February 17, 2004

• this is great! my father had this game on his computer when i was a wee lad and it completely baffled me. looking at it now, with some evolutionary biology under my belt, it makes lots of sense. thanks!
• Cool Post, and a classic example of cellular automata. Watching a large random pattern evolve organic shapes should give people the notion that these are somehow related to fractals, which they certainly are. In fact, a large view of the mandelbrot set exhibits the same types of behavior as the shapes evolve through repeated generations of life. The overly chaotic areas dwindle to nothing (or attract to 0 like the black center of the mandelbrot set). The purely deterministic become stable, and do not change unless another object interferes (similar to the inifinity-seeking outer edge of mandelbrot). Then somewhere, right in the middle there is enough chaos and order balanced by the structure and rules (almost necessarily simplistic) to create small, self-sustaining (sometimes reproducing) patterns which can move off to uncharted areas or continue to interact with --and change-- the environment it grew out of. For reference, the first web link is good to see what some stable structures look like. Notice that these exhibit their own behavior that is describable beyond the bounds (and more simply than in the terms of) the rules of the game. The last link (windows download) gives a good impression of the rules in a larger environment (draw a box and fill it randomly). This is one of my favorite subjects (i actually have a B.S. in Complexity, if you can believe that). If the comparison between this and fractals was unclear, I would be happy to explain it further. Sorry, no links, the comment HTML doesnt seem to be working. I tried to compensate with parentheticals.
• lkc - funny, my b.a. in environmental biology showed me different things in the pattern than your b.s. in complexity. of course, what tends more towards complexity and stability than life itself! can you expound on the relationship between evolution and chaos, by any chance? i would love to hear that ... my school did little to combine the two.
• errr...the second link, with the applet, has the glider, exploder, and other shapes.
• [stable 3anana by a boundless monkey population]
• I always think of it as a culture game. If a culture is too stable, the 2x2 blocks come to mind, then they are quickly overwhelmed by the chaos when it hits them, or by a glider from another civilization when it makes contact. The cultures that change in a controlled way generation after generation survive the chaos and the gliders better than the ones that don't, and the civilizations that are too chaotic will eventually self destruct.
• tmb48: Complexity is the notion of self-organization. By stability, I am referring to something with a structure like a salt crystal: A lattice, held at a predictable resonance and an identical structure throughout, in fact its pattern is what completely defines it. Within those confines, life would not be possible. Similarly a very chaotic system (high turbulence currents) the underlying forces are identifiable, but there are no discernable patterns. Because of that, there is no higher order organization, beyond that of turbulence. In both of these examples, scale is irrelevant (once you are considering the lattice structure, or the interaction of water molecules). A pure (purity is important in the deterministic example) salt crystal the size of my pinky will have the same lattice structure as one the size of my body as one the size of my apartment building. Similarly, if the forces of turbulence were approximated in a bucket of water, the molecular interactions would be just as chaotic as in a swimming pool as in the pacific ocean. Now: A human being (or monkey or duckbill platypus or what-have-you) is several orders of organization higher than either one of those. Realistically, I am just a bunch of fluids held together by a few membranes. However, there is the top level of me, who I am and what I say and think, and the underlying system of physiology (nervous, circulatory, endocrine, excratory, digestive), is made up of organs, which is made of tissues, comprised of specialized cells, which in turn have a remarkably similar structure to the top level (our bodies -- cough cough *self-similarity*) in that it is a membrane surrounding its own autonomous functional group, comprising organelles and a reproductive system that carries genetic information, which is a complex of catlytic (near-auto-catalytic, in a roundabout sense -- again reproduction) proteins, which are chains of amino acids, which is the name given to a particular molecular structure, meaning compounds of molecules (and in organic materials, a relatively limited subset, again following certain rules), made of atoms, which are made of a subset of the subatomic particles, which are made of quarks, which last I checked, are made of some yet-undetermined substance.
• At each of those levels, it is meanful to talk about them as their own system with independant elements and properties without having to refer to the underlying level. There is a regularity of structure which gives it deterministic behavior, as well as an undercurrent of randomness. Having propties of BOTH of these systems is what separates life from pure structure, or pure chaos. It is only when both of these properties interact do you find properties that are not completely explained by the underlying system. In a similar manner, we can consider an independantly complex subset of the human body (and, yes, monkeys): the brain. Were it possible to completely map every kind of behavior directly, neuroscience and psychology would be the same. Just as it is meaningful to discuss peoples thoughts and actions as autonomous operators, it is meaningless to discuss thoughts in terms of neurons, even though that is the underlying hardware. Similarly, we can discuss societal trends without ever referring to an individual. As another example, you studied evolutionary biology, which I am sure you know, is quite different from organic- or bio-chemistry. As it would be rather difficult to explain evolution in terms of cis- and trans-reflections. In the game of life, you can see structures, and superstructures maintain a static, unchanging regularity, you can see large areas grow from a tiny seed sustain momentarily then collapse in to nothingness, you can see huge patternless swarms vanish in a generation, and you can see closed systems (it helps if the borders wrap) that behave unpredictably, but never veer into nothingness or a steady pattern. Note, I am not disagreeing with you, I am wondering how this looks to you (like I said, pet subject, though I have been away from it for a while). I tend to see everything in this way and could go on forever about it (as I am sure you could guess), when people look at fractals, or an example like this, there is a natural essence that rings true with people. Very much is understood about "how" it happens, but little is known about "why". I think we both see the same phenomena and interperet through our own knowledge and experiences. (Sorry if points of that were unclear, I havnt tried to discuss anything like this for quite a while).
• Well what's interesting to me is how very much it [kind of]looks like evolution. These little structures immediately try to find ways to stabilize themselves: there are rules that are found again and again independently that will allow a structure to maintain its shape. Similarly, you start with a bunch of GUNK (RNA) and immediately (over about 1 billion years) it starts to separate and realize ways of stabilizing itself into unique but recognizable forms (species). Then you find the semi-stable shapes (the three-pixel line is my favorite) that swing back and forth between one shape and another infinitely. This seems to resemble within-species differences for me: single species maintain enough diversity to allow for changing conditions (new resources in neighboring blocks, for example). And, of course, you get extinction when the shapes just can't figure out a way to live. But, you're right, what's interesting is that it's all pre-determined. There's no randomness here, so it's only superficially like evolution. And there's the fact that evolution tends not towards stability but towards diversity. HOWEVER, the more I think about it the more it probably resembles the very earliest life (what I started with): RNA. You've got tiny little building blocks trying to figure out a way to make themselves work/survive. Eventually, the bad ones die out and you get forms that are recognizable over many repetitions: only certain ones can survive, and all shapes either tend toward these basic shapes or toward extinction. Thus, from ATP we get RNA, and from RNA we get proteins and DNA: these seemed to be suitable building blocks for the rest of life. It would be interesting to impose another level of rules on these new blocks. You could play the game out until it finds stability, then impose a new set of rules in a third dimension on the stable building blocks and see how they work themselves into ever more complex structures. And then, once those become stable, do it all over again... and there, I think, you have the story of life.
• Yep, thats one of the problems of computer simulation, is making the environment adapt itself to add new rules. If it were an ideal simulation, it wouldn't need them (again, understanding the "how" but not the "why" and the completely deterministic manner of computing precludes such a rule). As for extensions of life, I know there are some out there. I have seen one that works in three dimensions, and one that has an additional ruleset based on colors. In my own experience I find that adding extra rules can ruin the simple efficiency of the game, but I saw those variations too long ago to remember if they were effective. My senior thesis was creating an environmental model that had a system of competition to evolve the best (through learning, sexual and asexual reproduction) combination of algorithms that could solve the Travelling Sales(person) Problem. You know, the one where someone has a map of cities and needs to find the shortest path through hitting each city exactly once. My execution of it was not especially good, but I did find that the simplest rules were the most effective in solving the problem. This is a basic system of automata, but more complex ones are used to model weather (seemingly random systems, like turbulence, where a simple equation wont do), and the pattern of disease spread. This, like fractals, I think will come to play a larger role in the future of sciences, as it has been the direction of most since the early 1900's. Its interesting to hear you refer to RNA as the earliest form of life. While the actual definition of 'life' is still iffy (non-politically, I mean the line between virus and amoeba), I always heard basic RNA as being sub-life, somewhere between autocatalytic molecules (not proteins), and a basic cell. If that is being included now, I think thats good, it sounds like its getting closer to nailing down a definition.
• Nice post Pez. And nice comments lkc! I wish I had enough time to write a thoughtful comment on the subject since I have toyed with the subjects for a while but I have to work. Dammit!