No definition of life works. So life doesn’t really exist.
|December 3, 2013||Posted by News under Origin Of Life, News|
Life doesn’t really exist? In a thought-provoking piece in Scientific American, Ferris Jabr mulls over the fact that we don’t really have a definition of life that works well in all cases, and ends up concluding that life is just a continuum from non-life and doesn’t really exist as a separate catgory:
If we could somehow see the underlying reality of our planet—to comprehend its structure on every scale simultaneously, from the microscopic to the macroscopic—we would see the world in innumerable grains of sand, a giant quivering sphere of atoms. Just as one can mold thousands of practically identical grains of sand on a beach into castles, mermaids or whatever one can imagine, the innumerable atoms that make up everything on the planet continually congregate and disassemble themselves, creating a ceaselessly shifting kaleidoscope of matter. Some of those flocks of particles would be what we have named mountains, oceans and clouds; others trees, fish and birds. Some would be relatively inert; others would be changing at inconceivable speed in bafflingly complex ways. Some would be roller coasters and others cats.
An alternative possibility is that we need to bring information into the picture to understand life, but for understandable reasons, the Scientific American maven would not want to go there (it raises issues around probability and design and stuff).
One thing he reports that is quite interesting is how NASA ended up with a definition of life: a self-sustaining system capable of undergoing Darwinian evolution. It seems obviously wrong at the outset because Darwinian evolution was a theory developed to explain how life forms change over time. It would be, if correct, a characteristic of life, not its defining quality. Well, it seems,
In the early 1990s, Gerald Joyce of the Scripps Research Institute was a member of an advisory panel to John Rummel, manager of NASA’s exobiology program at the time. During discussions about how best to find life on other worlds, Joyce and his fellow panelists came up with a widely cited working definition of life: a self-sustaining system capable of Darwinian evolution. It’s lucid, concise and comprehensive. But does it work?
By this definition, Joyce says, viruses are not life forms. Despite pandoravirus, which is shaking the tree of life. Besides which, …
Defining life as a self-sustaining system capable of Darwinian evolution also forces us to admit that certain computer programs are alive. Genetic algorithms, for instance, imitate natural selection to arrive at the optimal solution to a problem: they are bit arrays that code traits, evolve, compete with one another to reproduce and even exchange information. Similarly, software platforms like Avida create “digital organisms” that “are made up of digital bits that can mutate in much the same way DNA mutates.” In other words they, too, evolve. “Avida is not a simulation of evolution; it is an instance of it,” Robert Pennock of Michigan State University told Carl Zimmer in Discover. “All the core parts of the Darwinian process are there. These things replicate, they mutate, they are competing with one another. The very process of natural selection is happening there. If that’s central to the definition of life, then these things count.”
Okay, so how did NASA end up with this bucket of cement of a definition?:
The working definition was really just a linguistic convenience. “We were trying to help NASA find extraterrestrial life,” he says. “We couldn’t use the word ‘life’ in every paragraph and not define it.”
Bureaucracy. Bureaucracy won. 😉