Commentary — Reading the latest investigations on whether life exists on Mars and on nanobacteria can reasonably sprout one question: What is life, anyway? And reading the Wiki entry on what life is can only sprout more questions.
In biology, an entity has traditionally been considered to be alive if it exhibits all the following phenomena at least once during its existence:
- Metabolism, consuming, transforming and storing energy/mass; growing by absorbing and reorganizing mass; excreting waste
- Motion, either moving itself, or having internal motion
- Reproduction, the ability to create entities that are similar to itself
- Response to stimuli
- The ability to measure properties of its surrounding environment, and act upon certain conditions
According to this definition, a fire is alive. But a mule isn’t. Nor is a virus or a nanobacteria.
If a virus is alive, I would personally suggest that, to a certain extent, so is much about anything that involves chemical reactions. So-called “inanimate” matter included; that matter is inanimate is only a question of time-space reference as far as I can tell. Thus, much about everything on Earth would be alive. Agreed; this sounds like some weird version of the Gaia theory. But then, given that individuals such as you or I are merely a bunch of cells working together and that our respective consciouses are the result of chemical activity within these cells, who can tell whether or not there is a so-to-speak Earth-level semi-conscious that results from all the chemical activity on it? Just a random thought…
Anyway, our interest here would mostly be genetic algorithms and other kinds of mutating algorithms. Are these things alive? Suppose you make an artificial intelligence that achieves a clear state of consciousness. Is it alive?