  For now, let us assume that there is a way of characterizing fitness such that there is a substantial empirical question of what role indiscriminate sampling of genotypes (or phenotypes) plays in evolutionary change.  This issue was first placed squarely before evolutionary biologists by Sewall Wright in the early 1930s. As Wright pointed out, genes that are neutral with respect to fitness can, due to the stochastic nature of any process of sampling from a population, increase their representation from one generation to the next. The likelihood of this happening goes up as effective population size goes down. Since Wright imagined that a quite typical scenario in evolutionary change was for species to be broken up into relatively small, relatively isolated, populations (or ‘demes’), with significantly more breeding within than between demes, the likelihood that such ‘neutral genotypes’ could become fixed at relatively high levels was significant. Though he gradually toned down this aspect of his work, a significant school of mathematical population geneticists in the 1960s and 70s took these ideas and ran with them, developing a ‘Neutralist’ approach to evolutionary change.  This is the position characterized by Kimura (one of its most eloquent defenders) in the passage quoted above. Whether or not such a process plays a significant role in evolution is not a philosophical issue, but it is highly relevant to whether evolutionary biology should be seen as predominantly Darwinian. For if any view is central to Darwinism, it is that the evolutionary process is predominantly guided by the fitness-biasing force of natural selection, acting on variations that arise by chance. It is to natural selection and related concepts that we now turn.