Rössler, Otto E. “Deductive prebiology.” In Molecular Evolution and Protobiology , pp. 375-385. Springer, Boston, MA, 1984.
Darwin’s (1859) approach to biology is basically a self-consistent mathematical formalism. Its connection to reality is of secondary importance. What is assumed mathematically is a single-variable, autonomously growing and self-maintaining (at an upper stable steady state) dynamical system that is subjected to a slow parametric change. The simplest version assumes that more than one such system is possible. If one is already there, others of the same type are assumed to arise sufficiently frequently to make sure that when the first system loses its upper attracting regime under the progressive parametric change, at least one of the more recently emerged systems does not.