Mr. Taylor, an associate in psychiatry at Harvard Medical School, is a consultant in the history of psychiatry at the Massachusetts General Hospital.

''The roots of James's thinking can be traced back to the literary psychologies of the early 19th century, the works of Emerson and the transcendentalists, and novelists like Hawthorne and Melville,'' Mr. Taylor said. ''In those days, psychology was transmitted through literary works; in a sense, Hawthorne's ''Scarlet Letter'' is an exegesis of psychosomatic medicine. And, as Henry Murray has pointed out, there is much of what Freud said years later to be found in Melville. It fell to James, in a scientific age, to try to ground these psychological insights in a scientific framework.

Mental Healing Movement

''One form this took was in James's seeking to find what was sound in the mental healing movement of those days. That movement included the teachings of Mary Baker Eddy on Christian Science, and the New Thought Movement, which spawned such denominations as the Unity Church. These were folk psychologies, predecessors to psychotherapy. James believed in the scientific validity of their central assumptions, that mental symptoms could be alleviated by psychotherapeutic means, and that the mind could influence the course of disease.''

James's interest in the mental healers was part of a broader effort by a group of scientists at that time to investigate a range of occult phenomena. Many of the group's members were eminent scientists of the day, including the head of the Smithsonian Institution, the dean of Yale University, the first dean of the Harvard graduate school, and Alexander Graham Bell. Their interest led to the founding in Boston of the American Society for Psychical Research.

It was in this intellectual atmosphere, according to Mr. Taylor, that James embarked on research on mediums, ''thought transference,'' hypnosis and automatic writing. He even invited a famous medium to conduct a series of seances at the James home, to which he invited many scientists and scholars of Boston.

James, however, was by no means naive in his research. He was skeptical of many of the assertions made about the supernatural by those he studied, and he brought to his investigations the rigorous techniques of what was to become experimental psychology, with statistical analyses of the data and attempts to control the conditons under which these phenomenawere studied.

Gertrude Stein's Role

Gertrude Stein, then one of James's students, conducted the major research on automatic writing, in which one pays no attention to what the hand writes. She learned the technique herself, and published two scientific papers on the topic.