The Baldwin Effect and the Potentialities for Thoughtful Darwinism around 1900

For anyone concerned with biology, 1900 marks the year when three researchers independently converged on the patterns and explanations of the long-dead Mendel. So began the science we know as genetics. Less well remembered is another triple convergence a little earlier, 1896, on what’s become known as the “Baldwin effect,” named after one of its co-discoverers, the American psychologist James Mark Baldwin. The idea of the Baldwin effect is that after an environmental change, animals acquire new adaptive habits, and eventually those habits get replaced by hereditary variations preserved by natural selection. As clues to the energies animating the era’s biological debates, the Mendelian triple and the Baldwinian triple are as different as could be. This chapter expands the frame around the Baldwinian triple to exhibit the creative resourcefulness of Darwinian discussion in the 1890s and 1900s—a thoughtful discussion both in its recognition of complexity and its concern with “mental factors” in evolution, not least agency. Particular topics covered include the following: the post-Lamarckian debate over mental evolution, the post-Morgan’s-canon debate over female choice in sexual selection, E. Ray Lankester’s Darwinian case for the rise of “educability,” and W. F. R. Weldon’s Darwinian dissolution of the notion of an “acquired character.”