The rise of scientific psychology coincided with the acceptance of evolutionary theories into mainstream science. Just as sensation, cognition and behaviour came to be studied as organic functions, the very concept of an organic function took on a radically historical dimension. As a result, evolutionists were now claiming that mental processes derive from a nervous system that had developed over millennia to manage the concrete exigencies of life. Mind was no longer an exalted faculty of knowledge but a set of instrumental functions tethered to an environment that had slowly ground them out. Nineteenth-century evolutionism does not speak with one voice, however. The competing mechanisms of natural selection and the inheritance of acquired characteristics, for instance, suggest different relationships between ontogeny and phylogeny – individual development and the history of species – and each mechanism has been subject to competing interpretations that emphasize different internal and environmental factors. Tracing the influence of evolutionism in psychology therefore requires attending to the specific logics of particular evolutionary theories. The present chapter does not attempt to map out this entire territory but instead traces one instructive path: that of William James. James was among the most influential psychologists in the decades following the publication of Darwin’s On the Origin of Species (1859), especially in the US. Known as the Father of Amer ican Psychology, James is credited with founding the first psychology laboratory in the US in 1875;1 teaching the first physiological psychology course in the US in the same year; supervising the country’s first PhD in psychology in 1878; and publishing the seminal text of early US psychology, The Principles of Psychology, in 1890. An examination of James’s scientific education and early writings show how he understood Darwinism to be emblematic of the uncertainty of science. James nevertheless embraced Darwin’s theory, not just in explaining mental evolution, but also in modelling individual cognition and behaviour. James thus employs selectionist logics at both phylogenetic and ontogenetic levels, making him the first double-barrelled Darwinian psychologist. This chapter outlines the sources of James’s Darwinism in his education and early publications, before investigating his shift to an overtly Darwinian and

anti-Lamarckian position in The Principles of Psychology. This investigation unearths an interesting interpretive tension. On the one hand, James presages neo-Darwinism in his physiological approach to mental life, his early repudiation of the inheritance of acquired characteristics and his creative extensions of Darwinian logic to non-biological domains. On the other hand, the twin lessons of Darwinian psychology for James are, first, that both science and philosophy are open-ended processes of fallible, inductive guesswork; and second, that the individual as such is a real locus of agency in the world. Darwinism for James signals a world that is both theoretically and actually in the making, with the individual as an active participant.