Making the Jump from Prelife to Life: The Enigma Remains

The American Chemical Society's special issue of Accounts of Chemical Research is dedicated to chemical evolution. See our previous comments here and here. Now let's look at an article by Irene Chen and Martin Nowak that addresses the fundamental evolutionary step involved in making the transition from non-life to life ("From Prelife to Life: How Chemical Kinetics Become Evolutionary Dynamics"). The authors say that they are going to explain how longer RNA sequences arise from shorter ones and how the ability to replicate emerges.
OK, let's hear it.
Well, the article proposes a model based on prior origin-of-life research. Thus the authors assume that certain research questions are already answered. Many of their assumptions are, however, problem areas for RNA-world experiments.
The model on offer is based on chemical kinetics (reaction rates) giving rise to evolutionary dynamics (replication and competition). Essentially, the authors define "prelife" as a system that maintains chemical rules and "life" as a system that maintains biological rules. Prelife systems are subject to chemical equilibrium and reaction rates. Living systems are subject to environmental pressures and replication rates. Therefore, the point at which a chemical system can self-replicate is the point at which the system transitions from prelife to life. Here is how the authors define this distinction:
Prelife is characterized by gentle changes in the abundance of different sequences in response to differences in reactivity. Such a response of the system would be familiar to those who study chemical systems. On the other hand, if the polymers are able to template and thereby self-replicate, the dynamics change abruptly, and the fittest sequences dominate the pool in large excess even if they are only slightly better replicators than the rest. And if two systems compete for resources, one can exclude the other. Such features would be familiar to those who study biological systems.
Implicit here is the assumption that biological and chemical systems operate differently. But the authors explicitly compare their model to a bottom-up approach to synthetic life. Usually when people take a "bottom-up" approach, they are assuming that biology is reducible to chemistry. Otherwise it is NOT a "bottom-up" approach, but is based on some other overarching parameter or driving force.
Here is a summary of the proposed model: