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 -=( Natural Selection Issue #1 -------------------- Interview : Thomas Ray )=-
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 1 : Background
 2 : Questions and Answers

 -=( 1 : Background ------------------------------------------------------- )=-

 Thomas Ray is most familiar in the computer virus subculture as creator of the
 "Tierra" software.   In August 1998 he  became a  Professor of Zoology at  the
 University of Oklahoma, with an  adjunct appointment as Professor of  Computer
 Science.

 Tierra is an open-source open-ended ecosystem for digital life forms that  was
 created with the intent of determining the ability and structure of evolution.
 It started with a hand crafted  organism, Ancestor 80, which was set  loose in
 the world and allowed to mutate.  A few million cycles later and the world  is
 teaming with evolved life, from hosts, to viruses and immune hosts.

 Thomas Ray has no association  or formal interest in computer  virus research,
 the relevance of our interview is a peek into methods of legitimate scientific
 exploration into digital life, and some insight as to how evolution works.

 -=( 2 : Questions and Answers -------------------------------------------- )=-

 Q. Remind us how human you are.  What do you do in a normal day?  Where do you
    go for vacation?  What do  you do for fun?

 A. Lately I have been working in my garden, spreading the compost that I  made
    from  the fallen  leaves over  the past  two years.   My  wife  and I  also
    cultivate a moss  garden along the  banks of stream  in our Japanese  style
    garden.  For vacation, I might go to Costa Rica, China, or New Mexico.  For
    fun I listen to music, watch movies, walk, work in the garden...


 Q. To get a background on your  usage of computers, which programs do you  use
    daily?  Have  you ever   been hit  by a   computer virus?   If so,   please
    describe the experience.

 A. I use word processors,  email, web browsers, image  editors, bioinformatics
    tools...  I am not affected by  viruses because I don't use Microsoft  mail
    software.


 Q. It seems quite a leap from tropical biologist to  digital evolutionist, and
    now you've changed direction again  to research in brain architecture.   Is
    there a common thread of interest that drives your research interests?

 A. I suppose that I can  answer that in a variety  of ways.  I think the  most
    common thread is passion.  I do what I have a passion for, and that is part
    of the reason  that I change  direction.  When I  develop a new  passion, I
    move  on.  In  the more  conventional sense,  evolution has  always been  a
    common theme, perhaps until now.  I want to understand the human mind,  and
    my current approach is not evolutionary.


 Q. You maintain a  web page about  the Oklahoma textbook  controversy, where a
    state committee  wanted science  books to  have a  disclaimer stating  that
    evolution was  a "controversial  theory", because  of the  "unproven belief
    that random, undirected forces produced a world of  living things."

    After your research into Tierra, how do you feel about the validity of  the
    theory of evolution?

 A. Tierra  has  strongly  confirmed  my belief  in  evolution.   Tierra  is an
    evolving system, about which we can have complete knowledge.


 Q. In your original implementation of Tierra, Ancestor-80 exploded into a wide
    range of life including parasites, hyper-parasites, "immune" code and  also
    self-optimising code with unrolling loops.   Did you ever expect that  your
    experiment would reveal so much diversity?

 A. It was my dream, not my expectation.


 Q. At the same time, you have done some experimentation with how much the base
    programming language affects  the evolvability of  the system.  How much of
    an effect does the programming language have on the ecology as a whole?

 A. The  base language  has dramatic  effects on  a variety  of  properties  of
    evolution.    However,   a   quick   look   at   the   data   shown   here:
    http://www.his.atr.co.jp/~ray/pubs/oji/node6.html  suggests  that  they all
    show a rich  ecology. The ecology  is a fairly  robust result, at  least it
    seems to be relatively robust to the underlying language.


 Q. Even with your additional of different instruction types, the system  seems
    to reach  an equilibrium  after a  few million  cycles.  Do you think  this
    is a byproduct of an artificial system, or does it indicate how semi-closed
    ecologies operate in general?

 A. I  think natural  systems have  the same  property.   They  tend to  evolve
    towards  relative  stability.  It  is  only on  occassion  that significant
    evolutionary changes occur.   Tierra tends to  get stuck, in  part I think,
    due to its extreme simplicity.


 Q. In your published works you have  referred to the parameters of the  Tierra
    system,  such  as CPU  cycle,  affecting evolution  so  that various  sized
    organisms are favoured over others.   Is it possible to remove  limitations
    such as this from the system, and if so, would that be wise?

 A. Yes,  I  have found  ways  of distributing  CPU  cycles (perhaps  the  most
    critical resource,  analagous to  energy) so  that it  does not arbitrarily
    favor either larger or smaller  organisms.  Now I almost always  run Tierra
    in this "size neutral" mode.  The cost of this choice is that it eliminates
    the conditions that favor parasites.


 Q. What interests me most about Tierra is that given a benevolent ancestor,  a
    wide range of  "violent" parasitic and  viral life pops up out of  nowhere,
    and almost destroys  their environment with  over-replication.  How do  you
    feel about this interplay of good ancestor/evil child in your simulation?

 A. I don't  share your  value laden  interpretations of  the creatures  or the
    processes.


 Q. Have you considered tailoring your system to create spontaneous life of its
    own accord, without the ancestor as a template?  Is it even possible?

 A. I gave some thought to it, but  I never pursued it because it is  not where
    my interests  lied.  However  Pargellis has  done this  quite spectacularly
    with a derivative of Tierra:

    Pargellis, A. N. 1996. The spontaneous generation of digital "life".
    Physica D. 91:86-96.

    Pargellis, A. N. 1996. The evolution of self-replicating computer organisms.
    Physica D. 98:111-127.


 Q. In Network Tierra, there was  a paper produced on multi-cellular  ancestors
    and how they adapted so well to their special environment.   However it did
    not cover as much territory as your earlier papers.  Was there a reason for
    this?

 A. It is  extremely difficult  to analyze  the results  of the  multi-cellular
    work.  I have accumulated data from several years of running multi-cellular
    Tierra, and I  am still analyzing  the results. I  have developed some  new
    analyctical tools, some borrowed from bioinformatics, to help automate this
    difficult analysis. I plan to eventually publish a detailed analysis.

    Please consider  that Tierran  creatures are  machine code.  Have you  ever
    tried to  read and  understand machine  code, or  even assembler code?  Now
    imagine trying to understand  machine/assembler code generated by  a random
    evolutionary  process.   Now complicate  that  by making  the  evolved code
    multi-threaded.


 Q. Do you consider the organisms in Tierra as life, though not as we know  it?
    Or are they just mutated data?

 A. I think of them as a form of life.


 Q. How difficult  was it  to secure  funding for  Tierra?  Have you considered
    publishing a popular-science book on the subject at any point?

 A. Tierra is a  cheap project.  I  prefer to do  cheap science, because  I can
    focus on the science rather than the funding.  It has not been difficult to
    find the funding for Tierra.

    I have given a little thought to  a book on Tierra, but I have  no specific
    plans.


 Q. For those that are interested in continued research in this area of digital
    life, for personal research or careers, what could they do to get involved?

 A. I  think it  is important  to have  a deep  understanding  of  evolutionary
    biology,  and  at  the  same time  to  be  very  comfortable with  computer
    programming.  Then it is probably only possible to pursue this kind of work
    in an academic environment.


 Q. With the rapid  research and implementation  cycle of artificial  life, are
    there any potential dangers arising from its misuse?

 A. It doesn't worry me.  The creatures of artificial life are still  extremely
    primitive, and will probably remain so for the forseeable future.


 Q. Conversely,  what benefits from advances in artificial life and  philosophy
    do you look forward to most?

 A. I think the  greatest potential is  in using artificial  life as an  aid to
    design in engineering.   Human artifacts tend  to lack the  robust adaptive
    quality  of living  organisms.  Artificial  life holds  some potential  for
    introducing those qualities to the things that we create.


 Q. Where do you  see your personal and  professional lives progressing in  the
    immediate future?   What future  projects  of  yours are  there for   us to
    look forward to?

 A. My current research focus is the human  mind.  It is one of the last  great
    frontiers of science.

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 -=( Natural Selection Issue #1 --------------- (c) 2002 Feathered Serpents )=-
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