Exobiology, the field that hunts for alien life, is a science without a
subject matter. This makes difficult the use of "the" scientific method
in the hunt. Tools used routinely to detect life on Earth are not likely
to detect alien life. Nothing illustrates this better than recent
exploration of Mars. Metabolism-like reactions, carbon fixation, oxygen
release, perchlorate and (just last week) methane have all been observed
on Mars. All might be considered to be signs of life, but might also
arise without biology.
Needed, but missing in exobiology, is a "theory" of life, an overarching
framework that connects chemistry, information, and physiology to
Darwinian processes, which are believed to be the only way that matter
can spontaneously organize itself to give the attributes of life. A
theory of life as a universal "natural kind" must come indirectly, as
"universal life" cannot be observed directly.
This talk will feature recent efforts to build a general theory, efforts
that include the resurrection of ancient forms of life for study in the
laboratory, the combination of geology and chemistry to understand
life's origins, and the construction of artificial chemical systems
capable of Darwinian evolution in a "synthetic biology."