James's method was empirical because all so-called facts and conclusions regarding the data are "hypotheses liable to modification in the course of future experience." His method was radical because he regarded the unity and order of the universe in itself as a hypothesis. James wanted to be loyal to all of the data, and not exclude any data, and to collect it "together without any special a priori theological system." Rational thought is to follow the data of our experience. Based on this method, for instance, he observed that mystical states were interpreted post hoc. Although mysticism itself is radically empirical in that it asks that we take religious experience seriously, James observed that how the mystic makes sense of an experience is not inherent in the experience itself, but is rather constructed after the fact as the person struggles to make sense of a profound experience. Thus, James argued that not only should religious thought follow from the empirical data of our religious experience, but it also should be defined in terms drawn from our experiences.
James's pragmatic spirit is seen in his warm sensitivity to the observation that deep human needs are satisfied through religious experience. More specifically, James's attention centers on the pragmatic moral implications of religious experience and belief in God as known from the practical consequences that follow in people's personal lives after such experiences. Applying pragmatism to religious beliefs, the truth of a theological proposition is to be known by looking at the consequences of the idea. It is not known by its origin or roots but rather by its fruits- "the way in which it works on the whole." James's pragmatism, as a method of problem solving, also allowed him to lay aside dogmatic theologies concerned with the proofs of God and God's metaphysical attributes because they were of no practical significance. In contrast, James noted, God's moral qualities "positively determine fear and hope and expectation, and are foundations for the saintly life." James also believed that philosophy and theology will always have the important task of systematizing and drawing meaning from the ineffable religious experiences of individuals.
Judging James's philosophical psychology of religion by his own pragmatic criteria, one would probably conclude that it worked. It influenced, for instance, many religious-psychological innovators and the therapeutic practices they founded, including Elwood Worcester (founder of the Emmanuel movement), Anton Boisen (founder of clinical pastoral education), and Bill Wilson (founder of Alcoholics Anonymous).
While William James's diverse vocational pursuits during young adulthood may be viewed as a sign of uncertain identity, his explorations may also be fairly viewed as an indication of the complexity of his streams of thought. The waters of James's life reveal deeper and deeper levels of intricate connections, as new interests and areas of study flowed into existing currents. In William James, we find the most original mind in the study of American religion and spirituality. As a physiologist, James anticipated contemporary understandings of the interaction between feeling and emotion and the essential interconnectedness of mind and body. As a psychologist, he anticipated contemporary research findings from studies of consciousness, trauma, dissociation, and temperaments. As a philosopher, James and his colleagues launched what became the most American stream of philosophy, pragmatism. Perhaps what is most remarkable is that he drew upon each of these fields to empower his religious studies.