Our journal club on Thursday was presented by my new PhD student, Ernest Liu, about a relatively old (1999) paper on the Evolution of Biological Complexity. The authors study what happens when computer programs are forced to compete for access to CPU time and memory. Those programs that work most effectively are able to reproduce and natural selection does its stuff, the fittest programs survive. The framework for these simulations is called Avida has now been around for 20 years.
The paper itself addresses a really fundamental problem in biology: why are there all these complex living forms around us? The answer the authors suggest is that natural selection acts to reduce randomness and make things which are more structured. There is a lot of technical discussion of how to measure randomness and how to define complexity (they define complexity=genome length-genome entropy), but this is the basic result. Natural selection will make genomes less random.
Naturally, the biologists amongst us were not exactly impressed with this revelation. That natural selection eliminates randomness is more or less true by definition. But there are a few additional insights gained in studying evolution of computer programs. For example, there are sudden fitness jumps in the computer simulations, accompanied by decreases in genome randomness. These are reminiscent of 'biological' evolution and are reproduced in the 'artificial' evolution in Avida.
This leads me to my title 'Is Artificial Life still alive?'. It seems to me that research progress since this paper has been pretty slow. Yes, there are Artificial Life conferences and a society with a journal, but the work I have read here is more concerned with engineering challenges and less concerned with the fundamental questions in biology. One nice recent exception to this trend is a paper by Philip Gerlee and Torbjörn Lundh on cross feeding artificial organisms.
One of the reasons for the failure of Aritificial Life to take off in serious biology research is reflected in the reaction of the biologists in our journal club when they read the paper. This research too often looks like Darwin needlessly translated into 'Entroponeese' or some other obscure mathematical language, without providing any new insight. I still think there is potential here, and Philip and Torbjörns' work reflects this potential. I'm interested to hear if anyone else knows of any other signs of life in Artificial Life.