-=( ---------------------------------------------------------------------- )=- -=( Natural Selection Issue #1 -------------------- Interview : Thomas Ray )=- -=( ---------------------------------------------------------------------- )=- -=( 0 : Contents --------------------------------------------------------- )=- 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. -=( ---------------------------------------------------------------------- )=- -=( Natural Selection Issue #1 --------------- (c) 2002 Feathered Serpents )=- -=( ---------------------------------------------------------------------- )=-