The only complete part of this FAQ is the introductory section, which contains answers to some commonly asked questions. These are available on the FTP server rtfm.mit.edu, as well as many other FTP servers. Tom Ray's Tierra.
Biology is the scientific study of life - in principle, anyway.
In practice, biology is the scientific study of life on Earth based on carbon-chain chemistry. Thus, theoretical biology has long faced the fundamental obstacle that it is impossible to derive general principles from single examples. In order to derive general theories about life, we need an ensemble of instances to generalize over. Alife complements the traditional analytic approach of traditional biology with a synthetic approach in which, rather than studying biological phenomena by taking apart living organisms to see how they work, one attempts to put together systems that behave like living organisms. The process of synthesis has been an extremely important tool in many disciplines.