Artificial life (commonly Alife or alife) is a field of study and an associated art form which examine systems related to life, its processes, and its evolution through simulations using computer models, robotics, and biochemistry. There are three main kinds of alife, named for their approaches: soft, from software; hard, from hardware; and wet, from biochemistry. Artificial life imitates traditional biology by trying to recreate biological phenomena. The term "artificial life" is often used to specifically refer to soft alife.
Artificial life studies the logic of living systems
in artificial environments. The goal is to study the phenomena of living systems in order to come to an understanding of the complex information processing that defines such systems.
Also sometimes included in the umbrella term Artificial Life are agent based systems which are used to study the emergent properties of societies of agents.
At present, the commonly accepted definition of life
does not consider any current alife simulations and softwares
to be alive, and they do not constitute part of the evolutionary process of any ecosystem
. However, different opinions about artificial life's potential have arisen:
- The strong alife (cf. Strong AI) position states that "life is a process which can be abstracted away from any particular medium" (John von Neumann). Notably, Tom Ray declared that his program Tierra is not simulating life in a computer but synthesizing it.
- The weak alife position denies the possibility of generating a "living process" outside of a chemical solution. Its researchers try instead to simulate life processes to understand the underlying mechanics of biological phenomena.
- Cellular automata were used in the early days of artificial life, and they are still often used for ease of scalability and parallelization. Alife and cellular automata share a closely tied history.
- Neural networks are sometimes used to model the brain of an agent. Although traditionally more of an artificial intelligence technique, neural nets can be important for simulating population dynamics of organisms that can learn. The symbiosis between learning and evolution is central to theories about the development of instincts in organisms with higher neurological complexity, as in, for instance, the Baldwin effect.
Evolutionary art uses techniques and methods from artificial life to create new forms of art.
Evolutionary music uses similar techniques, but applied to music instead of visual art.
- Artificial intelligence has traditionally used a top down approach, while alife generally works from the bottom up.
- Artificial chemistry started as a method within the alife community to abstract the processes of chemical reactions.
- Evolutionary algorithms are a practical application of the weak alife principle applied to optimization problems. Many optimization algorithms have been crafted which borrow from or closely mirror alife techniques. The primary difference lies in explicitly defining the fitness of an agent by its ability to solve a problem, instead of its ability to find food, reproduce, or avoid death. The following is a list of evolutionary algorithms closely related to and used in alife:
Alife has had a controversial history. John Maynard Smith
criticized certain artificial life work in 1994
as "fact-free science". However, the recent publication of artificial life articles in widely read journals such as Science
is evidence that artificial life techniques are becoming more accepted in the mainstream, at least as a method of studying evolution