Life as we know it", or the life we are very familiar with, appears to be composed of highly complex structures capable of reproduction and evolution and of interacting with their environment in order to maintain their own integrity (at least, up to a point). So far, it appears that these organisms are solely based on complex chemical structures. Although it cannot be ruled out that perhaps mineral, plasma or even nuclear-based architectures for life by this definition may be possible, it is not certain that these templates can generate the required complexity.

Our own experience with complex machines suggests that artificial structures with the characteristics of life are almost certainly probable, either constructed as mechanical artifacts, or virtually as self replicating and evolving algorithms or celullar automata. This is not necessarily a technological phenomenon--some large administrative entities seem to exhibit the properties of living things, it can be argued that governments and corporations often exhibit behavior totally separate from the wishes and desires of the human intelligences which compose their component parts. They seem to have a life of their own, those who believe human institutions are under human control are only misleading themselves. For that matter, languages evolve, survive, affect their human environments, fuse (sex) and fission (reproduce), are they alive? Does English represent the combined genetic materials of the Romance and Germanic languages? And do those language families represent a branch in the evolution of an Indo-European root tongue?

The question then arises, is artificial life "real", since it is the result of deliberate design and construction by an existing biological intelligence? Or should the term "life" be reserved for those beings which arise from purely stochastic and undirected processes. As certain religions remind us, clocks abound on earth, but they arise only from human activities and not from natural processes. This again suggests that some levels of complexity cannot be achieved through non-directed processes, but require a pre-existing biological organism to generate them. This is not a function of complexity, clocks are simpler than proteins, but the latter can arise from purely chemical processes, the former require a workshop and a craftsman. Perhaps evolution is God's way of making clocks, he can't make them them Himself, but we can!

By my definition, any complex structure which interacts with its environment and at least temporarily maintains its own integrity can be considered alive. Evolution and reproduction may not be requirements, but they help us to identify these structure/processes. The Galaxy itself exhibits all these characteristics, is it alive?

Without invoking supernatural explanations, there appears to be a tendency in the universe to create complex structures, usually at the expense of less complex structures about them. Energy flows from concentrated to dispersed forms, and as it does so it creates pockets of organization. This is entropy, and like a flowing river, the disintegration of the overall general complexity of the universe forms temporary eddies and whirlpools of local high complexity which tend to speed the entire process along, indeed, may be essential to it. An enormous amount of hydrogen has to fuse to helium in the sun's core so a few photons will become available to nourish a humble plant, which in turn breaks down minerals and nutrients in the soil to create a highly complex living thing. The net result is a drop in total complexity, but the plant itself is much more complex than the hydrogen plasma and mineral structures it replaces.

Perhaps the evolution of intelligent biological life is only the first step, a necessary step required to create highly complex artificial life. When viewed in terms of entropy and energy flow, this process is simply an inevitable property of the universe itself, hard-wired into it at the beginning when the laws of physics were created and understandable in terms of the simplest physical law. I cannot believe God created a universe he needed to constantly fiddle with to keep it running efficiently. He created it right the first time, self maintaining and self governing. Then He just walked away.