What is the main conflict in The Varieties of Religious Experience by William James?

In The Varieties of Religious Experience: A Study in Human Nature (1902), William James offers a sense of validity to the formerly abstract idea of spiritual experience. With an understanding of physiology, psychology, and philosophy, James studied cases of religious inspiration and concluded there were specific aspects of human consciousness that contained energies that could come to a person's assistance in time of great need. The result is what he refers to as the religious experience.