who said psychology is the science of mental life
Psychology In 1890, William James defined psychology as "the science of mental life, both of its phenomena and their conditions". This definition enjoyed widespread currency for decades. However, this meaning was contested, notably by radical behaviorists such as John B. Watson, who in his 1913 manifesto defined the discipline of psychology as the acquisition of information useful to the control of behavior. Also since James defined it, the term more strongly connotes techniques of scientific experimentation.[11][12] Folk psychology refers to the understanding of ordinary people, as contrasted with that of psychology professionals.[13]
The Principles of Psychology The Principles of Psychology is an 1890 book about psychology by William James, an American philosopher and psychologist who trained to be a physician before going into psychology. There are four methods from James' book: stream of consciousness (James' most famous psychological metaphor); emotion (later known as the James–Lange theory); habit (human habits are constantly formed to achieve certain results); and will (through James' personal experiences in life).