This textbook marked an important transition from mental philosophy to scientific psychology and from a narrow focus on the structure of consciousness to the psychological study of the purpose and processes of human functioning. At the time of its publication in 1890, the idea from associationistic philosophy that complex thought results from the mechanical compounding of correlated sensations was still the prevailing assumption of experimental psychologists. These psychologists used their own introspections to attempt the dissection of conscious experience into its elements.
William James was influenced by strands of thought outside this tradition. Influencing James’s psychological viewpoint were naturalist Charles Darwin and his ideas about adaptive evolutionary change, philosophical pragmatism with its notion that all theories should be judged by their practical usefulness, and a scattering of German psychologists, called “act psychologists,” who viewed psychology as the study of psychological processes. James therefore posited a more practical, more dynamic view of a human being pulsating with change, actively selecting the relevant from the world of experience, and combining this experience in adaptive ways. These themes were soon to become the dominant approach in early twentieth century American psychology, which was called “functional.” Themes from James continue to reverberate throughout psychological thinking into the twenty-first century.