From: louis@hound.cs.indiana.edu (Sushil)
Newsgroups: sci.nanotech
Subject: Re: Evolution and nanotech
Date: 15 Sep 92 21:06:45 GMT
Organization: Indiana University, Bloomington


	The survey posted by JoSH started me thinking about evolution, 
nanotech and scary scenarios. Glad to see a thread already here.

------------------------
In article <Aug.31.01.48.26.1992.24252@planchet.rutgers.edu> radford@cs.toronto.edu (Radford Neal) writes:
>
>If we are randomly searching for rare, highly-beneficial mutations,
>then it shouldn't matter whether we have sex or not. Once a single
>organism is produced with the good mutation, it's descendents should
>quickly out-compete the others.

	Sexual recombination matters. Think about TWO (2) beneficial
mutations A and B. For an individual to have both in asexual
populations, A must occur in an individual followed by the occurence
of B in a descendant of that individual (or vice-versa).
	In sexual populations, A and B can occur in unrelated
individuals and come together thru sexual recombination in their descendants.

[ See the "evolution of sex" by John Maynard Smith, Cambridge
University Press, 1978.  for details.]

	The other point about mutations is that however small you make
the probability of mutation, as the population grows (assuming self
replicating assemblers) the probability that the POPULATION contains a
mutant individual, increases. Sexual recombination just makes the
spread of benificial mutations faster. Self replication can be very
dangerous. Small populations and mutation rates very very close to zero
are neccessary.

From: szabo@techbook.com (Nick Szabo)
>I conclude that evolution can be programmed, but also can be easily
>designed out of a machine.  It is probable people will purposefully
>design evolving machines at some point, just for a neat hack if for
>no other reason.

>Ref: _Arfificial Life 2_ (2nd Conference on Artificial Life, Santa Fe
>Institute


	If fidelity is not guaranteed at 100%, copying errors and
mutations will exist in large populations. In addition, for natural
selection to start working you need replicators/assemblers.  IF you
stop copying/replicating you stop evolution.  Even with replication,
there are various ways of controlling runaway evolution, including
restricting the parts needed for copying. This has already been
discussed on sci.nanotech.  If someone wants to develop assemblers
that can replicate with EASILY available material, I'd suggest Space
Station Freedom, or its nanotech made descendants, or the moon with
all the safegaurds that Drexler proposes and any others that come to
mind.....(At least one use for SSF).

	This IMHO is not as bad as the much more scary scenario of the
creation/engineering/evolution of an Artificial Intellect in an
electronic medium. Electronic (and mechanical) nano-supercomputers are
going to make AI much easier to achieve ;-) Avoiding philosophical
issues, imagine an AI proliferating and learning on the net. It's rate
of learning and evolution (and it WILL evolve because copying is so
easy) will be phenomenally fast. How can you stop replication?
Electronic books will make things easier to learn. Pretty soon,
perhaps a few days/months maybe years, such an AI may know more than
the whole human race. This may not happen as quickly without nanotech
computers, but IMHO that it will happen.  Computer viruses already
exist and examplify early electronic fauna.

From: tomk@netcom.com (Thomas H. Kunich)
>Somewhere I read that things evolve as they must. That
>is an important distinction in evolution. There are many non-competitive
>mutations that occur in species that are not weeded out because there
>is no survival pressure. Color distinctions are often involved in
>this sort of thing. Might not nanotech devices have similar problems?

	Are you talking about the neutral theory of molecular evolution?
Neutral mutations that do not affect the fitness of the organism.

>So 'beneficial mutation' doesn't have anything to do with 'competitive
>advantage' except in certain circumstances.

	Beneficial mutations, by definition, confer a competitive advantage a
higher fitness. Neutral mutations do not. 
	

|=============================================================================|
Sushil Louis					GAs in Design/Adaptive systems
louis@cs.indiana.edu				------------------------------
Department of Computer Science			Design is an art
215 Lindley Hall 				Natural Selection, an artist
Indiana University				------------------------------
Bloomington, IN				
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