A little leaven leaveneth the whole lump. (Galatians 5:9)
PASS IT ON, the official A.A. biography of Alcoholics Anonymous co-founder Bill Wilson, describes William James as “a founding father of American psychology,”  and notes that James “had made a detailed analysis of a wide number of religion or conversion experiences.” 
William James’ book, The Varieties of Religious Experience, had a profound effect on the development and formation of Alcoholics Anonymous. According to Bill Wilson’s official A.A. biography, “[Wilson] would later say that James, though long in his grave, had been a founder of Alcoholics Anonymous.” 
James was also a great influence on other purported Christian influences such as Anne Smith and Sam Shoemaker.
So, was James a Christian? Consider this following exchange betweenTom McMahon and Deidre Bobgan that took place during The Berean Call radio program:
But once [Bill Wilson] finds somebody who has the spiritual experience, then he goes through a spiritual experience, but then he has to try and figure out what’s the basis for this and really where I am going here is, his leaning upon a man who is probably known as the father of modern psychology and that’s William James, the Harvard psychologist and philosopher.
Yes, instead of going to the Bible, he went to William James’ book, The Varieties of Religious Experience . Now, William James was 1842 to 1910, and is considered the father of American psychology and he was intrigued with mystical and existential experiences. People would report these to him and he was very fascinated about it. Now, he didn’t care about the religious persuasion of mystics as long as they achieved a personal experience. He was fascinated by people who experienced these kinds of things and so [James] wrote this: “In mystic states we both become one with the absolute and we become aware of our oneness. This is the everlasting and triumphant mystical tradition hardly offered by differences of clime or creed, in Hinduism, in Neo-Platonism, in Sufism, in Christian mysticism and Whitmanism we find the same recurring notes so there is about mystical utterances and eternal unanimity.” So, Wilson went to William James for the explanation rather than to the Bible. And so here what we see is, you see, Bill Wilson’s experience fit William James’ description than anything in scripture. So he grabbed hold of that and what he continued to look for his entire life and work with AA was anything that would bring a person into the spiritual realm. That’s why he went into the idea of spiritism, séances, necromancy, speaking with the dead and he had various experiences of meeting with various spirit guides.  (emphasis mine)
According to author Dick B. “Both Bill Wilson and Dr. Bob studied William James’ The Varieties of Religious Experience, from which Bill had concluded there was a validation of his own ‘hot flash’ conversion experience. Little recognized too were the New Thought language and ideas that filtered into A.A. language via Rev. Sam Shoemaker’s writings and those of others, including Anne Smith. Shoemaker particularly relied upon James’ writings on self-surrender and conversion.” 
James didn’t care what one believed in. All spiritual experience was valid in his eyes. And so, once again, a key factor in A.A.’s spiritual foundation has nothing to do with Christianity.
1. PASS IT ON, pg.124
4. Why Does The Church Support Alcoholics Anonymous?, The Berean Call radio program http://www.thebereancall.org/content/why-does-church-support-12-step-programs
5. http://silkworth.net/dickb/a_way_out. html