Commentaries on Viewpoint: Emergent phenomena and the secrets of life

摘要

TO THE EDITOR: Peter Macklem (1) makes important points relating to life most cogently. What we observe on the surface of the earth is most decidedly not what we might immediately predict from the Second Law of Thermodynamics, and this arises only through the constant supply of energy. In a sense, however, this is a permissive explanation-it says that we may observe ordered systems, but not necessarily that we should. Why should we observe ordered systems? At the heart of this lies an asymmetry. On the one hand, disordered configurations are much more likely than ordered configurations, but because of their very nature (disordered) they cannot replicate. On the other hand, rare ordered configurations have the potential through their very nature (ordered) to self-replicate, It is this asymmetry that allows imposition of order onto disorder and that generates the phenomena that we observe on earth. Within his article, Peter Macklem (1) describes autocatalytic sets in peptide chemistry as examples of such systems that have been generated in the laboratory. We lack, however, a more abstract understanding of the process. Questions include what sorts of objects and interactions have to be present for self-replicating systems to develop; how big do such sets have to be; how long do interactions have to run; and, so important to life, how do hierarchical layers of self-replicating systems develop? In this sense, life should be seen as the remarkable result of some physical law concerning a fundamental asymmetry between order and disorder.