Chapter 30 artificial life

artificial life When Longton finally arrived at the University of Arizona in Tucson in the fall of 1976, he was walking with a cane and a limp, though he needed surgery on his knee and right arm.He was a twenty-eight-year-old college freshman, limping and ashen-faced, and he felt weird to himself, like a clown running out of a circus. "It's weird. Because the fraternities and fraternities at the University of Arizona are full of beautiful people. Also, I'm not in a good state of mind, and I often find myself out of my mind, no matter what I would go off track in the middle of a conversation, and I suddenly realized that I had no idea where people were talking. I had a very limited amount of time to keep my attention. So I felt weird both in my mind and my body."

But on the other hand, Arizona does have a very good side for Longton, which is the university's hospital and top-notch physical therapy and rehab.Langton said: "Physiotherapy at the university really helped me. The doctor insisted that I keep working hard and making progress. I saw that I had to pass the gate, I had to go through a transition to accept where I am now, and work from here, Instead of feeling bad about it, feel good about your progress. So I am determined to accept the sense of exile and weirdness. I still answer questions in class, although sometimes my answers will digress and feel a bit Weird. But I keep trying."

Unfortunately, while his brain and body were recovering, Longton found that Arizona was not the ideal place to study astronomy.He never inquired whether this astronomy capital offers an undergraduate course in astronomy.The university does have a PhD program in astronomy.But to reach the level of advanced doctoral programs, undergraduates must first study physics and then switch to astronomy after graduation.But the only problem for Langton was that undergraduate physics at the University of Arizona wasn't working. “The organization of undergraduate physics is in complete disarray. None of the teachers who teach undergraduate physics speak English. The subjects in the laboratories are primitive and the equipment is poor. No one can tell what we should study.”

Fortunately, he has no regrets.The philosophy department at the University of Arizona is very good, and philosophy attracted Langton because he was fascinated by the history of ideas.The University of Arizona also has an equally good anthropology department, which appealed to Langton because he liked the monkeys at the Primate Research Center.In the first semester, he took courses from these two departments to complete the school's requirements for comprehensive subject credits. Such a choice would be an odd mix to say the least.But for Langton, choosing the courses of these two departments is a perfect combination.He felt it the moment he stepped into Wesley Salmon's philosophy of science classroom. "Selmon has a good view of the subject," Longton said.He soon asked Salmon to be his tutor in philosophy courses. "Selmon was a disciple of the philosopher Hans Reichenbach in the Viennese Circle. These philosophers studied philosophy with a very technical nature. They studied the philosophy of space and time, the mechanism of the quantum , and about the curvature of space-time by Earth's gravity. I quickly realized that I was less interested in understanding one particular and popular view of the universe than in how our worldview evolves over time Yes. I'm very interested in the history of thought. And cosmology just happens to be one of the best avenues for doing that."

Meanwhile, in the Department of Anthropology, Langton heard about the richness of human behavior, beliefs, and habits, the rise and fall of civilizations, the origin of man, and three million years of gradual evolution.Indeed, his advisor in the anthropology department, Stephe Zegura, was a very good teacher and a very good person, with a solid background in evolutionary theory. So, in every way, Langton says, "I was able to immerse myself in the concept of the evolution of information. It quickly became my main interest, and it was very much to my liking." Indeed, his sense of mystery at this time played an overwhelming role.For some reason, he said, he knew he was on the verge of finding the trail of his mysterious feeling.

One of Langton's favorite comics is Gary Larson's The Far Side.This cartoon shows a fully equipped climber about to descend into a gigantic cave in the ground."Because the hole isn't even there!" a reporter shouted with a microphone in hand. "That's exactly how I feel," Langdon laughs.He said that the more he studied anthropology, the more he felt that there was a big crack in the course. "Anthropology is basically a discipline divided into two. On the one hand is a complete and clear fossil record of biological evolution, attached to a rigorous and complete Darwinian theoretical system as an interpretation. This theory includes information coding, and information Mechanisms passed down from generation to generation. On the other hand is the complete and clear fossil record of cultural evolution that anthropologists have discovered. But people who study human culture don't think, discuss, or even listen to theories about the fossil record These kinds of theories. They seem to be deliberately avoiding research in this area."

Langton's impression is that the theory of cultural evolution still retains the imprint of social Darwinism since the 19th century.At that time, people used "survival of the fittest" as an excuse to justify war and social injustice.And of course he could see what was wrong with it.After all, he had spent most of his life opposing war and social injustice, and he just couldn't accept this crack in anthropology.If you can create a true theory of cultural evolution as opposed to the pseudoscience that justifies the status quo, then you might be able to understand how culture actually develops.The important thing is to do something about war and social injustice.

Now, he has a goal worth pursuing.More importantly, he found the feeling.Langton realized that this was not just a question about cultural evolution, but about biological evolution, knowledge evolution, cultural evolution, about the combination of concepts, their recombination, and their transmission across time and space in the human mind, which is all this A combination of everything.At the deepest level, these are all different aspects of the same thing.And more than that, they were like the "Game of Life," or in that sense, like his own mind broken into disjointed pieces.There's a cohesion here, a general story about all the elements coming together and then evolving into structure and then evolving into a complex system capable of growing and surviving.If he can learn to study this cohesion in the right way, if he can abstract the rules of its operation into some correct computer program, then he may be able to capture all the important features of evolution.

"Things finally came together in my mind as a whole concept." But it was just an imagination, an idea that couldn't be articulated. "But that's the only thing that drives me, that's what I've been thinking about." In the spring of 1978, Langton wrote up his ideas in a twenty-six-page paper entitled: "The Evolution of Belief."His basic point is that biological and cultural evolution are two different aspects of the same phenomenon.The "gene" of culture is belief, which in turn is recorded on the basic "DNA" of culture, that is, language.In retrospect, he says, that paper was a rather naive attempt.But that was his manifesto, and his proposal to pursue interdisciplinary, self-designed PhD topics.The proposal would allow him to investigate the problem.And the paper was enough to convince his anthropology course instructor, Zegula. "He's really a really good guy and a great teacher, someone who believed in me," Langton said. "He was the only one who understood what I was talking about. His attitude was: 'Do what you want!'" But Zegula also reminded him that to pursue such a special Ph.D. Invite advisors from other disciplines.As a physical anthropologist, Zegula could not mentor him in physics, biology, and computer science at the same time.

So Langdon began looking around for a suitable mentor during his senior year at the University of Arizona. "That's when I started calling my idea 'artificial life,' which is more or less similar to artificial intelligence," he said. "I had to give it a precise and concise name so that people could understand the scope of its research at a glance. Most people know some artificial intelligence. Artificial life is trying to capture and imitate neuropsychology like artificial intelligence. Capturing and imitating evolution. I'm not trying to accurately mimic reptile evolution, but to capture an abstract model of evolution on a computer and experiment with it. So I use the phrase 'artificial life' to at least open people up to door to this research."

But unfortunately, Longton always got rejected at the first bite.He said: "I talk to people in computer science, but they don't know what I'm talking about. Their field talks about programming, data structures and computer languages. They don't even study artificial intelligence, so the field of computer science Nobody here even wants to listen to me. They look at me and say, 'Your idea has nothing to do with computers.'” Langdon, who has been met with the same cold reception from biologists and physicists, said: "I've been getting the look at you as if you're crazy. It's been a very frustrating situation, especially after my injury, and I can't be sure I'm in What to do, who am I to be.” Objectively speaking, Longton had made tremendous progress by then, not only able to focus, but also physically strong enough to run five miles at a stretch.But he still felt weird, ugly, and unsound. "Because of my nervous system disorder, I don't know what's going on with me. I'm not sure about my own thinking anymore. So this time I'm not sure about my own thinking. No one understands what I'm talking about. This situation did nothing to restore my self-confidence." But he kept trying.He said: "I think this is what I like to do. I like to keep pushing things forward because I know that this research direction I have identified is related to the problems I was thinking about when I was sane and normal before the accident. ... I knew nothing about nonlinear dynamics at that time, but I had a lot of knowledge about emergent properties, about the interaction of parts, about things that many individual factors can't do, but can be done collectively. Strong intuition." Unfortunately, instinct doesn't do the trick.By the end of his senior year, Langdon had to admit that all that hard work had been for naught and he was stuck.Zegura was supportive, but Zegura could not take on the responsibility of guiding Langdon alone.He could only retreat and regroup his forces. During this time, on December 22, 1979, Longton married Elvira Segura, a feisty and outspoken master's student in library science.They met in Steve Zegula's anthropology class. “We were just good friends at first, and then things went downhill.” In May 1980, he graduated with a double degree, largely because he had accumulated so many credits that the university insisted on granting him a double degree.After he graduated, he and Elvira moved into a rented two-bedroom house north of the school. Their lives are stable for the time being.His wife got a very good position in the university library.Langton himself works double hours.He worked as a carpenter for a home improvement firm, a job he found to be a good workout, and as a clerk in a stained-glass shop.Indeed, there was a part of him that made him content to just go on and on."Good glass has a life of its own," he says. "You can put together many small pieces of glass to create the effect of a whole world." But Langton also knew he had to make serious decisions, and the sooner the better.He has been accepted as a graduate student in the university's anthropology department with Zegula's support, but has not yet been granted a specialization in interdisciplinary artificial life.This means that he wastes a lot of time taking courses that he doesn't want to take or doesn't need to take.So, should he just give up research on artificial life altogether? This is absolutely impossible. "I'm disenchanted now, like a convert. I know I have to go, I have to do a PhD in this field. It's just not clear what path to take." What he wanted to do, he decided, was to get a computer and use it to state his thoughts clearly.In this way, he can talk about artificial life, at least to show people some of his ideas.So he took out a loan from the owner of the stained-glass store, bought an Apple II personal computer, and set it up in his cubicle.He also bought a small color TV to use as a computer monitor. "I usually work on the plane at night because I have to go to work during the day. I basically stay up until two or three o'clock every night. For some reason, my brain is always most active and awake during the night Also, my mind is freest and most creative at night. I’ll wake up with an idea in my head, and I’ll get out of bed and try to capture it.” His wife wasn't happy about it.He would hear her voice from the other bedroom: "Come back to sleep! You'll be exhausted tomorrow!" Looking back today, Elvira thinks Langdon's late nights were worth it.But at the time she was annoyed at her husband's use of the home as his office.For her, the house was home, a family home, a retreat from the outside world, but she also knew Langton needed to. Langton's initial foray into artificial life was remarkably simple: just an "organism" not much more complicated than a list of genes. "Each entry on this table is a genotype of this organism, like, how long does this organism live? How often does it produce a new generation? What color? Where does it exist in space? And then There are some environmental issues, like birds flying by and picking up things that are too much in the background. Creatures evolve that way because when they reproduce, they have the opportunity to change." At first, when Langton finished the program, he was delighted to see it working.Organisms do evolve.You can watch them evolve.But he was soon discouraged. "The whole evolution is linear," he said.Organisms are doing unmistakable things.They don't evolve beyond his comprehension.He said: "This is not a real organism. This gene sheet of mine is manipulated by an outside god - the program. Reproduction happens like a myth. What I need is a more closed process - so The process of reproduction happens automatically, as part of the genotype itself." Not knowing where to start, Langton decided to go to the University of Arizona library and do some computer literacy reading there.He tried to find related books using the keyword "self-reproduction". "I brought back a lot of books on this subject!" he said.One reference book immediately caught his attention: The Theory of Self-Reproducing Automata, by John von Neumann and edited by Birx.There is another one, "Cellular Automata Essays", which was also edited by this guy named Box.There is also Cellular Automata by Ted Codd, who invented the relational database.There are many, many books like this. "Wow! That's right. When I found these books, I said to myself: 'Hey, maybe I'm crazy, but these people are at least as crazy as I am!'" He read von Neumann, Burke Kex, Could, and all the books on the subject that he could find in the university library.That's right!It's all there: evolution, the Game of Life, self-assembly, emergent reproduction, all of it. He discovered that von Neumann had been interested in the question of self-reproduction since the late 1940s.At that time, he, Birx and Goldstein had already designed a programmable digital computer.At the time, the concept of a programmable computer was still a novelty. Mathematicians and logicians were eager to understand what such a programmable machine could and could not do. The question was almost unavoidable: Can a machine be programmed to replicate itself? ? Von Neumann would not hesitate to answer in the affirmative, at least in principle he believes the answer should be yes.After all, plants and animals have reproduced themselves for billions of years. At the level of biochemistry, animals and plants follow the same laws of nature as planets.But that fact doesn't do him much favors.Biological self-reproduction is extremely complex, including genes, sex, the combination of sperm and egg, cell division and embryonic development, not to mention the specific and detailed molecular chemistry of proteins and DNA, which were almost completely unknown in the 1940s learn.Machines, on the other hand, are obviously less complicated.So, before von Neumann could answer the question about the self-reproduction of machines, he had to reduce the process to its essence, its abstract logical form.That is, he had to form in his mind the concept that a programmer would build a virtual machine many years later: he had to set aside the specific biochemical machinery and find out where the important features of self-reproduction lay. To get a feel for these questions, von Neumann first conducted a thought experiment.Imagine, he said, a machine floating on the surface of a pond with many machine parts in it.Next, imagine that the machine is a universe builder: Given a description of any machine, the machine can paddle in a pond until it finds the right parts to make the machine, and then builds the machine.In particular, he can reproduce himself if he describes himself to it. It sounds like self-reproduction, said von Neumann.But not yet, at least not quite.The parts of the newly copied machine all fit, but it will not describe itself, which means it cannot continue to copy itself.So von Neumann also postulated that the original machine should have a description copier: a replicable description of the next machine.Once that happens, he says, the next generation has endless opportunities to reproduce.Then there is self-reproduction. Von Neumann's analysis of self-reproduction is very simple as a thought experiment.If we restate a little more formally, what von Neumann is saying is that the genetic material of any self-reproducing system, whether natural or artificial, must serve two distinct fundamental functions.On the one hand, it must function as a computer program, an algorithm that can be run during the reproduction of the next generation.On the other hand, it must function as passive data, a description that can be reproduced and passed on to the next generation. The results of this analysis turned into a startling scientific prediction: a few years later, in 1953, Watson and Clark finally solved the mystery of the molecular structure of DNA.They found that this structure exactly met the two basic requirements pointed out by von Neumann.As a genetic program, DNA encodes the instructions for making the enzymes and structural proteins a cell needs. As a genetic data storehouse, DNA's double helix unwinds and replicates itself every time a cell divides in two.With enviable frugality, evolution has built this dual nature of genetic material into the structure of the DNA molecule itself. But there are other situations.At the time, von Neumann knew that thought experiments alone were not enough.His vision of a self-reproducing machine in a pond is still too concrete, too tied to the concrete material of the process.As a mathematician, he needs very formal and completely abstract theories.The result was a theory of the form that came to be known as "molecular automata."This was suggested by his colleague Stanislaus Uhlan, a Polish mathematician living in Los Alamos.Ulan himself has been thinking about these issues. What Ulan suggests is the framework John Conway used when he invented the Game of Life more than two decades ago.Indeed, Conway was well aware at the time that the Game of Life was merely a special case of molecular automata.Ulam's advice to von Neumann was that, most fundamentally, imagine a programmable universe.In this universe, "time" is defined as the ticking of the cosmic clock, and "space" is defined as individual cells.Each cell is an extremely simple, abstractly defined computer, a finite automaton.At any one time and in any one cell, the automaton will exist in only one of an infinite number of states, which can be imagined as red, white, blue, green, yellow, or 1 , 2, 3, 4, or dead, alive, or whatever.Moreover, every time the cosmic clock ticks, the automaton transitions to a new state, determined by its current state and the current state of its neighbors.The "laws of physics" of the universe are thus encoded in its transition tables: it is the ability to tell each automaton to change according to the states its neighbors might transition to. Von Neumann loved the idea of ​​molecular automata.The system was abstract enough to be mathematically analysable, but rich enough to allow him to grasp the process he was trying to figure out.And it happens to be a system that you can actually simulate on a computer.At least in principle it is possible to do so. In 1954, von Neumann died of cancer, failing to complete his work on cellular automata, but Birx, who was invited to edit all of von Neumann's papers on the study, later edited his work, And filled in the details that von Neumann had not yet had time to complete, and published in 1966 under the name "The Theory of Self-Reproductive Automata".One of the main points of the book is that von Neumann proved the existence of at least one model of molecular automata that can indeed reproduce itself.The model he discovered was extremely complex, requiring a large number of cell lattices, and each cell had twenty-nine different states.This is beyond the capability of any existing computer imitation function.But the fact that such automata do exist answers the fundamental question of principle: Once self-reproduction is seen as a unique feature of living objects, it is possible to enable machines to do the same. When he read all this, Langton says, "he suddenly felt a surge of confidence. I knew I was thinking right." He returned to his Macintosh and quickly programmed a general Functional molecular automata programs.This program enables him to observe the molecular world of colored squares on the screen.The Macintosh has only 64 kilobytes of memory, which means that he can only limit the states of each molecule to no more than eight, which cannot meet the requirements of von Neumann's twenty-nine self-reproductive states, but There is still the possibility of finding a self-reproducing system within this constraint.Langton ran his program to try any state and any transition table he wanted.Each cell in his program has eight states, so he can only get ten to the thirty thousandth power of different gene list possibilities.He set about trying. Langdon knew early on that his quest was not as hopeless as it seemed.In his reading, he discovered that Ted Codd (Ted Codd) had discovered a model with 8 self-reproductive states more than ten years ago.Ted Could was a graduate student at the University of Michigan at the time, working for a guy named John Holland.Since Calder's type was still too complex for the Apple II, Langton thought that perhaps by working with the various parts of the model, he could find a simpler method of operation within the constraints. "All the components of Calder's self-reproductive state act like data pathways," says Langton. That is, four of the eight states of Calder's system function as data, and the other four serve as various Supporting role.In particular, one state acts as a conductor and the other acts as an insulator, which together form the channels that allow data to flow between cells, like copper wires.So Langton started with Calder's "periodic emitter" structure: this is basically a loop, a bit of data is constantly turning around like a clock's minute hand, and at the same time, some kind of arm grows out of the side of the loop, and the period permanently emits a copy of the data that circles in the loop.Langton then starts simulating the emitter, puts a cap on its arm so the signal doesn't run away, he makes the cap by adding a second surround signal and twists the rule table Come on, let it be like this forever.He knew that if he could get his arms out and then back in, making the same loop as the first one, he would have succeeded. The experiment was going very slowly, Langdon was working only a few hours a night, and his wife Elvira was doing her best to be patient.Langton said: "She cares about what I'm interested in and what I think will happen, but she is more concerned about: What do we do? What is the result of what I do? What is the impact of these things on the current family? What will happen to the situation? Where will we be for two years? And it's hard to explain. You've done all this, and what will happen to all you've done? I don't know, I Just know it's important." Longton can only insist on continuous efforts. "I kept making a little progress here, a little progress there. I started making the rules, then perfected it, perfected it, and then cornered myself. Keeping rule sheets filled to fifteen floppy so I can start from another angle after backing it up. So I have to be very careful about documenting what rules produced what behavior, what changed, what I backed up again, and on which floppy backup." It took about two months from when he first read von Neumann to when he finally got the result he wanted.One night, he said, all the pieces finally came together.He sat there watching the circuits stretch out their arms, bend over again, form new, identical circuits, and then go on to form more identical circuits, and so on and on and on indefinitely, like growing coral reefs.He created the simplest self-reproducing molecular automaton to date. "I'm emotionally erupting like a volcano. It's possible, it happened. It's real. Now evolution makes sense. It's not the result of external programs manipulating tables. It's autistic, its biological It's a program in itself. It's a whole system. These things that I've been thinking about, things that I've always thought would be possible to prove if I tried, are now proven to be possible. It's like a landslide of possibility, like You toppled the dominoes, and the dominoes just kept falling, falling, falling."