa051400a.htm
 There is much nanoscience focused on the question you've posed,  
 the field being known as "biomineralization".  Here is a book:
 http://www.wiley.com/cda/product/0,,3527299874%7Cdesc%7C3026,00.html
 -SL]