erstanding the phenomena of religious life and determining its plausibility.
Why does he not conclude that this transformation, or regeneration of the individual, is simply psychological and natural, rather than the result of an at least partly supernatural incursion? Why does he conclude that there exists this "at least partly" aspect that is not located within the human being, or not derived from the human being?
In thinking about James' conclusions, it helps to look at the medical materialism that he debunks in the early part of the book. His critique of this attitude is an effective, and humorous, one. As he noted, medical materialism is primarily concerned with discounting the experiences, attitudes, and feelings that it deems inferior, rather than explaining all states of mind in terms of organic functions and processes. Medical materialism is similar to the current propensity to call people "neurotic" or "anal" when we disagree with their behavior and attitudes. It is a form of name-calling.
The critique of medical materialism does not assert that physiology has nothing to do with religious experience, or feelings, or any other experience. Indeed, James indicated that certain saints and religious leaders clearly dealt with specific disorders during their lives and that those might have affected the way in which their religious experience was mediated. He also indicated, however, that this does not negate the significance of a particular religious experience, nor does it completely explain it. It might be one factor, in other words, but it is not a sufficient explanation in most cases. Even if it were sufficient, that would not eliminate spiritual meaning.
In other words, even if St. Paul's vision on the road to Damascus was the result of an epileptic seizure, the meaning he ascribed to it caused him to change his life. The meaning he and others ascribed to that vision caused a community to form and be shaped...