Wednesday, September 16, 2015

Not-So-Simple Origins (or The Fortuitous Labyrinth Ball Game)

From "A Simpler Origin of Life" by Robert Shapiro (emphases mine):

The [speculated] exceptionally high urea concentration was rationalized in the Nature paper by invoking a vision of drying lagoons on the early Earth. In a published rebuttal, I calculated that a large lagoon would have to be evaporated to the size of a puddle, without loss of its contents, to achieve that concentration. No such feature exists on Earth today. 
The drying lagoon claim is not unique. In a similar spirit, other prebiotic chemists have invoked freezing glacial lakes, mountainside freshwater ponds, flowing streams, beaches, dry deserts, volcanic aquifers and the entire global ocean (frozen or warm as needed) to support their requirement that the "nucleotide soup" necessary for RNA synthesis would somehow have come into existence on the early Earth. 

The analogy that comes to mind is that of a golfer, who having played a golf ball through an 18-hole course, then assumed that the ball could also play itself around the course in his absence. He had demonstrated the possibility of the event; it was only necessary to presume that some combination of natural forces (earthquakes, winds, tornadoes and floods, for example) could produce the same result, given enough time. No physical law need be broken for spontaneous RNA formation to happen, but the chances against it are so immense, that the suggestion implies that the non-living world had an innate desire to generate RNA. The majority of origin-of-life scientists who still support the RNA-first theory either accept this concept (implicitly, if not explicitly) or feel that the immensely unfavorable odds were simply overcome by good luck.
 But this is what all evolutionary plausibility arguments invoke.  We are here, so evolution happened.  So whatever unlikely natural event  needed to occur to make it happen must have happened.

To say that the events invoked must be a priori not ridiculously unlikely is to threaten the whole edifice of evolution.  Unless, of course, the self-organization people are able to pull a rabbit out of their hat with concrete results on origin of life (not just interesting ideas).

Think of a labyrinth ball game (pictured).  The ball can always get from start to finish without any intelligent maneuvering, as long as the right fortuitous conditions occur (ground vibrations, air gusts, etc.).  In fact there are innumerable such scenarios that can account for the ball getting from start to finish on its own.  They are so outweighed by the far more innumerable ways that the ball never gets there.

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