How did William James change the study of psychology at Harvard University?

William James transformed the study of psychology at Harvard University by shifting it away from traditional "mental science" and toward physiological psychology. This transition effectively moved psychology out of the realm of theology and into the domain of laboratory science.1

By treating psychology as a biological discipline, James established the functional point of view, which viewed thinking and knowledge as instruments essential for survival. His work helped formalize psychology as a distinct academic discipline and laid the foundation for the school of functionalism. His monumental publication, The Principles of Psychology, became a definitive text that integrated psychophysics and challenged the existing "genteel tradition" of academic philosophy. Through these efforts, James redefined psychology as an empirical, investigative field rather than a mere exercise in mental philosophy.12