Paul Davies, who wrote The Fifth Miracle, on life in the universe:-"The underlying problem is complexity. Even the simplest bacterium is, at the molecular level, staggeringly complex. Although we have no idea of the minimal complexity of a living organism, it is likely to be very high. It could be that some sort of complexifying principle operates in nature, serving to drive a chaotic mix of chemicals on a fast track to a primitive microbe. If so, no hint of such a principle has been found in laboratory experiments to re-create the basic building blocks of life." -http://www.nytimes.com/2013/11/19/opinion/are-we-alone-in-the-universe.html?nl=todaysheadlines&emc=edit_th_20131119&_r=0