Sara Imari Walker: Stuart Kauffman provocatively concludes, there is no mathematical law that could describe the evolving diversity and abundance of life in the biosphere. He writes: “we do not know the relevant variables prior to their emergence in evolution.” At best, he argues, any ‘laws of life’ that do exist will describe statistical distributions of aspects of that evolution. For instance, they might predict the distribution of extinctions. Life’s emergence might rest on the foundations of physics, “but it is not derivable from them,” Kauffman argues.