Other Forms of Life (Evolution)

by dhw, Monday, March 15, 2010, 17:32 (5163 days ago) @ dhw

There is a fascinating article by Paul Davies in today's Guardian, concerning the search for alien life. It's too long to quote in full, and I can't find a link, so I will quote the most salient section:-"The problem is that even the simplest living thing is already so stupendously complex that if such an entity were to be thrown together by chance, it would be a fluke of such magnitude as to be unlikely to happen twice in the observable universe, vast though that may be.-However, we don't know that life's origin was purely a chemical accident. Scientists are aware of all manner of self-organising processes that might have fast-tracked mindless molecules down a path of complexification leading to life. Indeed, that is the fashionable view. The biologist Christian de Duve expresses it splendidly with the evocative slogan that "life is a cosmic imperative".
 
Unfortunately, there are few grounds for this new-found optimism. Scientists have no agreed theory of the origin of life ... plenty of scenarios, conjectures and just-so stories, but nothing with solid experimental support. Life may emerge from unremarkable chemical sludge with a high degree of probability; but then again, it may not. We haven't a clue either way. And while we are completely in the dark about precisely what it takes for life to start up, putting an estimate on the numbers of alien civilizations is pointless.-There might be a way to solve this problem at a stroke. No planet is more earth-like than Earth itself, so if life really does pop up readily in earth-like conditions, then surely it should have arisen many times right here on our home planet? And how do we know it didn't? The truth is, nobody has looked."-He goes on to say that a few scientists are now actively looking for forms of life on Earth that are different from those we know. If such forms were found, they would indicate a second genesis, and this in turn would make it "fairly certain" that there is life elsewhere. "And once life gets going, there is at least a chance that intelligence will evolve."-If other forms of life are found, proponents of design can still argue that God would not have confined himself to a single experiment; if other forms are not found, proponents of chance can still argue that we should keep looking, or that this uniqueness shows just how incredibly lucky we are. All the same, the discovery of other forms would add a new dimension to the discussion. Until then, the fact that "we haven't a clue" serves only to highlight the degree of faith required by those who think they do have a clue.-*** Postscript: you can find the full article and comments on
http://www.guardian.co.uk/commentisfree/2010/mar/14/life-aliens-planet-second-genesis