The Conditions of Natural Selection and Evolutionary Definitions of Life

Abstract

The aim of this paper is to provide an analysis which connects the discussion
about the definition of life with the discussion about the requirements for evolution
by natural selection. One of the most popular definitions of life is the so-called
Darwinian definition, according to which “life is a self-sustained chemical system
capable of undergoing Darwinian evolution” (Joyce 1994: xi). It is an example of a
broader family of evolutionary definitions. The problem of defining life causes a lot
of controversy. Still, the fundamental requirements for natural selection are also a
subject of discussion. This implies that different formulations of basic conditions for
natural selection are relevant for defining life. In other words, a given formulation of
basic conditions for selection will result in a different classification of phenomena
(as living or not) by the Darwinian or other evolutionary definition. The basic conditions
for selection can also be important for some operational and other methodological
aspects of the definition of life.
In this paper, I analyse the classical approach to natural selection (represented by
Lewontin, Endler, and Maynard Smith), the replicator-interactor framework for
selection (put forward by Dawkins and Hull), and “non-classical” approaches for
selection (represented by Bourrat, Bouchard, and Gecow). Godfrey-Smith’s “antiessentialist”
conception of Darwinian space is also taken into account. Finally, I argue
that although Bourrat’s approach seems to have very interesting implications for
defining life, it cannot (at this stage) replace the classical formulation as the best
basis for the Darwinian definition of life.
Keywords: natural selection, classical requirements for natural selection, replicator-
interactor conception of natural selection, non-classical (non-standard) approach
to natural selection, definition of life, evolutionary definition of life, Darwinian definition
of life, philosophy of biology