What’s Natural About Natural Selection?

As Darwin originally conceived it, natural selection not only chose features that, in retrospect, would allow those with them to be better adapted to their immediate circumstances—it was also the agent provocateur of the pool of variation from which it chose these better-adapted features. Gradually, over immense amounts of time, the accumulation of these “infinitesimally small” adaptive changes would yield a new species. After Morgan successfully substituted gene mutation for natural selection as the basis of morphological change, for many evolutionists (but not those following in the intellectual footsteps of Darwin’s contemporary saltationists Mivart, Huxley, and Galton) natural selection remained the guiding “force” that, by choosing from among available variants, continually reshaped features and, thus ultimately, species. The late twentieth century-to-present language of evolution has retained the notion of natural selection having the power to provoke change, even at the genetic level. Here I review the history of these and alternative, non-Darwinian ideas—focusing on the inclusion as well as absence of development and developmental thinking especially in terms of conceptions of heredity and species formation—and point out how much of what is assumed to be true of evolution by means of natural selection remains assumption and suggest that it is time to re-evaluate the utility of invoking selection to explain evolutionary phenomena.