William James believed that mystical experiences consist of four distinguishing features
Passivity - The person has no control over them
Ineffable - They cannot be described by the human language
Noetic - They convey knowledge of the universe
Transient - They don't last long and only happen once in a lifetime
In all religious experiences, James identifies a feeling of deep inner peace, joy, great emotional intensity and an unshakable claim that God has been encountered in a "bipolar event" (Beyond human control and understanding)
These feelings can be brought about in ways other than prayer and worship - for example, hallucinogenic drugs