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What is artificial life?
Artificial Life, "is a field of study devoted to understanding life by attempting to abstract the fundamental dynamical principles underlying biological phenomena, and recreating these dynamics in other physical media, such as computers, making them accessible to new kinds of experimental manipulation and testing." (Chris Langton, 1992). The underlying principle of the artificial life, from this description, is the recreation of autonomous organic style entities in an artificial world.
The field of study of Artificial Life not confined to computer science it draws from many different disciplines such as anthropology, physics, genetics, biology, chemistry, philosophy, etc. Each of the disciplines combines to allow an effective recreation of the organic entities.
Moshe Sipper uses a simple but effective description of "Life-As-It-Could-Be"(M. Sipper, 1995), this gives highlights the basics of the artificial life, Alife, principles. The discipline is concerned with more than just the recreation of simple imitations of organic interaction. Could we simulate fish swimming in a virtual fish-tank? This may be a small yet insignificant, aspect of Alife studies as it is part of the wider field of interaction of multiple simulated organic objects. An example of this type of work you will have seen in many Hollywood movies, flocking birds, bats and even dinosaurs.
C. Reynolds worked on a flocking behaviour simulator in order to gain a better understanding of the dynamics of the group structure. Reynolds began to investigate how flocks of birds fly, without central direction or a clearly dominant individual. The result of his work is a virtual bird called a "boid", these boids conform to three basic rules;
- Collision Avoidance: Must avoid colliding with other objects.
- Velocity Matching: Attempt to match velocity with nearby boids.
- Flock Centring: Attempt to stay close to nearby flock-mates.
When Reynolds' virtual world was populated with boids, they began to instantly display flocking tendencies flying in a cohesive group. When obstacles appeared in their way they spontaneously split into two subgroups, without any central guidance, rejoining again after clearing the obstruction.
This may seem only to serve as an example of cleaver programming, but the model does exhibit the basic principles of Alife. A number of simple objects interacting with each other in an artificial environment without a central controlling entity. " Although Reynolds' boids are artificial, the flocking behavior is as real as that observed in nature." (M. Sipper, 1995)
Another question that Alife is attempting to supply an answer too is the one posed by John von Neumann in the early 1950s; "Can machine reproduce?" T.S. Ray addressed the initial question by researching a different question; "Can open-ended evolution be constructed within a computer?" (T.S. Ray, 1992)
Ray devised a virtual world that consisted of genetic programs that were able to 'evolve'. This virtual world is known as "Tierra". The research was to discover how the entities would develop with human assistance or guidance. Unlike standard genetic programming no 'fitness' aspect was written into the algorithms. The limiting factor in the evolutionary battles would be the resources available within the virtual environment, i.e. the CPU time and memory.
Ray seeded his virtual world with a single self-replicating creature; he called the "Ancestor". The results were astonishing, as an entire ecosystem has been formed in the Tierra world, including organisms of various sizes, parasites, etc. The parasites that had evolved are small creatures that use the replication code of larger organisms (such as the ancestor) to self-replicate. Ray's current research is looking at the possible results that could be attained if the virtual environment was widened. Imagine what could be possible if the computing power of the Internet was harnessed as part of this virtual world?
Why is Alife exciting and how could it be useful? It has created the possibility of designing and conducting dedicated experiments with that without such systems that could never be performed. If we are able to understand the interactions of the of low leave entities, in the case self-replicating, we could evolve truly unique and powerful applications. The problems could be far to complex for any human mind to comprehend, even at the highest level. I am not suggesting that machines would necessarily be able build other machines that exist is our physical world.
The biochemical and pharmaceutical industries could test the interactions and reactions to new drugs on organic creatures via these synthetic worlds. The way that the Alife can mimic the physical organic world may result in a better understanding as to the causes of many presently incurable diseases. How does cancer form and how can we stop its spread? At present we must destroy life in order to study it, which obviously does not lead to a clear understanding. The better we can simulate these organic interaction the less the need to dissect living organisms.
C. G. Langton. (1992) "Preface." - C. G. Langton, C. Taylor, J. D. Farmer, and S. Rasmussen, editors - "Artificial Life II", volume X of SFI Studies in the Sciences of Complexity, pages xiii-xviii, Redwood City, CA, 1992. Addison-Wesley.
M. Sipper (1995) - "An Introduction to Artificial Life" Explorations in Artificial Life (special issue of AI Expert), pages 4-8, Sept 1995.
T. S. Ray. (1992) "An approach to the synthesis of life." - C. G. Langton, C. Taylor, J. D. Farmer, and S. Rasmussen, editors - "Artificial Life II", volume X of SFI Studies in the Sciences of Complexity, pages 371-408, Redwood City, CA, 1992. Addison-Wesley.