Chapter 105 17.7 Verbs of life

In the symposium, Langton began to search for the definition of life.Existing definitions of life seem inadequate.In the years since the first symposium, more scholars have studied it.On this basis, physicist Don Farmer proposed a list of characteristics that define life.He said that life has: Patterns in Time and Space self-replicating ability Repository of self-representation (genes) Metabolic functions that make traits persistent Functional Interaction - It's Not Doing Nothing dependent on each other, or able to die Ability to remain stable amidst disturbances ability to evolve

The list has sparked controversy.Because, although we don't consider a computer virus to be alive, it meets most of the above criteria.They are a pattern that can replicate; they contain a copy of self-representation; they intercept cycles of computer metabolism (CPU); they can die; and they can evolve.We can say that computer viruses are the first artificial life to emerge. On the other hand, there are some things that are undeniably biological, but don't meet all the criteria for this list.Mules cannot replicate themselves, and the herpes virus has no metabolism.Langton's success in creating self-replicating individuals also makes him doubt whether people can reach a consensus definition of life: "Every time we succeed in bringing artificial life up to the standard by which life is defined, the definition of life is expanded or changed. For example, Gerald Joyce believed that life is a self-sustaining chemical system capable of undergoing Darwinian evolution. I believe that by the year 2000, a laboratory in the world will have produced a system that meets this definition .Then biologists are busy redefining life."

Langton's definition of artificial life is more acceptable.Artificial life, he said, is "an attempt to extract the logic of life from different material forms".His contention is that life is a process—behavior that is not limited by the manifestations of particular materials.What matters to life is not what it is made of, but what it does.Life is a verb, not a noun.Farmer's list of criteria for life describes actions and behaviours.It's not hard for computer scientists to imagine this inventory of life's signatures as a process of variation.Langton’s colleague Steen Rasmussen, who is also interested in artificial life, once threw a pencil on his desk and sighed: “In the West, we think that the pencil is more real than the movement of the pencil.”

If the movement of the pencil is its essence, the real part, then "artificial" is a misleading word.At the first Artificial Life conference, when Craig Reynolds showed how he could use three simple rules to make countless computer-animated birds fly spontaneously in flocks in the computer, all Everyone can see a real group flying picture.This is artificial birds really flying in groups.Langton summed up the experience by saying: "The most important part to remember about artificial life is that by artificial it is not life but material. Real things emerge. We observe real phenomena. real life."

Biology, the study of the universal principles of life, is undergoing radical change.Biology faces a "fundamental obstacle to the inability to deduce general principles from single instances," Langton said.There is only a single collective instance of life on Earth, and they share a common origin, so it is futile to try to separate their essential and universal features from their lesser ones.For example, to what extent does our view of life depend on the fact that life is composed of chains of carbon structures?If there is not even a single example of life built on a non-carbon chain structure, how can we figure this out?In order to derive general principles and theories of life—that is, to identify characteristics shared by any living system and any life—Langton argued that “we need a whole set of examples to draw conclusions. Since alien life forms are unlikely to Maybe you can send it to your door for us to study, then the only choice is to create another life form by your own efforts." This is Langton's mission - to create another or even several different forms of life, so as to This serves as the basis of true biology, and deduces the reliable logic of the original life.Since these alternative beings are artifacts rather than natural products, we call them artificial life; however, they are as real as we are.

This ambitious challenge separates artificial life from biology at the outset.Biology seeks to understand living organisms by dissecting them, breaking them down into parts.And artificial life has nothing to dissect.So it can only make progress by bringing organisms together, assembling parts into wholes, synthesizing life, not disassembling it.As such, Langton explained, "artificial life amounts to the practice of synthetic biology."