Life, Artificial Life and Generalized Artificial LifeTu Xuyan

Hon. President of Chinese Association for Artificial IntelligenceChairman of Steering Committee ofCAAI

Professor and Advisor of School of Information Engineering ofUniversity of Science andTechnology Beijing, BeijingEmail: tuxuyan@sina.com

Abstract-In this paper, the concepts of "Life", "ArtificialLife" and "Generalized Artificial Life" and the problem "IsArtificial Life true Life?" are discussed.

I. INTRODUCTION

I visited Arizona University on invitation and reported"Generalized Artificial Life" in April, 2003. In discussion, astudent put a question, which is very interesting and difficultto answer, "Is Artificial Life true Life?"To answer this question, we need to discuss the following

four questions:1) What is Life?2) What is Natural Life?3) What is Artificial Life?4) What is Generalized Artificial Life?

II. WHAT IS LIFE

The first question is "What is Life?""Life" is popular and profound. On one hand, it's

well-known that everyone has Life; On the other hand,people have been exploring Life's mystery in all ages.

Our "Life viewpoint" is as follows:A.Life originatedfrom Biology

The concept of "Life" originated from "Biology".Because consciousness depends on being, subjectivecognition is the reflection of objectivity. Since it hasBiology on the earth, such as human, other animals andplants, people have the concept of "Life" in cognition.B.Life bases on substance

The foundation of "Life" is "substance". Life is activatedsubstance and its movement process. Biology is live object,namely living substance. Therefore, "Life" means Biologyand its active process. For example, human and the totalprocess of birth, old age, illness and death. "Activity" isbiological characteristics, function and behavior, such asreproduction, heredity, growth, metabolism, evolution,intelligence and emotion.C.Life indwells system

"Life" indwells system. System is composed of organizedelements. Biology is living and active system. Life activity

is dynamic process of Life system, whichcapability of Life system and not localindividual elements.D.Life is controlled by information

is the wholecapability of

"Life activity" is controlled by information. Gene isintemal basic information of Life system. Life activityprocess is dynamic, which is controlled by intemal Lifeinformation and exterior environment information. It's amotive process of substance stream and energy stream inLife system.E.Life's pith is Intelligence

Life's pith is intelligence. Intelligence means intellect andcapability. Human is intellect animal, "Human is thecleverest of everything on earth". The clevemess is inintelligence, such as multi-layer intelligence characteristicsof auto-reasoning, auto-association, auto-learning,auto-identifying, auto-searching excellent, auto-stabilizing,auto-organizing, auto-reproduction, auto-evolution andself-determination, activity, agility, flexibility andcreativity(thinking, apperceive and behavior).F.Life has abundant emotion

The abundance of "Life meaning" is emotion. Emotionmeans sensation and mood. Human is a kind of emotionalanimal. Being the highest level life system, the delicateactivity is having abundant emotion, such as love, hate,favor, hatred, pleased, anger, grief and happiness. Sincehuman have intellect and emotion, people have abundantlife.Maybe we can experience what Life means from the

viewpoint of above "Life view".Of course, the world is in changing and developing

movement and people's cognition and viewpoint isevolutive and invert. "Life view" is also evolving.

m. WHAT IS NATURAL LIFE

Generally, in the human' consciousness, "True Life"refers to "Natural Life", especially human life. So, theproblem translates to "What is natural life".

Simply, "Natural Life" means "Natural Biology and theiractive process" on the earth nowadays. "Natural Biology"includes human, other animals, plants and microorganism.

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The main characteristics ofNatural Life are:* Natural growth, evolution, and not man-made.* Sexual reproduction, for example, human, other

animals and plants.* Based on protein, carbon-chain organic substance.* Having activity, include internal capability and

exterior behavior, especially intelligence and emotion, suchas human and other animals.

Although human think "Natural Life" is "True Life",there are a lot ofunclear problems. For example,A. "Origin "problem

Life originated from Biology, what did Biology originatefrom? Firstly, "Where did human come from?" If we sayhuman came from ape, "Where did ape come from?" ... till"Where did organic substance come from?" Nowadays,people think that organic substance came from inorganicsubstance, well then "How did they evolve?", "Under whatcondition did evolvement happen?"B. "Life-span"problem

What's the upper limit of human's life-span? Now,medical world thinks that the longest life-span of human is120 or 150, but someone in England lived 202 years. Howlong is human's life-span? Can human live for ever? Can weextend human's life with Artificial Life?C. "Sex"problemHow does the sex of biology--female and female arise?

How does lower biology with "sexual reproduction" evolveto biology with "asexual reproduction"? May the sex ofbiology, especially human be controlled beforehand?D. "Limit"problem

Is the limit between life and non-life, biology andnon-biology, organic substance and inorganic substance,Natural Life and Artificial Life absolute? Or may be relative?Some microorganism, such as bacteria and virus has neitherhigher Natural Life characteristics nor intellect and emotion.Maybe it is pre-life between life and non-life. Ismicroorganism true life?

E. "Intelligence" problemLife's pith is intelligence. But, how does intelligence form?

Does intelligence and Life come forth the same time? DoesNatural Life have intelligence? Human have intelligenceand animal have intelligence too. Such as many animals incircus can take in training and learning and perform variousintelligent complex actions. But do plants have intelligence?Sunflower can track the sun, does it have intelligence? Doesmicroorganism have intelligence? And germ and virus are sofurious and sly, do they have intelligence?F. "Emotion"problem

Life has abundant emotion. However, how does emotioncome into being? Are emotion and intelligence co-twin?Does Natural Life have emotion? Human have emotion,animals have emotion too. For example, a righteous dog

saves its host. Do plants have emotion? Do fellow-liketree and sensitive plant have emotion? This brings to mindone revolutionary romantic poem, "Life is dear, love isdearer. Both can be given up for freedom" Maybe, onlyhuman can realize the essence of Life, love and freedom.

IV. WHAT'S ARTIFICIAL LIFE

Normally, "Artificial Life" is "Man-made Life", not"Natural Life"From dreaming human' s forever living to studying

Artificial Life, human have undergone lengthy and flexuralexploring road. In Chinese typical fairy novel "apotheosishistorical novel", the story about nezha's lotus flowerreincarnation and rising again maybe the earliest sciencefiction on Artificial Intelligence in the world.

Latter-day Biological science and Engineering techniquestudy Artificial Life largely and have got plentiful outcome.Such as clone technology, heredity engineering, bionics,biomedicine engineering, biology cybernetics and ArtificialIntelligence. However, "Artificial Life" being a new subjectcame out only tens ofyears ago.On the span subject symposium of "Life system

emulation and synthesis" in America in 1987, C.Longton inSantaFe research institute published thesis named "ArtificialLife" and demonstrated Digital Life software based on cellautomaton in computer, represented the Natural Lifephenomenon and behavior of multiply, heredity andvariation. Scholars in the symposium agreed adopting newterm "Artificial Life" and named this symposium as the firstArtificial Life Technicality Meeting ALIFE-1. Thisindicated the naissance of "Artificial Life" new subject.The basic viewpoint of C.Langton on "Artificial Life" is

as follows:* Artificial Life is the study ofman-made system that

exhibit behaviors characteristic of natural living system.* Life is kind of behavior, not a kind of stuff. It is

the virtual parts of living systems that Artificial Life is after.* It complements the traditional biological science

concerned with the analysis of living organisms byattempting synthesize life-like behaviors with in computerand other artificial media.

* By extending the empirical foundation upon whichbiology is based beyond the carbon-chain life that hasevolved on Earth. Artificial Life can contribute thetheoretical biology by locating life-as-we-know-it with inthe larger picture of life-as-it-could-be.

It is obvious that the "Artificial Life" put forward byC.Langton has the following characteristics:

* Man-made system made in computer software andhardware technique.

* Artificial media(inorganic substance) based on noncarbon-chain.

* It can exhibit some life-like behaviorscharacteristics, such as multiply, inheritance and variation.

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* Artificial Life is simulation or expansion ofNaturalLife.

Since the concept of Artificial Life presented byC.Langton is only engineering technique system which hassome similar Natural Life characteristics and different fromNatural Life in our consciousness, people suspect that "IsArtificial Life true life?" In fact, they don't think that theabove "Artificial Life" is "true life".

V. GENERALIZED ARTIFICIAL LIFE

The first "Artificial Life and its Applications" symposiumwas held by CAAI in Beijing, 2002. Since we think that theconcept of "Artificial Life" presented by C.Langton hassome limitation, we put forward the concept of "GeneralizedArtificial Life".The main viewpoint of "Generalized Artificial Life" is as

follows:A.Purpose and content ofArtificial Life

Purpose and content of Artificial Life is prior to extendNatural Life, especially human life, such as study, develop,make use of artificial organs to cure the sickness to save thepatient and prolong life, not to limit to only simulate andextend Natural Life, such as digital life, robot noncarbon-chain engineering technique system. This is thepurpose and content ofhuman realistic and applied value.B.Artificial method and technique ofArtificial Life

Artificial method and technique of Artificial Life shouldadopt both synthesis and analysis, namely "analysis +synthesis" method. It can't only limit to engineeringtechnique, such as computer software, optics, machine andelectricity hardware technique, but also may adopt clonetechnique, gene engineering biological science techniqueand new method and new technique combined with biologyscience and engineering technique.C.Substance and material ofArtificial Life

Substance and material of Artificial Life not only limit tonon carbon-chain, non-protein inorganic substance, but alsouse organic substance based on carbon-chain, protein andcarbon-chain plus non carbon-chain, protein plus nonprotein inorganic substance plus organic substance.D. Characteristics and capability ofArtificial Life

The characteristics and capability of Artificial Life notonly limit to exhibit Natural Life exterior phenomenon andbehavior characteristics, but also has alike Natural Lifeinternal characteristics and configuration.

"Generalized Artificial Life" has the followingcharacteristics:

* Generalized object: simulate, extend and expandNatural Life, especially extend human life.

* Generalized method: Engineering scientifictechnique, Biological scientific technique and "Biology plusEngineering" scientific technique.

* Generalized stuff: inorganic substance, organicsubstance and "inorganic substance plus organic substance".

* Generalized characteristics: internal capabilitycharacteristics and exterior behavior characteristics.

Therefore, Generalized Artificial Life(GAL) is tosimulate, extend and expand natural life, especially humanlife. It is Generalized man-made life which adoptsanalysis(or/and) synthesis method and biology(or/and)engineering scientific technique, bases oncarbon-chain(or/and) non carbon-chain stuff and has alikeNatural Life internal capability and exterior behaviorcharacteristics.

Generalized Artificial Life(GAL) includes three offset:A.Biological Artificial Life

The characteristics of Biological AL (BAL) is based oncarbon-chain and protein organic stuff adopting biologicalscientific technique and has the same or alike configurationand capability behavior, internal and exterior characteristicsas Natural Life's. For example, clone sheep, transfer-genesuper mouse.B.Engineering Artificial Life

The characteristics of Engineering Artificial Life(EAL) isinorganic stuff adopting engineering scientific technique,based on non carbon-chain and non protein. It has somecapability or/and behavior characteristics alike Natural Life.For example, digital life, which is corresponding to theconcept of Artificial Life put forward by C.Langton, may becalled "narrow sense Artificial Life".C.Bio-Engineering Artificial LifeThe characteristics of Bio-Engineering AL(BEAL) is that

it is based on carbon-chain and non carbon-chain, proteinand non protein organic and inorganic stuff adopting thecombination of biology science and engineering technique.It has alike Natural Life configuration and capabilitybehavior. For example, human with artificial organ is calledCyborg.

Although human suspect or don't think "EngineeringArtificial Life" is "true life", but they shouldn't suspect"Biology Life" and "Bio-engineering Artificial Life" is"True Life".

VI. CONCLUSIONS

According to above "Is Artificial Life True Life?"discussion, the basic viewpoint is as follows:

l)Life means active substance and its activity. Lifeoriginated from biology, Life bases on substance, Lifeindwells system, Life is controlled by information, Life'spith is intelligence and Life is abundant in emotion.

2)Natural life means known biology on the earth, whichincludes human, other animals and plants. This is "TrueLife" of human consciousness. Microorganism may bepre-life between life and non-life. Whether they are true lifeis still in discussion.

3) Artificial Life means man-made life, non-natural life.

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The concept of "Artificial Life" presented by C.Longton hassome limitations. It is "narrow sense Artificial Life", namely"Engineering Artificial Life". Nowadays, people think that itis not true life.

4) "Generalized Artificial Life" means GeneralizedArtificial Life, which includes "Biology Artificial Life,Engineering Artificial Life(narrow sense Artificial Life) andBio-Engineering Artificial Life. Therein, "Biology ArtificialLife" and "Bio-Engineering Artificial Life" should be "TrueLife".

REFERENCES

[1] Tu Xuyan, Huang Bingxian, Guo Rongjiang, Pan hua. "BiologyCybernetics", Science Publishing House,1980

[2] Tu Xuyan, "Artificial Intelligence and its Application", Electronic

Industry Publishing House, 1988[3] Tu Xuyan. "Artificial Intelligenceand Artificial Life", proceedings of Chinese Intelligent Automation,2000

[4] Tu Xuyan, "Generalized Artificial Intelligence', China ArtificialIntelligence Progress, Beijing University of Posts andTelecommunications Publishing House, 2001

[5] Tu Xuyan. "Generalized Artificial Life and its Application",proceedings of the First CAAI Workshop on "Artificial Life and itsApplication", 2002

[6] Tu Xuyan, "Artificial Emotion", China Artificial Intelligence Progress,Beijing University of Posts and Telecommunications PublishingHouse, 2001

[7] Tu Xuyan, "Generalized Artificial Life Research, Development andApplication", China Artificial Intelligence Progress, BeijingUniversity ofPosts and Telecommunications Publishing House, 2004

[8] C.Lang.ton, "Artificial Life", ALIFE-1 (An Interdisciplinary Workshopon the Synthesis and Simulation ofLiving Systems), 1987

[9] Tu Xuyan, Generalized Artificial Life Race and Model, InternationalSymposium on AROB-8,2003

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