Path: utzoo!utgpu!news-server.csri.toronto.edu!mailrus!cs.utexas.edu!usc!apple!amdahl!kp
From: kp@uts.amdahl.com (Ken Presting)
Newsgroups: comp.ai
Subject: Re: "Sensor Evolution"
Summary: Check out Ribosomes, Antibodies, and Scientists...
Keywords: Artificial Life, sensors
Message-ID: <8bn=02lt94=p01@amdahl.uts.amdahl.com>
Date: 21 Mar 90 20:36:53 GMT
References: <782@berlioz.nsc.com>
Reply-To: kp@amdahl.uts.amdahl.com (Ken Presting)
Organization: Amdahl Corporation, Sunnyvale CA
Lines: 57

In article <782@berlioz.nsc.com> andrew@dtg.nsc.com (Lord Snooty @ The Giant Poisoned Electric Head       ) writes:
>An article in "EE Times", March 19th, discusses projects on Artificial Life.
>Perhaps the most radical proposal (by Cariani of Eaton-Peabody Labs, Boston)
>is for a system which "evolves its own special sensors" in response to
>the dynamic environment.
>
>This piques my curiosity because it sounds impossible. Given (and it's a
>big given) that sensor assembly technology were available to an automaton
>in any case, how the hell would it know what to sense, given the
>"requirement"? I take it that the "requirement" would be some kind of detection
>of nonseparability in classification of environmental variables... which is
>probably possible (but could also be highly nontrivial!).
>
>Despite my incredulity at the proposal, automatic sensor (and indeed
>effector) generation is part of what evolution is all about; the wing, the
>eye, etc. So the existence proof is to be found in Nature.
>
>But how to actually engineer this?

(I hope you're not put off by wild speculation...)

A look at small-scale selection systems may be helpful.  When I think
about artificial life, I always think of the early, chemical stages of
evolution.  Ribosomes are made of the same material on which they
operate, so they are nicely analogous to programs in a machine with
integrated data and program storage.  A ribosome is sort of an enzyme
made of RNA.

An enzyme does discriminate between objects in its environment, which is
one important part of "perception".  Of course, there is no intentionality
or deliberation involved.  And there are only two categories - "(my)
substrate" and "not (my) substrate".  It may be a problem that enzyme
recognition of a substrate is unconscious, but on the other hand, there
is no confusing *homunculus* suggested by enzyme behavior.  Of course,
no particular ribosome would "design" a new sensor for itself, but that
is the whole point of imbedding them in a selection system.

The immune system generates a huge variety of cells using regions in the
genome which are very specifically "optimised" to be *inaccurately*
expressed.  These cells then make antibodies, which randomly match
non-self molecules, and are cloned when one of them scores a hit.  This
is a case of a complex system (the body) using a generate-and-test
strategy to create new detection devices.  Also unconscious, but at
least this system does not have to be imbedded in a population to show
something simliar to selection.  (this is a lousy description of a
beautiful phenomenon, but any immunology text would probably give an
accessible account)

Finally, natural scientists are always building new machines to detect
phenomena of new types.  Whether selection occurs among scientific
theories is perhaps a matter of metaphor rather than fact, but it is
an intriguing idea.

My bet is on the ribosomes.  You gotta hand it to those little buggers.
The first digitally controlled self-assembling machine.

Ken Presting